On OS X (and probably other Operating Systems) it isn't possible to
introspect the value of a semaphore. Account for this by skipping a
test about this.
Change-Id: I97824f9fc4e36de4f7a62c8ce53865e6977dfdfe
For this commit, ssync is just a direct replacement for how
we use rsync. Assuming we switch over to ssync completely
someday and drop rsync, we will then be able to improve the
algorithms even further (removing local objects as we
successfully transfer each one rather than waiting for whole
partitions, using an index.db with hash-trees, etc., etc.)
For easier review, this commit can be thought of in distinct
parts:
1) New global_conf_callback functionality for allowing
services to perform setup code before workers, etc. are
launched. (This is then used by ssync in the object
server to create a cross-worker semaphore to restrict
concurrent incoming replication.)
2) A bit of shifting of items up from object server and
replicator to diskfile or DEFAULT conf sections for
better sharing of the same settings. conn_timeout,
node_timeout, client_timeout, network_chunk_size,
disk_chunk_size.
3) Modifications to the object server and replicator to
optionally use ssync in place of rsync. This is done in
a generic enough way that switching to FutureSync should
be easy someday.
4) The biggest part, and (at least for now) completely
optional part, are the new ssync_sender and
ssync_receiver files. Nice and isolated for easier
testing and visibility into test coverage, etc.
All the usual logging, statsd, recon, etc. instrumentation
is still there when using ssync, just as it is when using
rsync.
Beyond the essential error and exceptional condition
logging, I have not added any additional instrumentation at
this time. Unless there is something someone finds super
pressing to have added to the logging, I think such
additions would be better as separate change reviews.
FOR NOW, IT IS NOT RECOMMENDED TO USE SSYNC ON PRODUCTION
CLUSTERS. Some of us will be in a limited fashion to look
for any subtle issues, tuning, etc. but generally ssync is
an experimental feature. In its current implementation it is
probably going to be a bit slower than rsync, but if all
goes according to plan it will end up much faster.
There are no comparisions yet between ssync and rsync other
than some raw virtual machine testing I've done to show it
should compete well enough once we can put it in use in the
real world.
If you Tweet, Google+, or whatever, be sure to indicate it's
experimental. It'd be best to keep it out of deployment
guides, howtos, etc. until we all figure out if we like it,
find it to be stable, etc.
Change-Id: If003dcc6f4109e2d2a42f4873a0779110fff16d6
Refactor on-disk knowledge out of the object server by pushing the
async update pickle creation to the new DiskFileManager class (name is
not the best, so suggestions welcome), along with the REPLICATOR
method logic. We also move the mount checking and thread pool storage
to the new ondisk.Devices object, which then also becomes the new home
of the audit_location_generator method.
For the object server, a new setup() method is now called at the end
of the controller's construction, and the _diskfile() method has been
renamed to get_diskfile(), to allow implementation specific behavior.
We then hide the need for the REST API layer to know how and where
quarantining needs to be performed. There are now two places it is
checked internally, on open() where we verify the content-length,
name, and x-timestamp metadata, and in the reader on close where the
etag metadata is checked if the entire file was read.
We add a reader class to allow implementations to isolate the WSGI
handling code for that specific environment (it is used no-where else
in the REST APIs). This simplifies the caller's code to just use a
"with" statement once open to avoid multiple points where close needs
to be called.
For a full historical comparison, including the usage patterns see:
https://gist.github.com/portante/5488238
(as of master, 2b639f5, Merge
"Fix 500 from account-quota This Commit
middleware")
--------------------------------+------------------------------------
DiskFileManager(conf)
Methods:
.pickle_async_update()
.get_diskfile()
.get_hashes()
Attributes:
.devices
.logger
.disk_chunk_size
.keep_cache_size
.bytes_per_sync
DiskFile(a,c,o,keep_data_fp=) DiskFile(a,c,o)
Methods: Methods:
*.__iter__()
.close(verify_file=)
.is_deleted()
.is_expired()
.quarantine()
.get_data_file_size()
.open()
.read_metadata()
.create() .create()
.write_metadata()
.delete() .delete()
Attributes: Attributes:
.quarantined_dir
.keep_cache
.metadata
*DiskFileReader()
Methods:
.__iter__()
.close()
Attributes:
+.was_quarantined
DiskWriter() DiskFileWriter()
Methods: Methods:
.write() .write()
.put() .put()
* Note that the DiskFile class * Note that the DiskReader() object
implements all the methods returned by the
necessary for a WSGI app DiskFileOpened.reader() method
iterator implements all the methods
necessary for a WSGI app iterator
+ Note that if the auditor is
refactored to not use the DiskFile
class, see
https://review.openstack.org/44787
then we don't need the
was_quarantined attribute
A reference "in-memory" object server implementation of a backend
DiskFile class in swift/obj/mem_server.py and
swift/obj/mem_diskfile.py.
One can also reference
https://github.com/portante/gluster-swift/commits/diskfile for the
proposed integration with the gluster-swift code based on these
changes.
Change-Id: I44e153fdb405a5743e9c05349008f94136764916
Signed-off-by: Peter Portante <peter.portante@redhat.com>
This reverts commit 7760f41c3ce436cb23b4b8425db3749a3da33d32
Change-Id: I95e57a2563784a8cd5e995cc826afeac0eadbe62
Signed-off-by: Peter Portante <peter.portante@redhat.com>
Place all the methods related to on-disk layout and / or configuration
into a new common module that can be shared by the various modules
using the same on-disk layout.
Change-Id: I27ffd4665d5115ffdde649c48a4d18e12017e6a9
Signed-off-by: Peter Portante <peter.portante@redhat.com>
All access to the data_file fp for DiskFile is moved after the new "open"
method. This prepares to move some additional smarts into DiskFile and reduce
the surface area of the abstraction and the exposure of the underlying
implementation in the object-server.
Future work:
* Consolidate put_metadata to DiskWriter
* Add public "update_metdata" method to DiskFile
* Create DiskReader class to gather all access of methods under "open"
Change-Id: I4de2f265bf099a810c5f1c14b5278d89bd0b382d
We also fix up any other pep8 failures that snuck in from merges along
the way.
Change-Id: I4ea984780ac2eac458c98fe181684eef4e04beaf
Signed-off-by: Peter Portante <peter.portante@redhat.com>
Address all the "hacking" lines that are flagged, and all the modules
that just have one item flagged.
Change-Id: I372a4bdf9c7748f73e38c4fd55e5954f1afade5b
Signed-off-by: Peter Portante <peter.portante@redhat.com>
It seems as this conversion was missed, as a git blame says the first
few lines of DELETE date all the way back to commit 001407b9 "(creiht)
2010-07-12 Initial commit of Swift code".
While we were in here, we moved _parse_path() to a module method as
there appears to be need to keep it as an object controller method.
We also fixed up as many of the tests that directly invoked the object
controller methods to use get_response(), addressing a few
inconsistencies along the way.
Change-Id: If491c7129d61d6fc7d81401fbc3650c29ed80465
Signed-off-by: Peter Portante <peter.portante@redhat.com>
The DELETE object REST API was creating tombstone files with old
timestamps, potentially filling up the disk, as well as sending
container updates.
Here we now make DELETEs with a request timestamp return a 409 (HTTP
Conflict) if a data file exists with a newer timestamp, only creating
tombstones if they have a newer timestamp.
The key fix is to actually read the timestamp metadata from an
existing tombstone file (thanks to Pete Zaitcev for catching this),
and then only create tombstone files with newer timestamps.
We also prevent PUT and POST operations using old timestamps as well.
Change-Id: I631957029d17c6578bca5779367df5144ba01fc9
Signed-off-by: Peter Portante <peter.portante@redhat.com>
This lets us get rid of some really repetitive exception conversion
code, like everybody that called common.utils.get_param() had to catch
a UnicodeDecodeError and turn that into returning HTTPBadRequest. Now
get_param() just raises HTTPBadRequest directly, and the __call__
methods in the account/container/object servers catch and return
it. All that "except UnicodeDecodeError" stuff goes away.
Refactored the path splitting and device validation in the object
server too.
There are other things that can benefit from this as well, but this
patch is big enough.
Change-Id: I2be96ef757d04bfd6af180cd9c92393c841db21f
* new module swift.obj.diskfile
I parameterized two constants from obj.server into the DiskFile's __init__
* DATADIR -> obj_dir
* DISALLOWED_HEADERS -> disallowed_metadata_keys
I'm not sure if this is the right long term abstraction but for now it avoids
circular imports.
Change-Id: I3962202c07c4b2fbfc26f9776c8a5c96292ae199
The unit tests were playing fast and loose with the tombstone marker,
where the test framework was setting up a DiskFile object which had
its data written to the .ts file, not the .data file. This behavior
did not reflect how the interfaces to DiskFile were supposed to
work.
Change-Id: Idd6e8882e062ba2e13489f14189223ab4158677c
Signed-off-by: Peter Portante <peter.portante@redhat.com>
Remove logic of allowed methods list from object, container and account
servers. Instead of it add replicator decorator to utils and use new
decorator for REPLICATE methods in object/account/container servers.
This decorator mark method as special for usfor use only by the
replication.
If the option replication_server is not used, then this mechanism is not
enabled. If the replicaton_server option is set (not None) then the
respective server is a replicator (option value is True) and should use
ONLY the methods marked for replication server using the decorator, or
it is a normal server type and should NOT use methods marked for the
replication server.
Change-Id: I1041b31413cd0c39000317cc57a8c27816e1dfe8
See Bug 1187200 for a full description of the problem.
Part 1:
X-Delete-At-Container added to X-Delete-At-* info
This fixes the bug by passing the expiring-objects-account's
container name onward to the backend object servers. This is in case
the object servers' expiring_objects_container_divisor happens to be
different than the proxy server's, we want to make sure the host,
partition, and device match up with the container name. Different
container names would be fine, but not with mismatched host,
partition, and device info.
Part 2:
The db_replicator now double checks the disk path's partition against
the partition the ring gives back. If they don't match, it logs the
problem but continues to replicate the database to where it should be
and, on success to all proper nodes, removes the local out of place
database.
Bug 1187200
Change-Id: Id0873a3f2198ce285fe0b0c777738eff38bc2438
Add special chars could help checking quote/unquote, encode/decode
problems. Those two is one of most common mistakes.
Change-Id: Ife1c0b481f08c1666d62b4fb51b7fdcdfdbf2ba6
Without a (per-disk) threadpool, requests to a slow disk would affect
all clients by blocking the entire eventlet reactor on
read/write/etc. The slower the disk, the worse the performance. On an
object server, you frequently have at least one slow disk due to
auditing and replication activity sucking up all the available IO. By
kicking those blocking calls out to a separate OS thread, we let the
eventlet reactor make progress in other greenthreads, and by having a
per-disk pool, we ensure that one slow disk can't suck up all the
resources of an entire object server.
There were a few blocking calls that were done with eventlet.tpool,
but that's a fixed-size global threadpool, so I moved them to the
per-disk threadpools. If the object server is configured not to use
per-disk threadpools, (i.e. threads_per_disk = 0, which is the
default), those call sites will still ultimately end up using
eventlet.tpool.execute. You won't end up blocking a whole object
server while waiting for a huge fsync.
If you decide not to use threadpools, the only extra overhead should
be a few extra Python function calls here and there. This is
accomplished by setting threads_per_disk = 0 in the config.
blueprint concurrent-disk-io
Change-Id: I490f8753d926fdcee3a0c65c5aaf715bc2b7c290
RFC 2616 Sec 4.4 Message Length describes how the content-length and
transfer-encoding headers interact. Basically, if chunked transfer
encoding is used, the content-length header value is ignored and if
the content-length header is present, and the request is not using
chunked transfer-encoding, then the content-length must match the body
length.
The only Transfer-Coding value we support in the Transfer-Encoding
header (to date) is "chunked". RFC 2616 Sec 14.41 specifies that if
"multiple encodings have been applied to an entity, the
transfer-codings MUST be listed in the order in which they were
applied." Since we only supported "chunked". If the Transfer-Encoding
header value has multiple transfer-codings, we return a 501 (Not
Implemented) (see RFC 2616 Sec 3.6) without checking if chunked is the
last one specified. Finally, if transfer-encoding is anything but
"chunked", we return a 400 (Bad Request) to the client.
This patch adds a new method, message_length, to the swob request
object which will apply an algorithm based on RFC 2616 Sec 4.4
leveraging the existing content_length property.
In addition to these changes, the proxy server will now notice when
the message length specified by the content-length header is greater
than the configured object maximum size and fail the request with a
413, "Request Entity Too Large", before reading the entire body.
This work flows from https://review.openstack.org/27152.
Change-Id: I5d2a30b89092680dee9d946e1aafd017eaaef8c0
Signed-off-by: Peter Portante <peter.portante@redhat.com>
Towards moving the DiskFile class into place as the API definition for
pluggable DiskFile backends, we hide the file descriptor and the
method of writing data to disks. The mkstemp() method has been renamed
to writer(), and no longer returns an fd, but a new object that
encapsulates the state tracked for writes. This new object is then
used directly to perform the reminder of the write operations and
application of required semantics.
Change-Id: Ib37ed37b34a2ce6b442d69f83ca011c918114434
Signed-off-by: Peter Portante <peter.portante@redhat.com>
Support separate replication ip address:
- Added new function in utils. This function provides ability
to select separate IP address for replication service.
- Db_replicator and object replicators were changed.
Replication process uses new function now.
Replication network parameters:
- Replication network fields (replication_ip, replication_port)
support was added to device dictionary in swift-ring-builder script.
- Changes were made to support new fields in search, show and set_info
functions.
Implementation of replication servers:
- Separate replication servers use the same code as normal replication
servers, but with replication_server parameter = True. When using a
separate replication network, the non-replication servers set
replication_server = False. When there is no separate replication
network (the default case), replication_server is not included in the config.
DocImpact
Change-Id: Ie9af5bdcdf9241c355e36053ca4adfe49dc35bd0
Implements: blueprint dedicated-replication-network
Enhance internally logged messages to report referer and user-agent.
Pass the referering URL and METHOD between internal servers (when
known), and set the user-agent to be the server type (obj-server,
container-server, proxy-server, obj-updater, obj-replicator,
container-updater, direct-client, etc.) with the process PID. In
conjunction with the transaction ID, it helps to track down which PID
from a given system was responsible for initiating the request and
what that server was working on to make this request.
This has been helpful in tracking down interactions between object,
container and account servers.
We also take things a bit further performaing a bit of refactoring to
consolidate calls to transfer_headers() now that we have a helper
method for constructing them.
Finally we performed further changes to avoid header key duplication
due to string literal header key values and the various objects
representing headers for requests and responses. See below for more
details.
====
Header Keys
There seems to be a bit of a problem with the case of the various
string literals used for header keys and the interchangable way
standard Python dictionaries, HeaderKeyDict() and HeaderEnvironProxy()
objects are used.
If one is not careful, a header object of some sort (one that does not
normalize its keys, and that is not necessarily a dictionary) can be
constructed containing header keys which differ only by the case of
their string literals. E.g.:
{ 'x-trans-id': '1234', 'X-Trans-Id': '5678' }
Such an object, when passed to http_connect() will result in an
on-the-wire header where the key values are merged together, comma
separated, that looks something like:
HTTP_X_TRANS_ID: 1234,5678
For some headers in some contexts, this is behavior is desirable. For
example, one can also use a list of tuples which enumerate the multiple
values a single header should have.
However, in almost all of the contexts used in the code base, this is
not desirable.
This behavior arises from a combination of factors:
1. Header strings are not constants and different lower-case and
title-case header strings values are used interchangably in the
code at times
It might be worth the effort to make a pass through the code to
stop using string literals and use constants instead, but there
are plusses and minuses to doing that, so this was not attempted
in this effort
2. HeaderEnvironProxy() objects report their keys in ".title()"
case, but normalize all other key references to the form
expected by the Request class's environ field
swob.Request.headers fields are HeaderEnvironProxy() objects.
3. HeaderKeyDict() objects report their keys in ".lower()" case,
and normalize all other key references to ".lower()" case
swob.Response.headers fields are HeaderKeyDict() objects.
Depending on which object is used and how it is used, one can end up
with such a mismatch.
This commit takes the following steps as a (PROPOSED) solution:
1. Change HeaderKeyDict() to normalize using ".title()" case to
match HeaderEnvironProxy()
2. Replace standard python dictionary objects with HeaderKeyDict()
objects where possible
This gives us an object that normalizes key references to avoid
fixing the code to normalize the string literals.
3. Fix up a few places to use title case string literals to match
the new defaults
Change-Id: Ied56a1df83ffac793ee85e796424d7d20f18f469
Signed-off-by: Peter Portante <peter.portante@redhat.com>
Towards defining the DiskFile class, or something like it, as an API
for the low level disk acesses, we push the fallocate() system call
down into the DiskFile.mkstemp() method. This allows another
implementation of DiskFile to decide to use or not use fallocate().
Change-Id: Ib4d2ee1f971e4e20e53ca4b41892c5e44ecc88d5
Signed-off-by: Peter Portante <peter.portante@redhat.com>
This patch identifies md5 collisions on objects and sends a 403
from the object server.
Credits for originating this fix are to Michael Factor.
Change-Id: I4f1b32183e2be6bbea56eaff86b9a4c7f440804a
Fix: Bug #1157454
A new configuration parameter is added to /etc/swift/swift.conf
[swift-hash]
swift_hash_path_prefix = 'random unique string'
New installations are advised to set this parameter to a random secret,
which would not be disclosed ouside the organization.
The same secret needs to be used by all swift servers of the same cluster.
Existing installations should set this parameter to an empty string
(the default)
DocImpact
Fixes: Bug #1157454
Change-Id: I63b10d0b7d6dd3f74e0f10bb41b5f240fa03578a
When the number of account/container or container/object replicas are
different, Swift had a few misbehaviors. This commit fixes them.
* On an object PUT/POST/DELETE, if there were 3 object replicas and
only 2 container replicas, then only 2 requests would be made to
object servers. Now, 3 requests will be made, but the third won't
have any X-Container-* headers in it.
* On an object PUT/POST/DELETE, if there were 3 object replicas and 4
container replicas, then only 3/4 container servers would receive
immediate updates; the fourth would be ignored. Now one of the
object servers will receive multiple (comma-separated) values in the
X-Container-* headers and it will attempt to contact both of them.
One side effect is that multiple async_pendings may be written for
updates to the same object. They'll have differing timestamps,
though, so all but the newest will be deleted unread. To trigger
this behavior, you have to have more container replicas than object
replicas, 2 or more of the container servers must be down, and the
headers sent to one object server must reference 2 or more down
container servers; it's unlikely enough and the consequences are so
minor that it didn't seem worth fixing.
The situation with account/containers is analogous, only without the
async_pendings.
Change-Id: I98bc2de93fb6b2346d6de1d764213d7563653e8d
This set of changes reworks the DiskFile class to remove the "extension"
parameter from the put() method, offering the new put_metadata() method with
an optional tombstone keyword boolean, and changes the mkstemp method to only
return the file descriptor.
Reviewing the code it was found that the temporary file name created as a
result of calling DiskFile.mkstemp() was never used by the caller, but the
caller was responsible for passing it back to the DiskFile.put() method. That
seems like too much information is exposed to the caller, when all the caller
requires is the file descriptor to write data into it.
Upon further review, the mkstemp() method was used in three places: PUT, POST
and DELETE method handling. Of those three cases, only PUT requires the file
descriptor, since it is responsible for writing the object contents. For POST
and DELETE, DiskFile only needs to associate metadata with the correct file
name. We abstract the pattern that those two use (once we also refactor the
code to move the fetch of the delete-at metadata, and subsequent
delete-at-update initiation, from under the mkstemp context) by adding the new
put_metadata() method.
As a result, the DiskFile class is then free to do whatever file system
operations it must to meet the API, without the caller having to know more
than just how to write data to a file descriptor. Note that DiskFile itself
key'd off of the '.ts' and '.meta' extensions for its operations, and for that
to work properly, the caller had to know to use those correctly. With this
change, the caller has no knowledge of how the file system is being used to
accomplish data and metadata storage.
See also Question 213796 at:
https://answers.launchpad.net/swift/+question/213796
Change-Id: I267f68e64391ba627b2a13682393bec62600159d
Signed-off-by: Peter Portante <peter.portante@redhat.com>
It is already the case that a DELETE of a deleted object results in a
404, and GET/HEAD/POSTs to both expired and deleted objects result in
404s. However, a DELETE of an expired object resulted in a 202. This
change makes it consistent with the other verbs.
Fixes bug 1076245.
Change-Id: I793e62d72461a4fb9fb3404e10658ddcc4c3a7a6
This change adds multi range retrieval to OpenStack Swift. For non-
segmented data object, a client can use HTTP Range header to specify
multiple ranges to retrieve sections of the data object.
This implementation currently does not support segmented data object
multi range retrieval. When a client sends a multi range request
against a segmented data object, Swift will return HTTP status code
200. Support for segmented data multi range retrieval will be added
in near future.
This implementation is to bring Swift closer to CDMI multi range
data retrieval standard. Once support for segemented data multi
range is added, Swift will be compliant with CDMI standard in
this area.
DocImpact
Change-Id: I4ed1fb0a0a93c037ddb2f551ea62afe447945107
This change replaces WebOb with a mostly compatible local library,
swift.common.swob. Subtle changes to WebOb's API over the years have been a
huge headache. Swift doesn't even run on the current version.
There are a few incompatibilities to simplify the implementation/interface:
* It only implements the header properties we use. More can be easily added.
* Casts header values to str on assignment.
* Response classes ("HTTPNotFound") are no longer subclasses, but partials
on Response, so things like isinstance no longer work on them.
* Unlike newer webob versions, will never return unicode objects.
Change-Id: I76617a0903ee2286b25a821b3c935c86ff95233f
Change previously hard-coded constants into config variables. This
allows deployers to tune their cluster more specifically based on
their needs. For example, a deployment that uses direct swift access
for public content may need to set a larger header value constraint to
allow for the full object name to be represented in the Content-
Disposition header (which browsers check to determine the name of a
downloaded object).
The new settings are set in the [swift-constraints] section of
/etc/swift/swift.conf. Comments were also added to this config file.
Cleaned up swift/common/constraints.py to pass pep8 1.3.3
Funtional tests now require constraints to be defined in /etc/test.conf or in
/etc/swift/swift.conf (in the case of running the functional tests against a
local swift cluster). To have any hope of tests passing, the defined
constraints must match the constraints on the tested cluster.
Removed a ton of "magic numbers" in both unit and functional tests.
Change-Id: Ie4588e052fd158314ddca6cd8fca9bc793311465
fallocate() failures properly return HTTPInsufficientStorage from
object-server before reading from wsgi.input, allowing the proxy
server to error_limit that node.
Change-Id: Idfc293bbab2cff1e508edf58045108ca1ef5cec1
Basically, do all hashing in the replicator without a lock, then
lock briefly to rewrite the hashes file. Retry if someone else has
modified the hashes file in the mean time (which should be rare).
Also, a little refactoring.
Change-Id: I6257a53808d14b567bde70d2d18a9c58cb1e415a
Fixed bug where expirer would get confused by odd deletion times.
Since this has already rolled out, I just capped things at ten 9s, or
Sat Nov 20 17:46:39 2286. I can't wait for the Y2286 world panic. :/
Change-Id: Iba10963faa344a418a1fa573d5c85f4ff864b574
This fixes 500 server crashes caused by requests such as:
curl -X__init__ "http://your-swift-object-server:6000/sda1/p/a/c/o"
Fixes bug 1005903
Change-Id: I6c0ad39a29e07ce5f46b0fdbd11a53a9a1010a04
When an object server was handling concurrent GET or POST requests
from very fast clients, it would starve other connected clients. The
greenthreads responsible for servicing the fast clients would hog the
processor and only rarely yield to another greenthread.
The reason this happens for GET requests is found in
eventlet.greenio.GreenSocket, in the send() method. When you call
.send(data) on a GreenSocket, it immediately calls .send(data) on its
underlying real socket (socket._socketobject). If the real socket
accepts all the data, then GreenSocket.send() returns without yielding
to another greenthread. Only if the real socket failed to accept all
the data (either .send(data) < len(data) or by raising EWOULDBLOCK)
does the GreenSocket yield control.
Under most workloads, this isn't a problem. The TCP connection to
client X can only consume data so quickly, and therefore the
greenthread serving client X will frequently encounter a full socket
buffer and yield control, so no clients starve. However, when there's
a lot of contention for a single object from a large number of fast
clients (e.g. on a LAN connected w/10Gb Ethernet), then one winds up
in a situation where reading from the disk is slower than writing to
the network, and so full socket buffers become rare, and therefore so
do context switches. The end result is that many clients time out
waiting for data.
The situation for PUT requests is analogous; GreenSocket.recv() seldom
encounters EWOULDBLOCK, so greenthreads seldom yield.
This patch calls eventlet.sleep() to yield control after each chunk,
preventing any one greenthread's IO from blocking the hub for very
long.
This code has the flaw that it will greenthread-switch twice when a
send() or recv() does block, but since there isn't a way to find out
if a switch occurred or not, there's no way to avoid it. Since
greenlet switches are quite fast (faster than system calls, which the
object server does a lot of), this shouldn't have a significant
performance impact.
Change-Id: I8549adfb4a198739b80979236c27b76df607eebf
Documentation, including a list of metrics reported and their semantics,
is in the Admin Guide in a new section, "Reporting Metrics to StatsD".
An optional "metric prefix" may be configured which will be prepended to
every metric name sent to StatsD.
Here is the rationale for doing a deep integration like this versus only
sending metrics to StatsD in middleware. It's the only way to report
some internal activities of Swift in a real-time manner. So to have one
way of reporting to StatsD and one place/style of configuration, even
some things (like, say, timing of PUT requests into the proxy-server)
which could be logged via middleware are consistently logged the same
way (deep integration via the logger delegate methods).
When log_statsd_host is configured, get_logger() injects a
swift.common.utils.StatsdClient object into the logger as
logger.statsd_client. Then a set of delegate methods on LogAdapter
either pass through to the StatsdClient object or become no-ops. This
allows StatsD logging to look like:
self.logger.increment('some.metric.here')
and do the right thing in all cases and with no messy conditional logic.
I wanted to use the pystatsd module for the StatsD client, but the
version on PyPi is lagging the git repo (and is missing both the prefix
functionality and timing_since() method). So I wrote my
swift.common.utils.StatsdClient. The interface is the same as
pystatsd.Client, but the code was written from scratch. It's pretty
simple, and the tests I added cover it. This also frees Swift from an
optional dependency on the pystatsd module, making this feature easier
to enable.
There's test coverage for the new code and all existing tests continue
to pass.
Refactored out _one_audit_pass() method in swift/account/auditor.py and
swift/container/auditor.py.
Fixed some misc. PEP8 violations.
Misc test cleanups and refactorings (particularly the way "fake logging"
is handled).
Change-Id: Ie968a9ae8771f59ee7591e2ae11999c44bfe33b2
