- Nothing changed yet.
Drop support for Python 2.7, 3.5, 3.6.
Add support for Python 3.12.
Switch to using async/await directly instead of @coroutine/yield
Drop experimental support for credentials object: the corresponding
ClientStorage.__init__
parametercredentials
is retained but ignored. From now on ZEO supports authentication only via SSL certificates.Note that ZEO 5 never supported authenticating via
username
andpassword
- support for such basic auth was dropped in 2016 before ZEO 5.0 was released.Fix problems with Python 3.12.0b4 (issue 231 <https://github.com/zopefoundation/ZEO/issues/231>_).
Ensure test compatibility with both
ZODB<6
andZODB>=6
by looking for ZODB inherited tests with prefixescheck
(used byZODB<6
) andtest
(used byZODB>=6
) (issue 233 <https://github.com/zopefoundation/ZEO/issues/233>_).
Reimplement and streamline the
asyncio
part of theClientStorage
implementation:- switch from futures with explicit callbacks to async/await-like style
- use standard
asyncio
features to implement timeouts - redesign the API of the class implementing the ZEO client protocol
- significantly improve source documentation and tests
- fix several concurrency bugs
- add optional
cython
based optimization; it speeds up reads but slows down writes. To use it, installcython
(and its dependencies) and runcythonize -i *.pyx
insrc/ZEO/asyncio
.
Remove support for interoperability with ZEO4 server. It turned out that ZEO5 client, contrary to interoperability with ZEO5 server, implements support for interoperability with ZEO4 server incorrectly with concurrency bugs that lead to data corruption. The fix is not trivial and we believe that in 2022 noone actually uses ZEO5.client-ZEO4.server configuration. That's why support for ZEO4 server was dropped rather than fixed.
See issue 209 for details.
If the
zeopack
script cannot connect to a server it sets exit status 1 See #214.Remove
asyncio/mtacceptor
module. It turned out that multi-threaded ZEO5 server has concurrency issues that lead to data corruption. Multi-threaded server mode was already deprecated and scheduled for removal, so the fix is to finally remove it. From now on ZEO server is always single-threaded.See issue 209 for details.
Test ZEO only with the following storages
FileStorage
with server side blobs,FileStorage
with shared blob directory,MappingStorage
(without blobs).Those tests cover all storage features with impact on ZEO: without blobs, with shared blobs and with server side blobs; load, store, two phase commit, undo. Therefore, passing tests for those storages provide high confidence that ZEO works for other properly implemented storages as well. See #198.
Lint the code with flake8
Add support for Python 3.10, 3.11.
Add
ConflictError
to the list of unlogged server exceptions (the client/its application should determine whether it wants them logged).Prevent
no current transaction: tpc_abort()
server log entries. The storage API allowstpc_abort
to be called with an invalid transaction (the call should be ignored in this case) and the server'stpc_vote
relies on this.Change the server's log message label for request exceptions from
Bad request ...
to... raised exception:
, hinting towards a server rather than client problem.See issue 156.
Remove support for
python setup.py test
. It hadn't been working for some time. From now the only supported way to run tests is viazope-testrunner
.
- Remove tests for the
asyncio/mtacceptor
module, it appears unused and presents a maintenance burden. The module will be removed in ZEO version 6. - Remove GitHub Actions testing for Python 3.5, it has reached end of life.
- Add support for Python 3.8 and Python 3.9.
- Add more accurate error handling for
asyncio.CancelledError
. See issue 165. - Fix bug related to blobs stored by
ZEO
#150.
- Ensure
ZEO
satisfies theZODB >= 5.6
requirement thatlastTransaction()
changes only after invalidation processing. Violating this requirement can lead to race conditions and associated data corruption #166. - Add automated tests against the ZODB
master
branch see issue 177. - Fix data corruption due to race between load and external invalidations. See issue 155.
- Improve log message when client cache is out of sync with server. See issue 142.
- Remove support for Python 3.4
- Provide proper CA test certificates to allow the SSL tests succeed for Py3
- Replace deprecated occurrences of
Thread.isAlive()
byThread.is_alive()
See pull request 154. - Include both modified and just created objects into invalidations. See pull request 160.
- Add support for Python 3.7.
- Switch from
msgpack-python
tomsgpack
. Currently a version < 0.6 is required. - Stop calling the deprecated
checkSecure
method when creating aClientStorage
. With ZODB 5.2.2 and above, this issued a warning. With older versions, this could issue a log message, but this was considered a misfeature. See issue 134.
Fixed: The quickstart/ad-hoc/play ZEO server relied on test dependencies. See issue 105.
Disallow passing strings as addresses to ClientStorage under Windows because string addresses are used for unix-domain sockets, which aren't supported on Windows. See issue 107.
Renamed all
async
attributes toasync_
for compatibility with Python 3.7. See issue 104.Fixed to work with some changes made in ZODB 5.4.0.
Client-side updates are included for ZODB 5.4.0 or databases that already had
zodbpickle.binary
OIDs. See issue 113.ZEO now uses pickle protocol 3 for both Python 2 and Python 3. (Previously protocol 1 was used for Python 2.) This matches the change in ZODB 5.4.0.
Fix: ZEO didn't work with a change in ZODB 5.4.0.
(Allow
zodbpickle.binary
to be used in RPC requests, which is necessary for compatibility with ZODB 5.4.0 on Python 2. See issue 107.)
- All classes are new-style classes on Python 2 (they were already new-style on Python 3). This improves performance on PyPy. See issue 86.
- Fixed removing UNIX socket files under Python 2 with ZConfig 3.2.0. See issue 90.
- Added support for serializing ZEO messages using msgpack rather than pickle. This helps pave the way to supporting byteserver, but it also allows ZEO servers to support Python 2 or 3 clients (but not both at the same time) and may provide a small performance improvement.
- Possibly fixed the deprecated and untested zeoctl script.
- Removed zeopasswd, which no longer makes sense given that ZEO authentication was removed, in favor of SSL.
Fixed: ZEO needed changes to work with recent transaction changes.
ZEO now works with the latest versions of ZODB and transaction
- Temporarily require non-quite-current versions of ZODB and transaction until we can sort out some recent breakage.
- Provide much better performance on Python 2.
- Provide better error messages when pip tries to install ZEO on an unsupported Python version. See issue 75.
Packaging-related doc fix
This is a major ZEO revision, which replaces the ZEO network protocol implementation.
New features:
SSL support
Optional client-side conflict resolution.
Lots of mostly internal clean ups.
ClientStorage``server-sync
configuration option andserver_sync
constructor argument to force a server round trip at the beginning of transactions to wait for any outstanding invalidations at the start of the transaction to be delivered.Client disconnect errors are now transient errors. When applications retry jobs that raise transient errors, jobs (e.g. web requests) with disconnect errors will be retried. Together with blocking synchronous ZEO server calls for a limited time while disconnected, this change should allow brief disconnections due to server restart to avoid generating client-visible errors (e.g. 500 web responses).
ClientStorage prefetch method to prefetch oids.
When oids are prefetched, requests are made at once, but the caller doesn't block waiting for the results. Rather, then the caller later tries to fetch data for one of the object ids, it's either delivered right away from the ZEO cache, if the prefetch for the object id has completed, or the caller blocks until the inflight prefetch completes. (No new request is made.)
Dropped features:
The ZEO authentication protocol.
This will be replaced by new authentication mechanims leveraging SSL.
The ZEO monitor server.
Full cache verification.
Client suppprt for servers older than ZODB 3.9
Server support for clients older than ZEO 4.2.0
- Added a
ClientStorage
server-sync
configuration option andserver_sync
constructor argument to force a server round trip at the beginning of transactions to wait for any outstanding invalidations at the start of the transaction to be delivered. - When creating an ad hoc server, a log file isn't created by
default. You must pass a
log
option specifying a log file name. - The ZEO server register method now returns the storage last transaction, allowing the client to avoid an extra round trip during cache verification.
- Client disconnect errors are now transient errors. When applications retry jobs that raise transient errors, jobs (e.g. web requests) with disconnect errors will be retried. Together with blocking synchronous ZEO server calls for a limited time while disconnected, this change should allow brief disconnections due to server restart to avoid generating client-visible errors (e.g. 500 web responses).
- Fixed bugs in using the ZEO 5 client with ZEO 4 servers.
Added the ability to pass credentials when creating client storages.
This is experimental in that passing credentials will cause connections to an ordinary ZEO server to fail, but it facilitates experimentation with custom ZEO servers. Doing this with custom ZEO clients would have been awkward due to the many levels of composition involved.
In the future, we expect to support server security plugins that consume credentials for authentication (typically over SSL).
Note that credentials are opaque to ZEO. They can be any object with a true value. The client mearly passes them to the server, which will someday pass them to a plugin.
Added a ClientStorage prefetch method to prefetch oids.
When oids are prefetched, requests are made at once, but the caller doesn't block waiting for the results. Rather, then the caller later tries to fetch data for one of the object ids, it's either delivered right away from the ZEO cache, if the prefetch for the object id has completed, or the caller blocks until the inflight prefetch completes. (No new request is made.)
Fixed: SSL clients of servers with signed certs didn't load default certs and were unable to connect.
This is a major ZEO revision, which replaces the ZEO network protocol implementation.
New features:
- SSL support
- Optional client-side conflict resolution.
- Lots of mostly internal clean ups.
Dropped features:
The ZEO authentication protocol.
This will be replaced by new authentication mechanims leveraging SSL.
The ZEO monitor server.
Full cache verification.
Client suppprt for servers older than ZODB 3.9
Server support for clients older than ZEO 4.2.0
Changed loadBefore to operate more like load behaved, especially with regard to the load lock. This allowes ZEO to work with the upcoming ZODB 5, which used loadbefore rather than load.
Reimplemented load using loadBefore, thus testing loadBefore extensively via existing tests.
Other changes to work with ZODB 5 (as well as ZODB 4)
Fixed: the ZEO cache loadBefore method failed to utilize current data.
Drop support for Python 2.6 and 3.2.
Fix AttributeError: 'ZEOServer' object has no attribute 'server' when StorageServer creation fails.
- Add support for PyPy.
- Add support for Python 3.4.
- Added a new
ruok
client protocol for getting server status on the ZEO port without creating a full-blown client connection and without logging in the server log. - Log errors on server side even if using multi threaded delay.
- Avoid reading excess random bytes when setting up an auth_digest session.
- Optimize socket address enumeration in ZEO client (avoid non-TCP types).
- Improve Travis CI testing support.
- Assign names to all threads for better runtime debugging.
- Fix "assignment to keyword" error under Py3k in 'ZEO.scripts.zeoqueue'.
- Depend on ZODB >= 4.0.0b2
- Add support for Python 3.2 / 3.3.
First (in a long time) separate ZEO release.
Since ZODB 3.10.5:
- Storage servers now emit Serving and Closed events so subscribers can discover addresses when dynamic port assignment (bind to port 0) is used. This could, for example, be used to update address information in a ZooKeeper database.
- Client storages have a method, new_addr, that can be used to change the server address(es). This can be used, for example, to update a dynamically determined server address from information in a ZooKeeper database.