Build-out + test a redis backed jobboard

Part of blueprint taskflow-redis-jobs

Change-Id: I7c94e2201c5d933c8a1ec73fc0cf705962e5eef6

doc/source/jobs.rst

@@ -209,6 +209,20 @@ Additional *configuration* parameters:
     See :py:class:`~taskflow.jobs.backends.impl_zookeeper.ZookeeperJobBoard`
     for implementation details.
 
+Redis
+-----
+
+**Board type**: ``'redis'``
+
+Uses `redis`_ to provide the jobboard capabilities and semantics by using
+a redis hash datastructure and individual job ownership keys (that can
+optionally expire after a given amount of time).
+
+.. note::
+
+    See :py:class:`~taskflow.jobs.backends.impl_redis.RedisJobBoard`
+    for implementation details.
+
 Considerations
 ==============
 
@@ -272,11 +286,17 @@ Zookeeper
 
 .. automodule:: taskflow.jobs.backends.impl_zookeeper
 
+Redis
+-----
+
+.. automodule:: taskflow.jobs.backends.impl_redis
+
 Hierarchy
 =========
 
 .. inheritance-diagram::
     taskflow.jobs.base
+    taskflow.jobs.backends.impl_redis
     taskflow.jobs.backends.impl_zookeeper
     :parts: 1
 
@@ -284,3 +304,4 @@ Hierarchy
 .. _zookeeper: http://zookeeper.apache.org/
 .. _kazoo: http://kazoo.readthedocs.org/
 .. _stevedore: http://stevedore.readthedocs.org/
+.. _redis: http://redis.io/

doc/source/utils.rst

@@ -43,6 +43,11 @@ Persistence
 
 .. automodule:: taskflow.utils.persistence_utils
 
+Redis
+~~~~~
+
+.. automodule:: taskflow.utils.redis_utils
+
 Schema
 ~~~~~~
 

setup.cfg

@@ -34,6 +34,7 @@ packages =
 [entry_points]
 taskflow.jobboards =
     zookeeper = taskflow.jobs.backends.impl_zookeeper:ZookeeperJobBoard
+    redis = taskflow.jobs.backends.impl_redis:RedisJobBoard
 
 taskflow.conductors =
     blocking = taskflow.conductors.backends.impl_blocking:BlockingConductor

taskflow/jobs/backends/impl_redis.py

@@ -0,0 +1,951 @@
+# -*- coding: utf-8 -*-
+
+#    Copyright (C) 2015 Yahoo! Inc. All Rights Reserved.
+#
+#    Licensed under the Apache License, Version 2.0 (the "License"); you may
+#    not use this file except in compliance with the License. You may obtain
+#    a copy of the License at
+#
+#         http://www.apache.org/licenses/LICENSE-2.0
+#
+#    Unless required by applicable law or agreed to in writing, software
+#    distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+#    WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+#    License for the specific language governing permissions and limitations
+#    under the License.
+
+import contextlib
+import datetime
+import string
+import threading
+import time
+
+import fasteners
+import msgpack
+from oslo_serialization import msgpackutils
+from oslo_utils import strutils
+from oslo_utils import timeutils
+from oslo_utils import uuidutils
+from redis import exceptions as redis_exceptions
+import six
+from six.moves import range as compat_range
+
+from taskflow import exceptions as exc
+from taskflow.jobs import base
+from taskflow import logging
+from taskflow import states
+from taskflow.types import timing
+from taskflow.utils import misc
+from taskflow.utils import redis_utils as ru
+
+
+LOG = logging.getLogger(__name__)
+
+
+@contextlib.contextmanager
+def _translate_failures():
+    """Translates common redis exceptions into taskflow exceptions."""
+    try:
+        yield
+    except redis_exceptions.ConnectionError:
+        exc.raise_with_cause(exc.JobFailure, "Failed to connect to redis")
+    except redis_exceptions.TimeoutError:
+        exc.raise_with_cause(exc.JobFailure,
+                             "Failed to communicate with redis, connection"
+                             " timed out")
+    except redis_exceptions.RedisError:
+        exc.raise_with_cause(exc.JobFailure,
+                             "Failed to communicate with redis,"
+                             " internal error")
+
+
+class RedisJob(base.Job):
+    """A redis job."""
+
+    def __init__(self, board, name, sequence, key,
+                 uuid=None, details=None,
+                 created_on=None, backend=None,
+                 book=None, book_data=None):
+        super(RedisJob, self).__init__(board, name,
+                                       uuid=uuid, details=details,
+                                       backend=backend,
+                                       book=book, book_data=book_data)
+        self._created_on = created_on
+        self._client = board._client
+        self._redis_version = board._redis_version
+        self._sequence = sequence
+        self._key = key
+        self._last_modified_key = board.join(key + board.LAST_MODIFIED_POSTFIX)
+        self._owner_key = board.join(key + board.OWNED_POSTFIX)
+
+    @property
+    def key(self):
+        """Key (in board listings/trash hash) the job data is stored under."""
+        return self._key
+
+    @property
+    def last_modified_key(self):
+        """Key the job last modified data is stored under."""
+        return self._last_modified_key
+
+    @property
+    def owner_key(self):
+        """Key the job claim + data of the owner is stored under."""
+        return self._owner_key
+
+    @property
+    def sequence(self):
+        """Sequence number of the current job."""
+        return self._sequence
+
+    def expires_in(self):
+        """How many seconds until the claim expires.
+
+        Returns the number of seconds until the ownership entry expires or
+        :attr:`~taskflow.utils.redis_utils.UnknownExpire.DOES_NOT_EXPIRE` or
+        :attr:`~taskflow.utils.redis_utils.UnknownExpire.KEY_NOT_FOUND` if it
+        does not expire or if the expiry can not be determined (perhaps the
+        :attr:`.owner_key` expired at/before time of inquiry?).
+        """
+        with _translate_failures():
+            return ru.get_expiry(self._client, self._owner_key,
+                                 prior_version=self._redis_version)
+
+    def extend_expiry(self, expiry):
+        """Extends the owner key (aka the claim) expiry for this job.
+
+        NOTE(harlowja): if the claim for this job did **not** previously
+        have an expiry associated with it, calling this method will create
+        one (and after that time elapses the claim on this job will cease
+        to exist).
+
+        Returns ``True`` if the expiry request was performed
+        otherwise ``False``.
+        """
+        with _translate_failures():
+            return ru.apply_expiry(self._client, self._owner_key, expiry,
+                                   prior_version=self._redis_version)
+
+    def __lt__(self, other):
+        if self.created_on == other.created_on:
+            return self.sequence < other.sequence
+        else:
+            return self.created_on < other.created_on
+
+    @property
+    def created_on(self):
+        return self._created_on
+
+    @property
+    def last_modified(self):
+        with _translate_failures():
+            raw_last_modified = self._client.get(self._last_modified_key)
+        last_modified = None
+        if raw_last_modified:
+            last_modified = self._board._loads(
+                raw_last_modified, root_types=(datetime.datetime,))
+            # NOTE(harlowja): just incase this is somehow busted (due to time
+            # sync issues/other), give back the most recent one (since redis
+            # does not maintain clock information; we could have this happen
+            # due to now clients who mutate jobs also send the time in).
+            last_modified = max(last_modified, self._created_on)
+        return last_modified
+
+    @property
+    def state(self):
+        listings_key = self._board.listings_key
+        owner_key = self._owner_key
+        listings_sub_key = self._key
+
+        def _do_fetch(p):
+            # NOTE(harlowja): state of a job in redis is not set into any
+            # explicit 'state' field, but is maintained by what nodes exist in
+            # redis instead (ie if a owner key exists, then we know a owner
+            # is active, if no job data exists and no owner, then we know that
+            # the job is unclaimed, and so-on)...
+            p.multi()
+            p.hexists(listings_key, listings_sub_key)
+            p.exists(owner_key)
+            job_exists, owner_exists = p.execute()
+            if not job_exists:
+                if owner_exists:
+                    # This should **not** be possible due to lua code ordering
+                    # but let's log an INFO statement if it does happen (so
+                    # that it can be investigated)...
+                    LOG.info("Unexpected owner key found at '%s' when job"
+                             " key '%s[%s]' was not found", owner_key,
+                             listings_key, listings_sub_key)
+                return states.COMPLETE
+            else:
+                if owner_exists:
+                    return states.CLAIMED
+                else:
+                    return states.UNCLAIMED
+
+        with _translate_failures():
+            return self._client.transaction(_do_fetch,
+                                            listings_key, owner_key,
+                                            value_from_callable=True)
+
+
+class RedisJobBoard(base.JobBoard):
+    """A jobboard backed by `redis`_.
+
+    Powered by the `redis-py <http://redis-py.readthedocs.org/>`_ library.
+
+    This jobboard creates job entries by listing jobs in a redis `hash`_. This
+    hash contains jobs that can be actively worked on by (and examined/claimed
+    by) some set of eligible consumers. Job posting is typically performed
+    using the :meth:`.post` method (this creates a hash entry with job
+    contents/details encoded in `msgpack`_). The users of these
+    jobboard(s) (potentially on disjoint sets of machines) can then
+    iterate over the available jobs and decide if they want to attempt to
+    claim one of the jobs they have iterated over. If so they will then
+    attempt to contact redis and they will attempt to create a key in
+    redis (using a embedded lua script to perform this atomically) to claim a
+    desired job. If the entity trying to use the jobboard to :meth:`.claim`
+    the job is able to create that lock/owner key then it will be
+    allowed (and expected) to perform whatever *work* the contents of that
+    job described. Once the claiming entity is finished the lock/owner key
+    and the `hash`_ entry will be deleted (if successfully completed) in a
+    single request (also using a embedded lua script to perform this
+    atomically). If the claiming entity is not successful (or the entity
+    that claimed the job dies) the lock/owner key can be released
+    automatically (by **optional** usage of a claim expiry) or by
+    using :meth:`.abandon` to manually abandon the job so that it can be
+    consumed/worked on by others.
+
+    NOTE(harlowja): by default the :meth:`.claim` has no expiry (which
+    means claims will be persistent, even under claiming entity failure). To
+    ensure a expiry occurs pass a numeric value for the ``expiry`` keyword
+    argument to the :meth:`.claim` method that defines how many seconds the
+    claim should be retained for. When an expiry is used ensure that that
+    claim is kept alive while it is being worked on by using
+    the :py:meth:`~.RedisJob.extend_expiry` method periodically.
+
+    .. _msgpack: http://msgpack.org/
+    .. _redis: http://redis.io/
+    .. _hash: http://redis.io/topics/data-types#hashes
+    """
+
+    CLIENT_CONF_TRANSFERS = tuple([
+        # Host config...
+        ('host', str),
+        ('port', int),
+
+        # See: http://redis.io/commands/auth
+        ('password', str),
+
+        # Data encoding/decoding + error handling
+        ('encoding', str),
+        ('encoding_errors', str),
+
+        # Connection settings.
+        ('socket_timeout', float),
+        ('socket_connect_timeout', float),
+
+        # This one negates the usage of host, port, socket connection
+        # settings as it doesn't use the same kind of underlying socket...
+        ('unix_socket_path', str),
+
+        # Do u want ssl???
+        ('ssl', strutils.bool_from_string),
+        ('ssl_keyfile', str),
+        ('ssl_certfile', str),
+        ('ssl_cert_reqs', str),
+        ('ssl_ca_certs', str),
+
+        # See: http://www.rediscookbook.org/multiple_databases.html
+        ('db', int),
+    ])
+    """
+    Keys (and value type converters) that we allow to proxy from the jobboard
+    configuration into the redis client (used to configure the redis client
+    internals if no explicit client is provided via the ``client`` keyword
+    argument).
+
+    See: http://redis-py.readthedocs.org/en/latest/#redis.Redis
+
+    See: https://github.com/andymccurdy/redis-py/blob/2.10.3/redis/client.py
+    """
+
+    #: Postfix (combined with job key) used to make a jobs owner key.
+    OWNED_POSTFIX = b".owned"
+
+    #: Postfix (combined with job key) used to make a jobs last modified key.
+    LAST_MODIFIED_POSTFIX = b".last_modified"
+
+    #: Default namespace for keys when none is provided.
+    DEFAULT_NAMESPACE = b'taskflow'
+
+    MIN_REDIS_VERSION = (2, 6)
+    """
+    Minimum redis version this backend requires.
+
+    This version is required since we need the built-in server-side lua
+    scripting support that is included in 2.6 and newer.
+    """
+
+    NAMESPACE_SEP = b':'
+    """
+    Separator that is used to combine a key with the namespace (to get
+    the **actual** key that will be used).
+    """
+
+    KEY_PIECE_SEP = b'.'
+    """
+    Separator that is used to combine a bunch of key pieces together (to get
+    the **actual** key that will be used).
+    """
+
+    #: Expected lua response status field when call is ok.
+    SCRIPT_STATUS_OK = "ok"
+
+    #: Expected lua response status field when call is **not** ok.
+    SCRIPT_STATUS_ERROR = "error"
+
+    #: Expected lua script error response when the owner is not as expected.
+    SCRIPT_NOT_EXPECTED_OWNER = "Not expected owner!"
+
+    #: Expected lua script error response when the owner is not findable.
+    SCRIPT_UNKNOWN_OWNER = "Unknown owner!"
+
+    #: Expected lua script error response when the job is not findable.
+    SCRIPT_UNKNOWN_JOB = "Unknown job!"
+
+    #: Expected lua script error response when the job is already claimed.
+    SCRIPT_ALREADY_CLAIMED = "Job already claimed!"
+
+    SCRIPT_TEMPLATES = {
+        'consume': """
+-- Extract *all* the variables (so we can easily know what they are)...
+local owner_key = KEYS[1]
+local listings_key = KEYS[2]
+local last_modified_key = KEYS[3]
+
+local expected_owner = ARGV[1]
+local job_key = ARGV[2]
+local result = {}
+if redis.call("hexists", listings_key, job_key) == 1 then
+    if redis.call("exists", owner_key) == 1 then
+        local owner = redis.call("get", owner_key)
+        if owner ~= expected_owner then
+            result["status"] = "${error}"
+            result["reason"] = "${not_expected_owner}"
+            result["owner"] = owner
+        else
+            -- The order is important here, delete the owner first (and if
+            -- that blows up, the job data will still exist so it can be
+            -- worked on again, instead of the reverse)...
+            redis.call("del", owner_key, last_modified_key)
+            redis.call("hdel", listings_key, job_key)
+            result["status"] = "${ok}"
+        end
+    else
+        result["status"] = "${error}"
+        result["reason"] = "${unknown_owner}"
+    end
+else
+    result["status"] = "${error}"
+    result["reason"] = "${unknown_job}"
+end
+return cmsgpack.pack(result)
+""",
+        'claim': """
+local function apply_ttl(key, ms_expiry)
+    if ms_expiry ~= nil then
+        redis.call("pexpire", key, ms_expiry)
+    end
+end
+
+-- Extract *all* the variables (so we can easily know what they are)...
+local owner_key = KEYS[1]
+local listings_key = KEYS[2]
+local last_modified_key = KEYS[3]
+
+local expected_owner = ARGV[1]
+local job_key = ARGV[2]
+local last_modified_blob = ARGV[3]
+
+-- If this is non-numeric (which it may be) this becomes nil
+local ms_expiry = nil
+if ARGV[4] ~= "none" then
+    ms_expiry = tonumber(ARGV[4])
+end
+local result = {}
+if redis.call("hexists", listings_key, job_key) == 1 then
+    if redis.call("exists", owner_key) == 1 then
+        local owner = redis.call("get", owner_key)
+        if owner == expected_owner then
+            -- Owner is the same, leave it alone...
+            redis.call("set", last_modified_key, last_modified_blob)
+            apply_ttl(owner_key, ms_expiry)
+            result["status"] = "${ok}"
+        else
+            result["status"] = "${error}"
+            result["reason"] = "${already_claimed}"
+            result["owner"] = owner
+        end
+    else
+        redis.call("set", owner_key, expected_owner)
+        redis.call("set", last_modified_key, last_modified_blob)
+        apply_ttl(owner_key, ms_expiry)
+        result["status"] = "${ok}"
+    end
+else
+    result["status"] = "${error}"
+    result["reason"] = "${unknown_job}"
+end
+return cmsgpack.pack(result)
+""",
+        'abandon': """
+-- Extract *all* the variables (so we can easily know what they are)...
+local owner_key = KEYS[1]
+local listings_key = KEYS[2]
+local last_modified_key = KEYS[3]
+
+local expected_owner = ARGV[1]
+local job_key = ARGV[2]
+local last_modified_blob = ARGV[3]
+local result = {}
+if redis.call("hexists", listings_key, job_key) == 1 then
+    if redis.call("exists", owner_key) == 1 then
+        local owner = redis.call("get", owner_key)
+        if owner ~= expected_owner then
+            result["status"] = "${error}"
+            result["reason"] = "${not_expected_owner}"
+            result["owner"] = owner
+        else
+            redis.call("del", owner_key)
+            redis.call("set", last_modified_key, last_modified_blob)
+            result["status"] = "${ok}"
+        end
+    else
+        result["status"] = "${error}"
+        result["reason"] = "${unknown_owner}"
+    end
+else
+    result["status"] = "${error}"
+    result["reason"] = "${unknown_job}"
+end
+return cmsgpack.pack(result)
+""",
+        'trash': """
+-- Extract *all* the variables (so we can easily know what they are)...
+local owner_key = KEYS[1]
+local listings_key = KEYS[2]
+local last_modified_key = KEYS[3]
+local trash_listings_key = KEYS[4]
+
+local expected_owner = ARGV[1]
+local job_key = ARGV[2]
+local last_modified_blob = ARGV[3]
+local result = {}
+if redis.call("hexists", listings_key, job_key) == 1 then
+    local raw_posting = redis.call("hget", listings_key, job_key)
+    if redis.call("exists", owner_key) == 1 then
+        local owner = redis.call("get", owner_key)
+        if owner ~= expected_owner then
+            result["status"] = "${error}"
+            result["reason"] = "${not_expected_owner}"
+            result["owner"] = owner
+        else
+            -- This ordering is important (try to first move the value
+            -- and only if that works do we try to do any deletions)...
+            redis.call("hset", trash_listings_key, job_key, raw_posting)
+            redis.call("set", last_modified_key, last_modified_blob)
+            redis.call("del", owner_key)
+            redis.call("hdel", listings_key, job_key)
+            result["status"] = "${ok}"
+        end
+    else
+        result["status"] = "${error}"
+        result["reason"] = "${unknown_owner}"
+    end
+else
+    result["status"] = "${error}"
+    result["reason"] = "${unknown_job}"
+end
+return cmsgpack.pack(result)
+""",
+    }
+    """`Lua`_ **template** scripts that will be used by various methods (they
+    are turned into real scripts and loaded on call into the :func:`.connect`
+    method).
+
+    Some things to note:
+
+    - The lua script is ran serially, so when this runs no other command will
+      be mutating the backend (and redis also ensures that no other script
+      will be running) so atomicity of these scripts are  guaranteed by redis.
+
+    - Transactions were considered (and even mostly implemented) but
+      ultimately rejected since redis does not support rollbacks and
+      transactions can **not** be interdependent (later operations can **not**
+      depend on the results of earlier operations). Both of these issues limit
+      our ability to correctly report errors (with useful messages) and to
+      maintain consistency under failure/contention (due to the inability to
+      rollback). A third and final blow to using transactions was to
+      correctly use them we would have to set a watch on a *very* contentious
+      key (the listings key) which would under load cause clients to retry more
+      often then would be desired (this also increases network load, CPU
+      cycles used, transactions failures triggered and so on).
+
+    - Partial transaction execution is possible due to pre/post ``EXEC``
+      failures (and the lack of rollback makes this worse).
+
+    So overall after thinking, it seemed like having little lua scripts
+    was not that bad (even if it is somewhat convoluted) due to the above and
+    public mentioned issues with transactions. In general using lua scripts
+    for this purpose seems to be somewhat common practice and it solves the
+    issues that came up when transactions were considered & implemented.
+
+    Some links about redis (and redis + lua) that may be useful to look over:
+
+    - `Atomicity of scripts`_
+    - `Scripting and transactions`_
+    - `Why redis does not support rollbacks`_
+    - `Intro to lua for redis programmers`_
+    - `Five key takeaways for developing with redis`_
+    - `Everything you always wanted to know about redis`_ (slides)
+
+    .. _Lua: http://www.lua.org/
+    .. _Atomicity of scripts: http://redis.io/commands/eval#atomicity-of-\
+                              scripts
+    .. _Scripting and transactions: http://redis.io/topics/transactions#redis-\
+                                    scripting-and-transactions
+    .. _Why redis does not support rollbacks: http://redis.io/topics/transa\
+                                              ctions#why-redis-does-not-suppo\
+                                              rt-roll-backs
+    .. _Intro to lua for redis programmers: http://www.redisgreen.net/blog/int\
+                                            ro-to-lua-for-redis-programmers
+    .. _Five key takeaways for developing with redis: https://redislabs.com/bl\
+                                                      og/5-key-takeaways-fo\
+                                                      r-developing-with-redis
+    .. _Everything you always wanted to know about redis: http://www.slidesh
+                                                          are.net/carlosabal\
+                                                          de/everything-you-a\
+                                                          lways-wanted-to-\
+                                                          know-about-redis-b\
+                                                          ut-were-afraid-to-ask
+    """
+
+    @classmethod
+    def _make_client(cls, conf):
+        client_conf = {}
+        for key, value_type_converter in cls.CLIENT_CONF_TRANSFERS:
+            if key in conf:
+                if value_type_converter is not None:
+                    client_conf[key] = value_type_converter(conf[key])
+                else:
+                    client_conf[key] = conf[key]
+        return ru.RedisClient(**client_conf)
+
+    def __init__(self, name, conf,
+                 client=None, persistence=None):
+        super(RedisJobBoard, self).__init__(name, conf)
+        self._closed = True
+        if client is not None:
+            self._client = client
+            self._owns_client = False
+        else:
+            self._client = self._make_client(self._conf)
+            # NOTE(harlowja): This client should not work until connected...
+            self._client.close()
+            self._owns_client = True
+        self._namespace = self._conf.get('namespace', self.DEFAULT_NAMESPACE)
+        self._open_close_lock = threading.RLock()
+        # Redis server version connected to + scripts (populated on connect).
+        self._redis_version = None
+        self._scripts = {}
+        # The backend to load the full logbooks from, since what is sent over
+        # the data connection is only the logbook uuid and name, and not the
+        # full logbook.
+        self._persistence = persistence
+
+    def join(self, key_piece, *more_key_pieces):
+        """Create and return a namespaced key from many segments.
+
+        NOTE(harlowja): all pieces that are text/unicode are converted into
+        their binary equivalent (if they are already binary no conversion
+        takes place) before being joined (as redis expects binary keys and not
+        unicode/text ones).
+        """
+        namespace_pieces = []
+        if self._namespace is not None:
+            namespace_pieces = [self._namespace, self.NAMESPACE_SEP]
+        else:
+            namespace_pieces = []
+        key_pieces = [key_piece]
+        if more_key_pieces:
+            key_pieces.extend(more_key_pieces)
+        for i in compat_range(0, len(namespace_pieces)):
+            namespace_pieces[i] = misc.binary_encode(namespace_pieces[i])
+        for i in compat_range(0, len(key_pieces)):
+            key_pieces[i] = misc.binary_encode(key_pieces[i])
+        namespace = b"".join(namespace_pieces)
+        key = self.KEY_PIECE_SEP.join(key_pieces)
+        return namespace + key
+
+    @property
+    def namespace(self):
+        """The namespace all keys will be prefixed with (or none)."""
+        return self._namespace
+
+    @misc.cachedproperty
+    def trash_key(self):
+        """Key where a hash will be stored with trashed jobs in it."""
+        return self.join(b"trash")
+
+    @misc.cachedproperty
+    def sequence_key(self):
+        """Key where a integer will be stored (used to sequence jobs)."""
+        return self.join(b"sequence")
+
+    @misc.cachedproperty
+    def listings_key(self):
+        """Key where a hash will be stored with active jobs in it."""
+        return self.join(b"listings")
+
+    @property
+    def job_count(self):
+        with _translate_failures():
+            return self._client.hlen(self.listings_key)
+
+    @property
+    def connected(self):
+        return not self._closed
+
+    @fasteners.locked(lock='_open_close_lock')
+    def connect(self):
+        self.close()
+        if self._owns_client:
+            self._client = self._make_client(self._conf)
+        with _translate_failures():
+            # The client maintains a connection pool, so do a ping and
+            # if that works then assume the connection works, which may or
+            # may not be continuously maintained (if the server dies
+            # at a later time, we will become aware of that when the next
+            # op occurs).
+            self._client.ping()
+            is_new_enough, redis_version = ru.is_server_new_enough(
+                self._client, self.MIN_REDIS_VERSION)
+            if not is_new_enough:
+                wanted_version = ".".join([str(p)
+                                           for p in self.MIN_REDIS_VERSION])
+                if redis_version:
+                    raise exc.JobFailure("Redis version %s or greater is"
+                                         " required (version %s is to"
+                                         " old)" % (wanted_version,
+                                                    redis_version))
+                else:
+                    raise exc.JobFailure("Redis version %s or greater is"
+                                         " required" % (wanted_version))
+            else:
+                self._redis_version = redis_version
+                script_params = {
+                    # Status field values.
+                    'ok': self.SCRIPT_STATUS_OK,
+                    'error': self.SCRIPT_STATUS_ERROR,
+
+                    # Known error reasons (when status field is error).
+                    'not_expected_owner': self.SCRIPT_NOT_EXPECTED_OWNER,
+                    'unknown_owner': self.SCRIPT_UNKNOWN_OWNER,
+                    'unknown_job': self.SCRIPT_UNKNOWN_JOB,
+                    'already_claimed': self.SCRIPT_ALREADY_CLAIMED,
+                }
+                prepared_scripts = {}
+                for n, raw_script_tpl in six.iteritems(self.SCRIPT_TEMPLATES):
+                    script_tpl = string.Template(raw_script_tpl)
+                    script_blob = script_tpl.substitute(**script_params)
+                    script = self._client.register_script(script_blob)
+                    prepared_scripts[n] = script
+                self._scripts.update(prepared_scripts)
+                self._closed = False
+
+    @fasteners.locked(lock='_open_close_lock')
+    def close(self):
+        if self._owns_client:
+            self._client.close()
+        self._scripts.clear()
+        self._redis_version = None
+        self._closed = True
+
+    @staticmethod
+    def _dumps(obj):
+        try:
+            return msgpackutils.dumps(obj)
+        except (msgpack.PackException, ValueError):
+            # TODO(harlowja): remove direct msgpack exception access when
+            # oslo.utils provides easy access to the underlying msgpack
+            # pack/unpack exceptions..
+            exc.raise_with_cause(exc.JobFailure,
+                                 "Failed to serialize object to"
+                                 " msgpack blob")
+
+    @staticmethod
+    def _loads(blob, root_types=(dict,)):
+        try:
+            return misc.decode_msgpack(blob, root_types=root_types)
+        except (msgpack.UnpackException, ValueError):
+            # TODO(harlowja): remove direct msgpack exception access when
+            # oslo.utils provides easy access to the underlying msgpack
+            # pack/unpack exceptions..
+            exc.raise_with_cause(exc.JobFailure,
+                                 "Failed to deserialize object from"
+                                 " msgpack blob (of length %s)" % len(blob))
+
+    _decode_owner = staticmethod(misc.binary_decode)
+
+    _encode_owner = staticmethod(misc.binary_encode)
+
+    def find_owner(self, job):
+        owner_key = self.join(job.key + self.OWNED_POSTFIX)
+        with _translate_failures():
+            raw_owner = self._client.get(owner_key)
+            return self._decode_owner(raw_owner)
+
+    def post(self, name, book=None, details=None):
+        job_uuid = uuidutils.generate_uuid()
+        posting = base.format_posting(job_uuid, name,
+                                      created_on=timeutils.utcnow(),
+                                      book=book, details=details)
+        with _translate_failures():
+            sequence = self._client.incr(self.sequence_key)
+            posting.update({
+                'sequence': sequence,
+            })
+        with _translate_failures():
+            raw_posting = self._dumps(posting)
+            raw_job_uuid = six.b(job_uuid)
+            was_posted = bool(self._client.hsetnx(self.listings_key,
+                                                  raw_job_uuid, raw_posting))
+            if not was_posted:
+                raise exc.JobFailure("New job located at '%s[%s]' could not"
+                                     " be posted" % (self.listings_key,
+                                                     raw_job_uuid))
+            else:
+                return RedisJob(self, name, sequence, raw_job_uuid,
+                                uuid=job_uuid, details=details,
+                                created_on=posting['created_on'],
+                                book=book, book_data=posting.get('book'),
+                                backend=self._persistence)
+
+    def wait(self, timeout=None, initial_delay=0.005,
+             max_delay=1.0, sleep_func=time.sleep):
+        if initial_delay > max_delay:
+            raise ValueError("Initial delay %s must be less than or equal"
+                             " to the provided max delay %s"
+                             % (initial_delay, max_delay))
+        # This does a spin-loop that backs off by doubling the delay
+        # up to the provided max-delay. In the future we could try having
+        # a secondary client connected into redis pubsub and use that
+        # instead, but for now this is simpler.
+        w = timing.StopWatch(duration=timeout)
+        w.start()
+        delay = initial_delay
+        while True:
+            jc = self.job_count
+            if jc > 0:
+                it = self.iterjobs()
+                return it
+            else:
+                if w.expired():
+                    raise exc.NotFound("Expired waiting for jobs to"
+                                       " arrive; waited %s seconds"
+                                       % w.elapsed())
+                else:
+                    remaining = w.leftover(return_none=True)
+                    if remaining is not None:
+                        delay = min(delay * 2, remaining, max_delay)
+                    else:
+                        delay = min(delay * 2, max_delay)
+                    sleep_func(delay)
+
+    def iterjobs(self, only_unclaimed=False, ensure_fresh=False):
+        with _translate_failures():
+            raw_postings = self._client.hgetall(self.listings_key)
+        postings = []
+        for raw_job_key, raw_posting in six.iteritems(raw_postings):
+            posting = self._loads(raw_posting)
+            details = posting.get('details', {})
+            job_uuid = posting['uuid']
+            job = RedisJob(self, posting['name'], posting['sequence'],
+                           raw_job_key, uuid=job_uuid, details=details,
+                           created_on=posting['created_on'],
+                           book_data=posting.get('book'),
+                           backend=self._persistence)
+            postings.append(job)
+        postings = sorted(postings)
+        for job in postings:
+            if only_unclaimed:
+                if job.state == states.UNCLAIMED:
+                    yield job
+            else:
+                yield job
+
+    @base.check_who
+    def consume(self, job, who):
+        script = self._get_script('consume')
+        with _translate_failures():
+            raw_who = self._encode_owner(who)
+            raw_result = script(keys=[job.owner_key, self.listings_key,
+                                      job.last_modified_key],
+                                args=[raw_who, job.key])
+            result = self._loads(raw_result)
+        status = result['status']
+        if status != self.SCRIPT_STATUS_OK:
+            reason = result.get('reason')
+            if reason == self.SCRIPT_UNKNOWN_JOB:
+                raise exc.NotFound("Job %s not found to be"
+                                   " consumed" % (job.uuid))
+            elif reason == self.SCRIPT_UNKNOWN_OWNER:
+                raise exc.NotFound("Can not consume job %s"
+                                   " which we can not determine"
+                                   " the owner of" % (job.uuid))
+            elif reason == self.SCRIPT_NOT_EXPECTED_OWNER:
+                raw_owner = result.get('owner')
+                if raw_owner:
+                    owner = self._decode_owner(raw_owner)
+                    raise exc.JobFailure("Can not consume job %s"
+                                         " which is not owned by %s (it is"
+                                         " actively owned by %s)"
+                                         % (job.uuid, who, owner))
+                else:
+                    raise exc.JobFailure("Can not consume job %s"
+                                         " which is not owned by %s"
+                                         % (job.uuid, who))
+            else:
+                raise exc.JobFailure("Failure to consume job %s,"
+                                     " unknown internal error (reason=%s)"
+                                     % (job.uuid, reason))
+
+    @base.check_who
+    def claim(self, job, who, expiry=None):
+        if expiry is None:
+            # On the lua side none doesn't translate to nil so we have
+            # do to this string conversion to make sure that we can tell
+            # the difference.
+            ms_expiry = "none"
+        else:
+            ms_expiry = int(expiry * 1000.0)
+            if ms_expiry <= 0:
+                raise ValueError("Provided expiry (when converted to"
+                                 " milliseconds) must be greater"
+                                 " than zero instead of %s" % (expiry))
+        script = self._get_script('claim')
+        with _translate_failures():
+            raw_who = self._encode_owner(who)
+            raw_result = script(keys=[job.owner_key, self.listings_key,
+                                      job.last_modified_key],
+                                args=[raw_who, job.key,
+                                      # NOTE(harlowja): we need to send this
+                                      # in as a blob (even if it's not
+                                      # set/used), since the format can not
+                                      # currently be created in lua...
+                                      self._dumps(timeutils.utcnow()),
+                                      ms_expiry])
+            result = self._loads(raw_result)
+        status = result['status']
+        if status != self.SCRIPT_STATUS_OK:
+            reason = result.get('reason')
+            if reason == self.SCRIPT_UNKNOWN_JOB:
+                raise exc.NotFound("Job %s not found to be"
+                                   " claimed" % (job.uuid))
+            elif reason == self.SCRIPT_ALREADY_CLAIMED:
+                raw_owner = result.get('owner')
+                if raw_owner:
+                    owner = self._decode_owner(raw_owner)
+                    raise exc.UnclaimableJob("Job %s already"
+                                             " claimed by %s"
+                                             % (job.uuid, owner))
+                else:
+                    raise exc.UnclaimableJob("Job %s already"
+                                             " claimed" % (job.uuid))
+            else:
+                raise exc.JobFailure("Failure to claim job %s,"
+                                     " unknown internal error (reason=%s)"
+                                     % (job.uuid, reason))
+
+    @base.check_who
+    def abandon(self, job, who):
+        script = self._get_script('abandon')
+        with _translate_failures():
+            raw_who = self._encode_owner(who)
+            raw_result = script(keys=[job.owner_key, self.listings_key,
+                                      job.last_modified_key],
+                                args=[raw_who, job.key,
+                                      self._dumps(timeutils.utcnow())])
+            result = self._loads(raw_result)
+        status = result.get('status')
+        if status != self.SCRIPT_STATUS_OK:
+            reason = result.get('reason')
+            if reason == self.SCRIPT_UNKNOWN_JOB:
+                raise exc.NotFound("Job %s not found to be"
+                                   " abandoned" % (job.uuid))
+            elif reason == self.SCRIPT_UNKNOWN_OWNER:
+                raise exc.NotFound("Can not abandon job %s"
+                                   " which we can not determine"
+                                   " the owner of" % (job.uuid))
+            elif reason == self.SCRIPT_NOT_EXPECTED_OWNER:
+                raw_owner = result.get('owner')
+                if raw_owner:
+                    owner = self._decode_owner(raw_owner)
+                    raise exc.JobFailure("Can not abandon job %s"
+                                         " which is not owned by %s (it is"
+                                         " actively owned by %s)"
+                                         % (job.uuid, who, owner))
+                else:
+                    raise exc.JobFailure("Can not abandon job %s"
+                                         " which is not owned by %s"
+                                         % (job.uuid, who))
+            else:
+                raise exc.JobFailure("Failure to abandon job %s,"
+                                     " unknown internal"
+                                     " error (status=%s, reason=%s)"
+                                     % (job.uuid, status, reason))
+
+    def _get_script(self, name):
+        try:
+            return self._scripts[name]
+        except KeyError:
+            exc.raise_with_cause(exc.NotFound,
+                                 "Can not access %s script (has this"
+                                 " board been connected?)" % name)
+
+    @base.check_who
+    def trash(self, job, who):
+        script = self._get_script('trash')
+        with _translate_failures():
+            raw_who = self._encode_owner(who)
+            raw_result = script(keys=[job.owner_key, self.listings_key,
+                                      job.last_modified_key, self.trash_key],
+                                args=[raw_who, job.key,
+                                      self._dumps(timeutils.utcnow())])
+            result = self._loads(raw_result)
+        status = result['status']
+        if status != self.SCRIPT_STATUS_OK:
+            reason = result.get('reason')
+            if reason == self.SCRIPT_UNKNOWN_JOB:
+                raise exc.NotFound("Job %s not found to be"
+                                   " trashed" % (job.uuid))
+            elif reason == self.SCRIPT_UNKNOWN_OWNER:
+                raise exc.NotFound("Can not trash job %s"
+                                   " which we can not determine"
+                                   " the owner of" % (job.uuid))
+            elif reason == self.SCRIPT_NOT_EXPECTED_OWNER:
+                raw_owner = result.get('owner')
+                if raw_owner:
+                    owner = self._decode_owner(raw_owner)
+                    raise exc.JobFailure("Can not trash job %s"
+                                         " which is not owned by %s (it is"
+                                         " actively owned by %s)"
+                                         % (job.uuid, who, owner))
+                else:
+                    raise exc.JobFailure("Can not trash job %s"
+                                         " which is not owned by %s"
+                                         % (job.uuid, who))
+            else:
+                raise exc.JobFailure("Failure to trash job %s,"
+                                     " unknown internal error (reason=%s)"
+                                     % (job.uuid, reason))

taskflow/jobs/backends/impl_zookeeper.py

@@ -41,37 +41,17 @@ from taskflow.utils import misc
 LOG = logging.getLogger(__name__)
 
 
-def check_who(meth):
-    """Decorator that checks the expected owner type & value restrictions."""
-
-    @six.wraps(meth)
-    def wrapper(self, job, who, *args, **kwargs):
-        if not isinstance(who, six.string_types):
-            raise TypeError("Job applicant must be a string type")
-        if len(who) == 0:
-            raise ValueError("Job applicant must be non-empty")
-        return meth(self, job, who, *args, **kwargs)
-
-    return wrapper
-
-
 class ZookeeperJob(base.Job):
     """A zookeeper job."""
 
-    def __init__(self, name, board, client, backend, path,
+    def __init__(self, board, name, client, path,
                  uuid=None, details=None, book=None, book_data=None,
-                 created_on=None):
-        super(ZookeeperJob, self).__init__(name, uuid=uuid, details=details)
-        self._board = board
-        self._book = book
-        if not book_data:
-            book_data = {}
-        self._book_data = book_data
+                 created_on=None, backend=None):
+        super(ZookeeperJob, self).__init__(board, name,
+                                           uuid=uuid, details=details,
+                                           backend=backend,
+                                           book=book, book_data=book_data)
         self._client = client
-        self._backend = backend
-        if all((self._book, self._book_data)):
-            raise ValueError("Only one of 'book_data' or 'book'"
-                             " can be provided")
         self._path = k_paths.normpath(path)
         self._lock_path = self._path + board.LOCK_POSTFIX
         self._created_on = created_on
@@ -82,10 +62,12 @@ class ZookeeperJob(base.Job):
 
     @property
     def lock_path(self):
+        """Path the job lock/claim and owner znode is stored."""
         return self._lock_path
 
     @property
     def path(self):
+        """Path the job data znode is stored."""
         return self._path
 
     @property
@@ -154,28 +136,8 @@ class ZookeeperJob(base.Job):
                 self._node_not_found = True
         return self._created_on
 
-    @property
-    def board(self):
-        return self._board
-
-    def _load_book(self):
-        book_uuid = self.book_uuid
-        if self._backend is not None and book_uuid is not None:
-            # TODO(harlowja): we are currently limited by assuming that the
-            # job posted has the same backend as this loader (to start this
-            # seems to be a ok assumption, and can be adjusted in the future
-            # if we determine there is a use-case for multi-backend loaders,
-            # aka a registry of loaders).
-            with contextlib.closing(self._backend.get_connection()) as conn:
-                return conn.get_logbook(book_uuid)
-        # No backend to fetch from or no uuid specified
-        return None
-
     @property
     def state(self):
-        return self._fetch_state()
-
-    def _fetch_state(self):
         owner = self.board.find_owner(self)
         job_data = {}
         try:
@@ -217,30 +179,6 @@ class ZookeeperJob(base.Job):
     def __hash__(self):
         return hash(self.path)
 
-    @property
-    def book(self):
-        if self._book is None:
-            self._book = self._load_book()
-        return self._book
-
-    @property
-    def book_uuid(self):
-        if self._book:
-            return self._book.uuid
-        if self._book_data:
-            return self._book_data.get('uuid')
-        else:
-            return None
-
-    @property
-    def book_name(self):
-        if self._book:
-            return self._book.name
-        if self._book_data:
-            return self._book_data.get('name')
-        else:
-            return None
-
 
 class ZookeeperJobBoardIterator(six.Iterator):
     """Iterator over a zookeeper jobboard that iterates over potential jobs.
@@ -273,6 +211,7 @@ class ZookeeperJobBoardIterator(six.Iterator):
 
     @property
     def board(self):
+        """The board this iterator was created from."""
         return self._board
 
     def __iter__(self):
@@ -310,28 +249,32 @@ class ZookeeperJobBoardIterator(six.Iterator):
 
 
 class ZookeeperJobBoard(base.NotifyingJobBoard):
-    """A jobboard backend by zookeeper.
+    """A jobboard backed by `zookeeper`_.
 
     Powered by the `kazoo <http://kazoo.readthedocs.org/>`_ library.
 
     This jobboard creates *sequenced* persistent znodes in a directory in
-    zookeeper (that directory defaults to ``/taskflow/jobs``) and uses
-    zookeeper watches to notify other jobboards that the job which was posted
-    using the :meth:`.post` method (this creates a znode with contents/details
-    in json). The users of those jobboard(s) (potentially on disjoint sets of
-    machines) can then iterate over the available jobs and decide if they want
+    zookeeper and uses zookeeper watches to notify other jobboards of
+    jobs which were posted using the :meth:`.post` method (this creates a
+    znode with job contents/details encoded in `json`_). The users of these
+    jobboard(s) (potentially on disjoint sets of machines) can then iterate
+    over the available jobs and decide if they want
     to attempt to claim one of the jobs they have iterated over. If so they
     will then attempt to contact zookeeper and they will attempt to create a
     ephemeral znode using the name of the persistent znode + ".lock" as a
     postfix. If the entity trying to use the jobboard to :meth:`.claim` the
     job is able to create a ephemeral znode with that name then it will be
     allowed (and expected) to perform whatever *work* the contents of that
-    job described. Once finished the ephemeral znode and persistent znode may
-    be deleted (if successfully completed) in a single transaction or if not
-    successful (or the entity that claimed the znode dies) the ephemeral
-    znode will be released (either manually by using :meth:`.abandon` or
-    automatically by zookeeper when the ephemeral node and associated session
-    is deemed to have been lost).
+    job described. Once the claiming entity is finished the ephemeral znode
+    and persistent znode will be deleted (if successfully completed) in a
+    single transaction. If the claiming entity is not successful (or the
+    entity that claimed the znode dies) the ephemeral znode will be
+    released (either manually by using :meth:`.abandon` or automatically by
+    zookeeper when the ephemeral node and associated session is deemed to
+    have been lost).
+
+    .. _zookeeper: http://zookeeper.apache.org/
+    .. _json: http://json.org/
     """
 
     #: Transaction support was added in 3.4.0 so we need at least that version.
@@ -366,11 +309,9 @@ class ZookeeperJobBoard(base.NotifyingJobBoard):
         self._path = path
         self._trash_path = self._path.replace(k_paths.basename(self._path),
                                               self.TRASH_FOLDER)
-        # The backend to load the full logbooks from, since whats sent over
-        # the zookeeper data connection is only the logbook uuid and name, and
-        # not currently the full logbook (later when a zookeeper backend
-        # appears we can likely optimize for that backend usage by directly
-        # reading from the path where the data is stored, if we want).
+        # The backend to load the full logbooks from, since what is sent over
+        # the data connection is only the logbook uuid and name, and not the
+        # full logbook.
         self._persistence = persistence
         # Misc. internal details
         self._known_jobs = {}
@@ -401,10 +342,12 @@ class ZookeeperJobBoard(base.NotifyingJobBoard):
 
     @property
     def path(self):
+        """Path where all job znodes will be stored."""
         return self._path
 
     @property
     def trash_path(self):
+        """Path where all trashed job znodes will be stored."""
         return self._trash_path
 
     @property
@@ -476,8 +419,9 @@ class ZookeeperJobBoard(base.NotifyingJobBoard):
                 # jobs information into the known job set (if it's already
                 # existing then just leave it alone).
                 if path not in self._known_jobs:
-                    job = ZookeeperJob(job_data['name'], self,
-                                       self._client, self._persistence, path,
+                    job = ZookeeperJob(self, job_data['name'],
+                                       self._client, path,
+                                       backend=self._persistence,
                                        uuid=job_data['uuid'],
                                        book_data=job_data.get("book"),
                                        details=job_data.get("details", {}),
@@ -536,46 +480,31 @@ class ZookeeperJobBoard(base.NotifyingJobBoard):
                 self._process_child(path, request)
 
     def post(self, name, book=None, details=None):
-
-        def format_posting(job_uuid):
-            posting = {
-                'uuid': job_uuid,
-                'name': name,
-            }
-            if details:
-                posting['details'] = details
-            else:
-                posting['details'] = {}
-            if book is not None:
-                posting['book'] = {
-                    'name': book.name,
-                    'uuid': book.uuid,
-                }
-            return posting
-
         # NOTE(harlowja): Jobs are not ephemeral, they will persist until they
         # are consumed (this may change later, but seems safer to do this until
         # further notice).
         job_uuid = uuidutils.generate_uuid()
+        job_posting = base.format_posting(job_uuid, name,
+                                          book=book, details=details)
+        raw_job_posting = misc.binary_encode(jsonutils.dumps(job_posting))
         with self._wrap(job_uuid, None,
-                        "Posting failure: %s", ensure_known=False):
-            job_posting = format_posting(job_uuid)
-            job_posting = misc.binary_encode(jsonutils.dumps(job_posting))
+                        fail_msg_tpl="Posting failure: %s",
+                        ensure_known=False):
             job_path = self._client.create(self._job_base,
-                                           value=job_posting,
+                                           value=raw_job_posting,
                                            sequence=True,
                                            ephemeral=False)
-            job = ZookeeperJob(name, self, self._client,
-                               self._persistence, job_path,
-                               book=book, details=details,
-                               uuid=job_uuid)
+            job = ZookeeperJob(self, name, self._client, job_path,
+                               backend=self._persistence,
+                               book=book, details=details, uuid=job_uuid,
+                               book_data=job_posting.get('book'))
             with self._job_cond:
                 self._known_jobs[job_path] = job
                 self._job_cond.notify_all()
             self._emit(base.POSTED, details={'job': job})
             return job
 
-    @check_who
+    @base.check_who
     def claim(self, job, who):
         def _unclaimable_try_find_owner(cause):
             try:
@@ -589,7 +518,8 @@ class ZookeeperJobBoard(base.NotifyingJobBoard):
             excp.raise_with_cause(excp.UnclaimableJob,
                                   message, cause=cause)
 
-        with self._wrap(job.uuid, job.path, "Claiming failure: %s"):
+        with self._wrap(job.uuid, job.path,
+                        fail_msg_tpl="Claiming failure: %s"):
             # NOTE(harlowja): post as json which will allow for future changes
             # more easily than a raw string/text.
             value = jsonutils.dumps({
@@ -653,7 +583,9 @@ class ZookeeperJobBoard(base.NotifyingJobBoard):
             excp.raise_with_cause(excp.JobFailure, fail_msg_tpl % (job_uuid))
 
     def find_owner(self, job):
-        with self._wrap(job.uuid, job.path, "Owner query failure: %s"):
+        with self._wrap(job.uuid, job.path,
+                        fail_msg_tpl="Owner query failure: %s",
+                        ensure_known=False):
             try:
                 self._client.sync(job.lock_path)
                 raw_data, _lock_stat = self._client.get(job.lock_path)
@@ -669,14 +601,15 @@ class ZookeeperJobBoard(base.NotifyingJobBoard):
         return (misc.decode_json(lock_data), lock_stat,
                 misc.decode_json(job_data), job_stat)
 
-    @check_who
+    @base.check_who
     def consume(self, job, who):
-        with self._wrap(job.uuid, job.path, "Consumption failure: %s"):
+        with self._wrap(job.uuid, job.path,
+                        fail_msg_tpl="Consumption failure: %s"):
             try:
                 owner_data = self._get_owner_and_data(job)
                 lock_data, lock_stat, data, data_stat = owner_data
             except k_exceptions.NoNodeError:
-                excp.raise_with_cause(excp.JobFailure,
+                excp.raise_with_cause(excp.NotFound,
                                       "Can not consume a job %s"
                                       " which we can not determine"
                                       " the owner of" % (job.uuid))
@@ -690,14 +623,15 @@ class ZookeeperJobBoard(base.NotifyingJobBoard):
             kazoo_utils.checked_commit(txn)
             self._remove_job(job.path)
 
-    @check_who
+    @base.check_who
     def abandon(self, job, who):
-        with self._wrap(job.uuid, job.path, "Abandonment failure: %s"):
+        with self._wrap(job.uuid, job.path,
+                        fail_msg_tpl="Abandonment failure: %s"):
             try:
                 owner_data = self._get_owner_and_data(job)
                 lock_data, lock_stat, data, data_stat = owner_data
             except k_exceptions.NoNodeError:
-                excp.raise_with_cause(excp.JobFailure,
+                excp.raise_with_cause(excp.NotFound,
                                       "Can not abandon a job %s"
                                       " which we can not determine"
                                       " the owner of" % (job.uuid))
@@ -709,14 +643,15 @@ class ZookeeperJobBoard(base.NotifyingJobBoard):
             txn.delete(job.lock_path, version=lock_stat.version)
             kazoo_utils.checked_commit(txn)
 
-    @check_who
+    @base.check_who
     def trash(self, job, who):
-        with self._wrap(job.uuid, job.path, "Trash failure: %s"):
+        with self._wrap(job.uuid, job.path,
+                        fail_msg_tpl="Trash failure: %s"):
             try:
                 owner_data = self._get_owner_and_data(job)
                 lock_data, lock_stat, data, data_stat = owner_data
             except k_exceptions.NoNodeError:
-                excp.raise_with_cause(excp.JobFailure,
+                excp.raise_with_cause(excp.NotFound,
                                       "Can not trash a job %s"
                                       " which we can not determine"
                                       " the owner of" % (job.uuid))

taskflow/jobs/base.py

@@ -16,6 +16,7 @@
 #    under the License.
 
 import abc
+import contextlib
 
 from oslo_utils import uuidutils
 import six
@@ -43,7 +44,9 @@ class Job(object):
     reverting...
     """
 
-    def __init__(self, name, uuid=None, details=None):
+    def __init__(self, board, name,
+                 uuid=None, details=None, backend=None,
+                 book=None, book_data=None):
         if uuid:
             self._uuid = uuid
         else:
@@ -52,6 +55,12 @@ class Job(object):
         if not details:
             details = {}
         self._details = details
+        self._backend = backend
+        self._board = board
+        self._book = book
+        if not book_data:
+            book_data = {}
+        self._book_data = book_data
 
     @abc.abstractproperty
     def last_modified(self):
@@ -61,34 +70,47 @@ class Job(object):
     def created_on(self):
         """The datetime the job was created on."""
 
-    @abc.abstractproperty
+    @property
     def board(self):
         """The board this job was posted on or was created from."""
+        return self._board
 
     @abc.abstractproperty
     def state(self):
-        """The current state of this job."""
+        """Access the current state of this job."""
+        pass
 
-    @abc.abstractproperty
+    @property
     def book(self):
         """Logbook associated with this job.
 
         If no logbook is associated with this job, this property is None.
         """
+        if self._book is None:
+            self._book = self._load_book()
+        return self._book
 
-    @abc.abstractproperty
+    @property
     def book_uuid(self):
         """UUID of logbook associated with this job.
 
         If no logbook is associated with this job, this property is None.
         """
+        if self._book is not None:
+            return self._book.uuid
+        else:
+            return self._book_data.get('uuid')
 
-    @abc.abstractproperty
+    @property
     def book_name(self):
         """Name of logbook associated with this job.
 
         If no logbook is associated with this job, this property is None.
         """
+        if self._book is not None:
+            return self._book.name
+        else:
+            return self._book_data.get('name')
 
     @property
     def uuid(self):
@@ -105,10 +127,24 @@ class Job(object):
         """The non-uniquely identifying name of this job."""
         return self._name
 
+    def _load_book(self):
+        book_uuid = self.book_uuid
+        if self._backend is not None and book_uuid is not None:
+            # TODO(harlowja): we are currently limited by assuming that the
+            # job posted has the same backend as this loader (to start this
+            # seems to be a ok assumption, and can be adjusted in the future
+            # if we determine there is a use-case for multi-backend loaders,
+            # aka a registry of loaders).
+            with contextlib.closing(self._backend.get_connection()) as conn:
+                return conn.get_logbook(book_uuid)
+        # No backend to fetch from or no uuid specified
+        return None
+
     def __str__(self):
         """Pretty formats the job into something *more* meaningful."""
-        return "%s %s (%s): %s" % (type(self).__name__,
-                                   self.name, self.uuid, self.details)
+        return "%s: %s (uuid=%s, details=%s)" % (type(self).__name__,
+                                                 self.name, self.uuid,
+                                                 self.details)
 
 
 @six.add_metaclass(abc.ABCMeta)
@@ -312,3 +348,40 @@ class NotifyingJobBoard(JobBoard):
     def __init__(self, name, conf):
         super(NotifyingJobBoard, self).__init__(name, conf)
         self.notifier = notifier.Notifier()
+
+
+# Internal helpers for usage by board implementations...
+
+def check_who(meth):
+
+    @six.wraps(meth)
+    def wrapper(self, job, who, *args, **kwargs):
+        if not isinstance(who, six.string_types):
+            raise TypeError("Job applicant must be a string type")
+        if len(who) == 0:
+            raise ValueError("Job applicant must be non-empty")
+        return meth(self, job, who, *args, **kwargs)
+
+    return wrapper
+
+
+def format_posting(uuid, name, created_on=None, last_modified=None,
+                   details=None, book=None):
+    posting = {
+        'uuid': uuid,
+        'name': name,
+    }
+    if created_on is not None:
+        posting['created_on'] = created_on
+    if last_modified is not None:
+        posting['last_modified'] = last_modified
+    if details:
+        posting['details'] = details
+    else:
+        posting['details'] = {}
+    if book is not None:
+        posting['book'] = {
+            'name': book.name,
+            'uuid': book.uuid,
+        }
+    return posting

taskflow/tests/unit/jobs/base.py

@@ -18,20 +18,13 @@ import contextlib
 import threading
 import time
 
-from kazoo.recipe import watchers
-from oslo_utils import uuidutils
-
 from taskflow import exceptions as excp
 from taskflow.persistence.backends import impl_dir
 from taskflow import states
-from taskflow.test import mock
 from taskflow.tests import utils as test_utils
-from taskflow.utils import misc
 from taskflow.utils import persistence_utils as p_utils
 from taskflow.utils import threading_utils
 
-FLUSH_PATH_TPL = '/taskflow/flush-test/%s'
-
 
 @contextlib.contextmanager
 def connect_close(*args):
@@ -44,72 +37,20 @@ def connect_close(*args):
             a.close()
 
 
-@contextlib.contextmanager
-def flush(client, path=None):
-    # This uses the linearity guarantee of zookeeper (and associated libraries)
-    # to create a temporary node, wait until a watcher notifies it's created,
-    # then yield back for more work, and then at the end of that work delete
-    # the created node. This ensures that the operations done in the yield
-    # of this context manager will be applied and all watchers will have fired
-    # before this context manager exits.
-    if not path:
-        path = FLUSH_PATH_TPL % uuidutils.generate_uuid()
-    created = threading.Event()
-    deleted = threading.Event()
-
-    def on_created(data, stat):
-        if stat is not None:
-            created.set()
-            return False  # cause this watcher to cease to exist
-
-    def on_deleted(data, stat):
-        if stat is None:
-            deleted.set()
-            return False  # cause this watcher to cease to exist
-
-    watchers.DataWatch(client, path, func=on_created)
-    client.create(path, makepath=True)
-    if not created.wait(test_utils.WAIT_TIMEOUT):
-        raise RuntimeError("Could not receive creation of %s in"
-                           " the alloted timeout of %s seconds"
-                           % (path, test_utils.WAIT_TIMEOUT))
-    try:
-        yield
-    finally:
-        watchers.DataWatch(client, path, func=on_deleted)
-        client.delete(path, recursive=True)
-        if not deleted.wait(test_utils.WAIT_TIMEOUT):
-            raise RuntimeError("Could not receive deletion of %s in"
-                               " the alloted timeout of %s seconds"
-                               % (path, test_utils.WAIT_TIMEOUT))
-
-
 class BoardTestMixin(object):
+
+    @contextlib.contextmanager
+    def flush(self, client):
+        yield
+
+    def close_client(self, client):
+        pass
+
     def test_connect(self):
         self.assertFalse(self.board.connected)
         with connect_close(self.board):
             self.assertTrue(self.board.connected)
 
-    @mock.patch("taskflow.jobs.backends.impl_zookeeper.misc."
-                "millis_to_datetime")
-    def test_posting_dates(self, mock_dt):
-        epoch = misc.millis_to_datetime(0)
-        mock_dt.return_value = epoch
-
-        with connect_close(self.board):
-            j = self.board.post('test', p_utils.temporary_log_book())
-            self.assertEqual(epoch, j.created_on)
-            self.assertEqual(epoch, j.last_modified)
-
-        self.assertTrue(mock_dt.called)
-
-    def test_board_iter(self):
-        with connect_close(self.board):
-            it = self.board.iterjobs()
-            self.assertEqual(it.board, self.board)
-            self.assertFalse(it.only_unclaimed)
-            self.assertFalse(it.ensure_fresh)
-
     def test_board_iter_empty(self):
         with connect_close(self.board):
             jobs_found = list(self.board.iterjobs())
@@ -155,7 +96,7 @@ class BoardTestMixin(object):
     def test_posting_claim(self):
 
         with connect_close(self.board):
-            with flush(self.client):
+            with self.flush(self.client):
                 self.board.post('test', p_utils.temporary_log_book())
 
             self.assertEqual(1, self.board.job_count)
@@ -164,7 +105,7 @@ class BoardTestMixin(object):
             j = possible_jobs[0]
             self.assertEqual(states.UNCLAIMED, j.state)
 
-            with flush(self.client):
+            with self.flush(self.client):
                 self.board.claim(j, self.board.name)
 
             self.assertEqual(self.board.name, self.board.find_owner(j))
@@ -173,25 +114,24 @@ class BoardTestMixin(object):
             possible_jobs = list(self.board.iterjobs(only_unclaimed=True))
             self.assertEqual(0, len(possible_jobs))
 
-        self.assertRaisesAttrAccess(excp.NotFound, j, 'state')
-        self.assertRaises(excp.NotFound,
-                          self.board.consume, j, self.board.name)
+        self.close_client(self.client)
+        self.assertRaisesAttrAccess(excp.JobFailure, j, 'state')
 
     def test_posting_claim_consume(self):
 
         with connect_close(self.board):
-            with flush(self.client):
+            with self.flush(self.client):
                 self.board.post('test', p_utils.temporary_log_book())
 
             possible_jobs = list(self.board.iterjobs(only_unclaimed=True))
             self.assertEqual(1, len(possible_jobs))
             j = possible_jobs[0]
-            with flush(self.client):
+            with self.flush(self.client):
                 self.board.claim(j, self.board.name)
 
             possible_jobs = list(self.board.iterjobs(only_unclaimed=True))
             self.assertEqual(0, len(possible_jobs))
-            with flush(self.client):
+            with self.flush(self.client):
                 self.board.consume(j, self.board.name)
 
             self.assertEqual(0, len(list(self.board.iterjobs())))
@@ -201,18 +141,18 @@ class BoardTestMixin(object):
     def test_posting_claim_abandon(self):
 
         with connect_close(self.board):
-            with flush(self.client):
+            with self.flush(self.client):
                 self.board.post('test', p_utils.temporary_log_book())
 
             possible_jobs = list(self.board.iterjobs(only_unclaimed=True))
             self.assertEqual(1, len(possible_jobs))
             j = possible_jobs[0]
-            with flush(self.client):
+            with self.flush(self.client):
                 self.board.claim(j, self.board.name)
 
             possible_jobs = list(self.board.iterjobs(only_unclaimed=True))
             self.assertEqual(0, len(possible_jobs))
-            with flush(self.client):
+            with self.flush(self.client):
                 self.board.abandon(j, self.board.name)
 
             possible_jobs = list(self.board.iterjobs(only_unclaimed=True))
@@ -221,12 +161,12 @@ class BoardTestMixin(object):
     def test_posting_claim_diff_owner(self):
 
         with connect_close(self.board):
-            with flush(self.client):
+            with self.flush(self.client):
                 self.board.post('test', p_utils.temporary_log_book())
 
             possible_jobs = list(self.board.iterjobs(only_unclaimed=True))
             self.assertEqual(1, len(possible_jobs))
-            with flush(self.client):
+            with self.flush(self.client):
                 self.board.claim(possible_jobs[0], self.board.name)
 
             possible_jobs = list(self.board.iterjobs())
@@ -236,14 +176,6 @@ class BoardTestMixin(object):
             possible_jobs = list(self.board.iterjobs(only_unclaimed=True))
             self.assertEqual(0, len(possible_jobs))
 
-    def test_posting_no_post(self):
-        with connect_close(self.board):
-            with mock.patch.object(self.client, 'create') as create_func:
-                create_func.side_effect = IOError("Unable to post")
-                self.assertRaises(IOError, self.board.post,
-                                  'test', p_utils.temporary_log_book())
-            self.assertEqual(0, self.board.job_count)
-
     def test_posting_with_book(self):
         backend = impl_dir.DirBackend(conf={
             'path': self.makeTmpDir(),
@@ -252,9 +184,9 @@ class BoardTestMixin(object):
         book, flow_detail = p_utils.temporary_flow_detail(backend)
         self.assertEqual(1, len(book))
 
-        client, board = self._create_board(persistence=backend)
+        client, board = self.create_board(persistence=backend)
         with connect_close(board):
-            with flush(client):
+            with self.flush(client):
                 board.post('test', book)
 
             possible_jobs = list(board.iterjobs(only_unclaimed=True))
@@ -273,11 +205,12 @@ class BoardTestMixin(object):
     def test_posting_abandon_no_owner(self):
 
         with connect_close(self.board):
-            with flush(self.client):
+            with self.flush(self.client):
                 self.board.post('test', p_utils.temporary_log_book())
 
             self.assertEqual(1, self.board.job_count)
             possible_jobs = list(self.board.iterjobs(only_unclaimed=True))
             self.assertEqual(1, len(possible_jobs))
             j = possible_jobs[0]
-            self.assertRaises(excp.JobFailure, self.board.abandon, j, j.name)
+            self.assertRaises(excp.NotFound, self.board.abandon,
+                              j, j.name)

taskflow/tests/unit/jobs/test_entrypoint.py

@@ -19,6 +19,7 @@ import contextlib
 from zake import fake_client
 
 from taskflow.jobs import backends
+from taskflow.jobs.backends import impl_redis
 from taskflow.jobs.backends import impl_zookeeper
 from taskflow import test
 
@@ -47,3 +48,15 @@ class BackendFetchingTest(test.TestCase):
         with contextlib.closing(backends.fetch('test', conf, **kwargs)) as be:
             self.assertIsInstance(be, impl_zookeeper.ZookeeperJobBoard)
             self.assertIs(existing_client, be._client)
+
+    def test_redis_entry_point_text(self):
+        conf = 'redis'
+        with contextlib.closing(backends.fetch('test', conf)) as be:
+            self.assertIsInstance(be, impl_redis.RedisJobBoard)
+
+    def test_redis_entry_point(self):
+        conf = {
+            'board': 'redis',
+        }
+        with contextlib.closing(backends.fetch('test', conf)) as be:
+            self.assertIsInstance(be, impl_redis.RedisJobBoard)

taskflow/tests/unit/jobs/test_redis_job.py

@@ -0,0 +1,81 @@
+# -*- coding: utf-8 -*-
+
+#    Copyright (C) 2013 Yahoo! Inc. All Rights Reserved.
+#
+#    Licensed under the Apache License, Version 2.0 (the "License"); you may
+#    not use this file except in compliance with the License. You may obtain
+#    a copy of the License at
+#
+#         http://www.apache.org/licenses/LICENSE-2.0
+#
+#    Unless required by applicable law or agreed to in writing, software
+#    distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+#    WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+#    License for the specific language governing permissions and limitations
+#    under the License.
+
+import time
+
+from oslo_utils import uuidutils
+import six
+import testtools
+
+from taskflow.jobs.backends import impl_redis
+from taskflow import states
+from taskflow import test
+from taskflow.tests.unit.jobs import base
+from taskflow.tests import utils as test_utils
+from taskflow.utils import persistence_utils as p_utils
+from taskflow.utils import redis_utils as ru
+
+
+REDIS_AVAILABLE = test_utils.redis_available(
+    impl_redis.RedisJobBoard.MIN_REDIS_VERSION)
+
+
+@testtools.skipIf(not REDIS_AVAILABLE, 'redis is not available')
+class RedisJobboardTest(test.TestCase, base.BoardTestMixin):
+    def close_client(self, client):
+        client.close()
+
+    def create_board(self, persistence=None):
+        namespace = uuidutils.generate_uuid()
+        client = ru.RedisClient()
+        config = {
+            'namespace': six.b("taskflow-%s" % namespace),
+        }
+        kwargs = {
+            'client': client,
+            'persistence': persistence,
+        }
+        board = impl_redis.RedisJobBoard('test-board', config, **kwargs)
+        self.addCleanup(board.close)
+        self.addCleanup(self.close_client, client)
+        return (client, board)
+
+    def test_posting_claim_expiry(self):
+
+        with base.connect_close(self.board):
+            with self.flush(self.client):
+                self.board.post('test', p_utils.temporary_log_book())
+
+            self.assertEqual(1, self.board.job_count)
+            possible_jobs = list(self.board.iterjobs(only_unclaimed=True))
+            self.assertEqual(1, len(possible_jobs))
+            j = possible_jobs[0]
+            self.assertEqual(states.UNCLAIMED, j.state)
+
+            with self.flush(self.client):
+                self.board.claim(j, self.board.name, expiry=0.5)
+
+            self.assertEqual(self.board.name, self.board.find_owner(j))
+            self.assertEqual(states.CLAIMED, j.state)
+
+            time.sleep(0.6)
+            self.assertEqual(states.UNCLAIMED, j.state)
+            possible_jobs = list(self.board.iterjobs(only_unclaimed=True))
+            self.assertEqual(1, len(possible_jobs))
+
+    def setUp(self):
+        super(RedisJobboardTest, self).setUp()
+        self.client, self.board = self.create_board()

taskflow/tests/unit/jobs/test_zk_job.py

@@ -14,6 +14,10 @@
 #    License for the specific language governing permissions and limitations
 #    under the License.
 
+import contextlib
+import threading
+
+from kazoo.recipe import watchers
 from oslo_serialization import jsonutils
 from oslo_utils import uuidutils
 import six
@@ -24,13 +28,14 @@ from zake import utils as zake_utils
 from taskflow.jobs.backends import impl_zookeeper
 from taskflow import states
 from taskflow import test
+from taskflow.test import mock
 from taskflow.tests.unit.jobs import base
 from taskflow.tests import utils as test_utils
 from taskflow.utils import kazoo_utils
 from taskflow.utils import misc
 from taskflow.utils import persistence_utils as p_utils
 
-
+FLUSH_PATH_TPL = '/taskflow/flush-test/%s'
 TEST_PATH_TPL = '/taskflow/board-test/%s'
 ZOOKEEPER_AVAILABLE = test_utils.zookeeper_available(
     impl_zookeeper.ZookeeperJobBoard.MIN_ZK_VERSION)
@@ -38,9 +43,81 @@ TRASH_FOLDER = impl_zookeeper.ZookeeperJobBoard.TRASH_FOLDER
 LOCK_POSTFIX = impl_zookeeper.ZookeeperJobBoard.LOCK_POSTFIX
 
 
+class ZookeeperBoardTestMixin(base.BoardTestMixin):
+    def close_client(self, client):
+        kazoo_utils.finalize_client(client)
+
+    @contextlib.contextmanager
+    def flush(self, client, path=None):
+        # This uses the linearity guarantee of zookeeper (and associated
+        # libraries) to create a temporary node, wait until a watcher notifies
+        # it's created, then yield back for more work, and then at the end of
+        # that work delete the created node. This ensures that the operations
+        # done in the yield of this context manager will be applied and all
+        # watchers will have fired before this context manager exits.
+        if not path:
+            path = FLUSH_PATH_TPL % uuidutils.generate_uuid()
+        created = threading.Event()
+        deleted = threading.Event()
+
+        def on_created(data, stat):
+            if stat is not None:
+                created.set()
+                return False  # cause this watcher to cease to exist
+
+        def on_deleted(data, stat):
+            if stat is None:
+                deleted.set()
+                return False  # cause this watcher to cease to exist
+
+        watchers.DataWatch(client, path, func=on_created)
+        client.create(path, makepath=True)
+        if not created.wait(test_utils.WAIT_TIMEOUT):
+            raise RuntimeError("Could not receive creation of %s in"
+                               " the alloted timeout of %s seconds"
+                               % (path, test_utils.WAIT_TIMEOUT))
+        try:
+            yield
+        finally:
+            watchers.DataWatch(client, path, func=on_deleted)
+            client.delete(path, recursive=True)
+            if not deleted.wait(test_utils.WAIT_TIMEOUT):
+                raise RuntimeError("Could not receive deletion of %s in"
+                                   " the alloted timeout of %s seconds"
+                                   % (path, test_utils.WAIT_TIMEOUT))
+
+    def test_posting_no_post(self):
+        with base.connect_close(self.board):
+            with mock.patch.object(self.client, 'create') as create_func:
+                create_func.side_effect = IOError("Unable to post")
+                self.assertRaises(IOError, self.board.post,
+                                  'test', p_utils.temporary_log_book())
+            self.assertEqual(0, self.board.job_count)
+
+    def test_board_iter(self):
+        with base.connect_close(self.board):
+            it = self.board.iterjobs()
+            self.assertEqual(it.board, self.board)
+            self.assertFalse(it.only_unclaimed)
+            self.assertFalse(it.ensure_fresh)
+
+    @mock.patch("taskflow.jobs.backends.impl_zookeeper.misc."
+                "millis_to_datetime")
+    def test_posting_dates(self, mock_dt):
+        epoch = misc.millis_to_datetime(0)
+        mock_dt.return_value = epoch
+
+        with base.connect_close(self.board):
+            j = self.board.post('test', p_utils.temporary_log_book())
+            self.assertEqual(epoch, j.created_on)
+            self.assertEqual(epoch, j.last_modified)
+
+        self.assertTrue(mock_dt.called)
+
+
 @testtools.skipIf(not ZOOKEEPER_AVAILABLE, 'zookeeper is not available')
-class ZookeeperJobboardTest(test.TestCase, base.BoardTestMixin):
-    def _create_board(self, persistence=None):
+class ZookeeperJobboardTest(test.TestCase, ZookeeperBoardTestMixin):
+    def create_board(self, persistence=None):
 
         def cleanup_path(client, path):
             if not client.connected:
@@ -52,39 +129,39 @@ class ZookeeperJobboardTest(test.TestCase, base.BoardTestMixin):
         board = impl_zookeeper.ZookeeperJobBoard('test-board', {'path': path},
                                                  client=client,
                                                  persistence=persistence)
-        self.addCleanup(kazoo_utils.finalize_client, client)
+        self.addCleanup(self.close_client, client)
         self.addCleanup(cleanup_path, client, path)
         self.addCleanup(board.close)
         return (client, board)
 
     def setUp(self):
         super(ZookeeperJobboardTest, self).setUp()
-        self.client, self.board = self._create_board()
+        self.client, self.board = self.create_board()
 
 
-class ZakeJobboardTest(test.TestCase, base.BoardTestMixin):
-    def _create_board(self, persistence=None):
+class ZakeJobboardTest(test.TestCase, ZookeeperBoardTestMixin):
+    def create_board(self, persistence=None):
         client = fake_client.FakeClient()
         board = impl_zookeeper.ZookeeperJobBoard('test-board', {},
                                                  client=client,
                                                  persistence=persistence)
         self.addCleanup(board.close)
-        self.addCleanup(kazoo_utils.finalize_client, client)
+        self.addCleanup(self.close_client, client)
         return (client, board)
 
     def setUp(self):
         super(ZakeJobboardTest, self).setUp()
-        self.client, self.board = self._create_board()
+        self.client, self.board = self.create_board()
         self.bad_paths = [self.board.path, self.board.trash_path]
         self.bad_paths.extend(zake_utils.partition_path(self.board.path))
 
     def test_posting_owner_lost(self):
 
         with base.connect_close(self.board):
-            with base.flush(self.client):
+            with self.flush(self.client):
                 j = self.board.post('test', p_utils.temporary_log_book())
             self.assertEqual(states.UNCLAIMED, j.state)
-            with base.flush(self.client):
+            with self.flush(self.client):
                 self.board.claim(j, self.board.name)
             self.assertEqual(states.CLAIMED, j.state)
 
@@ -102,10 +179,10 @@ class ZakeJobboardTest(test.TestCase, base.BoardTestMixin):
     def test_posting_state_lock_lost(self):
 
         with base.connect_close(self.board):
-            with base.flush(self.client):
+            with self.flush(self.client):
                 j = self.board.post('test', p_utils.temporary_log_book())
             self.assertEqual(states.UNCLAIMED, j.state)
-            with base.flush(self.client):
+            with self.flush(self.client):
                 self.board.claim(j, self.board.name)
             self.assertEqual(states.CLAIMED, j.state)
 
@@ -123,14 +200,14 @@ class ZakeJobboardTest(test.TestCase, base.BoardTestMixin):
     def test_trashing_claimed_job(self):
 
         with base.connect_close(self.board):
-            with base.flush(self.client):
+            with self.flush(self.client):
                 j = self.board.post('test', p_utils.temporary_log_book())
             self.assertEqual(states.UNCLAIMED, j.state)
-            with base.flush(self.client):
+            with self.flush(self.client):
                 self.board.claim(j, self.board.name)
             self.assertEqual(states.CLAIMED, j.state)
 
-            with base.flush(self.client):
+            with self.flush(self.client):
                 self.board.trash(j, self.board.name)
 
             trashed = []

taskflow/tests/utils.py

@@ -18,6 +18,7 @@ import contextlib
 import string
 import threading
 
+import redis
 import six
 
 from taskflow import exceptions
@@ -27,6 +28,7 @@ from taskflow import retry
 from taskflow import task
 from taskflow.types import failure
 from taskflow.utils import kazoo_utils
+from taskflow.utils import redis_utils
 
 ARGS_KEY = '__args__'
 KWARGS_KEY = '__kwargs__'
@@ -73,6 +75,18 @@ def zookeeper_available(min_version, timeout=3):
         kazoo_utils.finalize_client(client)
 
 
+def redis_available(min_version):
+    client = redis.StrictRedis()
+    try:
+        client.ping()
+    except Exception:
+        return False
+    else:
+        ok, redis_version = redis_utils.is_server_new_enough(client,
+                                                             min_version)
+        return ok
+
+
 class NoopRetry(retry.AlwaysRevert):
     pass
 

taskflow/utils/misc.py

@@ -28,6 +28,7 @@ import types
 
 import enum
 from oslo_serialization import jsonutils
+from oslo_serialization import msgpackutils
 from oslo_utils import encodeutils
 from oslo_utils import importutils
 from oslo_utils import netutils
@@ -285,19 +286,7 @@ def binary_decode(data, encoding='utf-8', errors='strict'):
                                        errors=errors)
 
 
-def decode_json(raw_data, root_types=(dict,)):
-    """Parse raw data to get JSON object.
-
-    Decodes a JSON from a given raw data binary and checks that the root
-    type of that decoded object is in the allowed set of types (by
-    default a JSON object/dict should be the root type).
-    """
-    try:
-        data = jsonutils.loads(binary_decode(raw_data))
-    except UnicodeDecodeError as e:
-        raise ValueError("Expected UTF-8 decodable data: %s" % e)
-    except ValueError as e:
-        raise ValueError("Expected JSON decodable data: %s" % e)
+def _check_decoded_type(data, root_types=(dict,)):
     if root_types:
         if not isinstance(root_types, tuple):
             root_types = tuple(root_types)
@@ -312,6 +301,40 @@ def decode_json(raw_data, root_types=(dict,)):
     return data
 
 
+def decode_msgpack(raw_data, root_types=(dict,)):
+    """Parse raw data to get decoded object.
+
+    Decodes a msgback encoded 'blob' from a given raw data binary string and
+    checks that the root type of that decoded object is in the allowed set of
+    types (by default a dict should be the root type).
+    """
+    try:
+        data = msgpackutils.loads(raw_data)
+    except Exception as e:
+        # TODO(harlowja): fix this when msgpackutils exposes the msgpack
+        # exceptions so that we can avoid catching just exception...
+        raise ValueError("Expected msgpack decodable data: %s" % e)
+    else:
+        return _check_decoded_type(data, root_types=root_types)
+
+
+def decode_json(raw_data, root_types=(dict,)):
+    """Parse raw data to get decoded object.
+
+    Decodes a JSON encoded 'blob' from a given raw data binary string and
+    checks that the root type of that decoded object is in the allowed set of
+    types (by default a dict should be the root type).
+    """
+    try:
+        data = jsonutils.loads(binary_decode(raw_data))
+    except UnicodeDecodeError as e:
+        raise ValueError("Expected UTF-8 decodable data: %s" % e)
+    except ValueError as e:
+        raise ValueError("Expected JSON decodable data: %s" % e)
+    else:
+        return _check_decoded_type(data, root_types=root_types)
+
+
 class cachedproperty(object):
     """A *thread-safe* descriptor property that is only evaluated once.
 

taskflow/utils/redis_utils.py

@@ -0,0 +1,133 @@
+# -*- coding: utf-8 -*-
+
+#    Copyright (C) 2015 Yahoo! Inc. All Rights Reserved.
+#
+#    Licensed under the Apache License, Version 2.0 (the "License"); you may
+#    not use this file except in compliance with the License. You may obtain
+#    a copy of the License at
+#
+#         http://www.apache.org/licenses/LICENSE-2.0
+#
+#    Unless required by applicable law or agreed to in writing, software
+#    distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+#    WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+#    License for the specific language governing permissions and limitations
+#    under the License.
+
+import enum
+
+import redis
+from redis import exceptions as redis_exceptions
+import six
+
+
+def _raise_on_closed(meth):
+
+    @six.wraps(meth)
+    def wrapper(self, *args, **kwargs):
+        if self.closed:
+            raise redis_exceptions.ConnectionError("Connection has been"
+                                                   " closed")
+        return meth(self, *args, **kwargs)
+
+    return wrapper
+
+
+class RedisClient(redis.StrictRedis):
+    """A redis client that can be closed (and raises on-usage after closed).
+
+    TODO(harlowja): if https://github.com/andymccurdy/redis-py/issues/613 ever
+    gets resolved or merged or other then we can likely remove this.
+    """
+
+    def __init__(self, *args, **kwargs):
+        super(RedisClient, self).__init__(*args, **kwargs)
+        self.closed = False
+
+    def close(self):
+        self.closed = True
+        self.connection_pool.disconnect()
+
+    execute_command = _raise_on_closed(redis.StrictRedis.execute_command)
+    transaction = _raise_on_closed(redis.StrictRedis.transaction)
+    pubsub = _raise_on_closed(redis.StrictRedis.pubsub)
+
+
+class UnknownExpire(enum.IntEnum):
+    """Non-expiry (not ttls) results return from :func:`.get_expiry`.
+
+    See: http://redis.io/commands/ttl or http://redis.io/commands/pttl
+    """
+
+    DOES_NOT_EXPIRE = -1
+    """
+    The command returns ``-1`` if the key exists but has no associated expire.
+    """
+
+    #: The command returns ``-2`` if the key does not exist.
+    KEY_NOT_FOUND = -2
+
+
+DOES_NOT_EXPIRE = UnknownExpire.DOES_NOT_EXPIRE
+KEY_NOT_FOUND = UnknownExpire.KEY_NOT_FOUND
+
+_UNKNOWN_EXPIRE_MAPPING = dict((e.value, e) for e in list(UnknownExpire))
+
+
+def get_expiry(client, key, prior_version=None):
+    """Gets an expiry for a key (using **best** determined ttl method)."""
+    is_new_enough, _prior_version = is_server_new_enough(
+        client, (2, 6), prior_version=prior_version)
+    if is_new_enough:
+        result = client.pttl(key)
+        try:
+            return _UNKNOWN_EXPIRE_MAPPING[result]
+        except KeyError:
+            return result / 1000.0
+    else:
+        result = client.ttl(key)
+        try:
+            return _UNKNOWN_EXPIRE_MAPPING[result]
+        except KeyError:
+            return float(result)
+
+
+def apply_expiry(client, key, expiry, prior_version=None):
+    """Applies an expiry to a key (using **best** determined expiry method)."""
+    is_new_enough, _prior_version = is_server_new_enough(
+        client, (2, 6), prior_version=prior_version)
+    if is_new_enough:
+        # Use milliseconds (as that is what pexpire uses/expects...)
+        ms_expiry = expiry * 1000.0
+        ms_expiry = max(0, int(ms_expiry))
+        result = client.pexpire(key, ms_expiry)
+    else:
+        # Only supports seconds (not subseconds...)
+        sec_expiry = int(expiry)
+        sec_expiry = max(0, sec_expiry)
+        result = client.expire(key, sec_expiry)
+    return bool(result)
+
+
+def is_server_new_enough(client, min_version,
+                         default=False, prior_version=None):
+    """Checks if a client is attached to a new enough redis server."""
+    if not prior_version:
+        try:
+            server_info = client.info()
+        except redis_exceptions.ResponseError:
+            server_info = {}
+        version_text = server_info.get('redis_version', '')
+    else:
+        version_text = prior_version
+    version_pieces = []
+    for p in version_text.split("."):
+        try:
+            version_pieces.append(int(p))
+        except ValueError:
+            break
+    if not version_pieces:
+        return (default, version_text)
+    else:
+        version_pieces = tuple(version_pieces)
+        return (version_pieces >= min_version, version_text)

test-requirements.txt

@@ -15,6 +15,9 @@ kombu>=3.0.7
 zake>=0.1.6 # Apache-2.0
 kazoo>=2.2
 
+# Used for testing redis jobboards
+redis>=2.10.0
+
 # Used for testing database persistence backends.
 SQLAlchemy<1.1.0,>=0.9.7
 alembic>=0.7.2