Move zookeeper jobboard constants to class level

To make it easy to document and inquire on the zookeeper
job constants expose them as class level instead of module
level constants (and use them where needed).

Change-Id: Ice53db104c55ba4a7794a358d56922074d44492b

taskflow/jobs/backends/impl_zookeeper.py

@@ -40,21 +40,6 @@ from taskflow.utils import misc
 
 LOG = logging.getLogger(__name__)
 
-UNCLAIMED_JOB_STATES = (
-    states.UNCLAIMED,
-)
-ALL_JOB_STATES = (
-    states.UNCLAIMED,
-    states.COMPLETE,
-    states.CLAIMED,
-)
-
-# Transaction support was added in 3.4.0
-MIN_ZK_VERSION = (3, 4, 0)
-LOCK_POSTFIX = ".lock"
-TRASH_FOLDER = ".trash"
-JOB_PREFIX = 'job'
-
 
 def check_who(meth):
     """Decorator that checks the expected owner type & value restrictions."""
@@ -88,12 +73,12 @@ class ZookeeperJob(base.Job):
             raise ValueError("Only one of 'book_data' or 'book'"
                              " can be provided")
         self._path = k_paths.normpath(path)
-        self._lock_path = self._path + LOCK_POSTFIX
+        self._lock_path = self._path + board.LOCK_POSTFIX
         self._created_on = created_on
         self._node_not_found = False
         basename = k_paths.basename(self._path)
         self._root = self._path[0:-len(basename)]
-        self._sequence = int(basename[len(JOB_PREFIX):])
+        self._sequence = int(basename[len(board.JOB_PREFIX):])
         self._last_state = None
 
     @property
@@ -274,6 +259,16 @@ class ZookeeperJobBoardIterator(six.Iterator):
       over unclaimed jobs.
     """
 
+    _UNCLAIMED_JOB_STATES = (
+        states.UNCLAIMED,
+    )
+
+    _JOB_STATES = (
+        states.UNCLAIMED,
+        states.COMPLETE,
+        states.CLAIMED,
+    )
+
     def __init__(self, board, only_unclaimed=False, ensure_fresh=False):
         self._board = board
         self._jobs = collections.deque()
@@ -290,9 +285,9 @@ class ZookeeperJobBoardIterator(six.Iterator):
 
     def _next_job(self):
         if self.only_unclaimed:
-            allowed_states = UNCLAIMED_JOB_STATES
+            allowed_states = self._UNCLAIMED_JOB_STATES
         else:
-            allowed_states = ALL_JOB_STATES
+            allowed_states = self._JOB_STATES
         job = None
         while self._jobs and job is None:
             maybe_job = self._jobs.popleft()
@@ -343,6 +338,18 @@ class ZookeeperJobBoard(base.NotifyingJobBoard):
     automatically by zookeeper the ephemeral is deemed to be lost).
     """
 
+    #: Transaction support was added in 3.4.0 so we need at least that version.
+    MIN_ZK_VERSION = (3, 4, 0)
+
+    #: Znode **postfix** that lock entries have.
+    LOCK_POSTFIX = ".lock"
+
+    #: Znode child path created under root path that contains trashed jobs.
+    TRASH_FOLDER = ".trash"
+
+    #: Znode **prefix** that job entries have.
+    JOB_PREFIX = 'job'
+
     def __init__(self, name, conf,
                  client=None, persistence=None, emit_notifications=True):
         super(ZookeeperJobBoard, self).__init__(name, conf)
@@ -359,7 +366,7 @@ class ZookeeperJobBoard(base.NotifyingJobBoard):
             raise ValueError("Zookeeper path must be absolute")
         self._path = path
         self._trash_path = self._path.replace(k_paths.basename(self._path),
-                                              TRASH_FOLDER)
+                                              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
@@ -375,7 +382,7 @@ class ZookeeperJobBoard(base.NotifyingJobBoard):
         self._job_watcher = None
         # Since we use sequenced ids this will be the path that the sequences
         # are prefixed with, for example, job0000000001, job0000000002, ...
-        self._job_base = k_paths.join(path, JOB_PREFIX)
+        self._job_base = k_paths.join(path, self.JOB_PREFIX)
         self._worker = None
         self._emit_notifications = bool(emit_notifications)
         self._connected = False
@@ -481,7 +488,8 @@ class ZookeeperJobBoard(base.NotifyingJobBoard):
         LOG.debug("Got children %s under path %s", children, self.path)
         child_paths = []
         for c in children:
-            if c.endswith(LOCK_POSTFIX) or not c.startswith(JOB_PREFIX):
+            if (c.endswith(self.LOCK_POSTFIX) or
+                    not c.startswith(self.JOB_PREFIX)):
                 # Skip lock paths or non-job-paths (these are not valid jobs)
                 continue
             child_paths.append(k_paths.join(self.path, c))
@@ -788,7 +796,7 @@ class ZookeeperJobBoard(base.NotifyingJobBoard):
                                   "Failed to connect to zookeeper")
         try:
             if self._conf.get('check_compatible', True):
-                kazoo_utils.check_compatible(self._client, MIN_ZK_VERSION)
+                kazoo_utils.check_compatible(self._client, self.MIN_ZK_VERSION)
             if self._worker is None and self._emit_notifications:
                 self._worker = futures.ThreadPoolExecutor(max_workers=1)
             self._client.ensure_path(self.path)

taskflow/tests/unit/jobs/test_zk_job.py

@@ -32,11 +32,13 @@ from taskflow.utils import persistence_utils as p_utils
 
 
 TEST_PATH_TPL = '/taskflow/board-test/%s'
-_ZOOKEEPER_AVAILABLE = test_utils.zookeeper_available(
+ZOOKEEPER_AVAILABLE = test_utils.zookeeper_available(
-    impl_zookeeper.MIN_ZK_VERSION)
+    impl_zookeeper.ZookeeperJobBoard.MIN_ZK_VERSION)
+TRASH_FOLDER = impl_zookeeper.ZookeeperJobBoard.TRASH_FOLDER
+LOCK_POSTFIX = impl_zookeeper.ZookeeperJobBoard.LOCK_POSTFIX
 
 
-@testtools.skipIf(not _ZOOKEEPER_AVAILABLE, 'zookeeper is not available')
+@testtools.skipIf(not ZOOKEEPER_AVAILABLE, 'zookeeper is not available')
 class ZookeeperJobboardTest(test.TestCase, base.BoardTestMixin):
     def _create_board(self, persistence=None):
 
@@ -137,10 +139,10 @@ class ZakeJobboardTest(test.TestCase, base.BoardTestMixin):
             for (path, value) in paths:
                 if path in self.bad_paths:
                     continue
-                if path.find(impl_zookeeper.TRASH_FOLDER) > -1:
+                if path.find(TRASH_FOLDER) > -1:
                     trashed.append(path)
                 elif (path.find(self.board._job_base) > -1
-                        and not path.endswith(impl_zookeeper.LOCK_POSTFIX)):
+                        and not path.endswith(LOCK_POSTFIX)):
                     jobs.append(path)
 
             self.assertEqual(len(trashed), 1)