1. 11 Oct, 2022 1 commit
  2. 07 Oct, 2022 1 commit
  3. 05 Oct, 2022 3 commits
  4. 05 Sep, 2022 3 commits
    • Kirill Smelkov's avatar
      fixup! client: Remove support for interoperability with ZEO4 server · 629dd350
      Kirill Smelkov authored
      Fix added test, which verifies that connection to ZEO4 server is rejected, to also pass on py3.
    • Kirill Smelkov's avatar
      client: Remove support for interoperability with ZEO4 server · ee4d7bc7
      Kirill Smelkov authored
      As explained in https://github.com/zopefoundation/ZEO/issues/209 and
      in recent patch titled "Add tests that demonstrates data corruption when
      ZEO5 client is served by ZEO4 server" there is possibility of data
      corruption when ZEO5 client loads data from ZEO4 server.
      A fix for this is not trivial and would have to forward-port
      load-tracking in client from ZEO4 to ZEO5. However, as discussed in
      https://github.com/zopefoundation/ZEO/issues/209, we believe that noone
      is actually using ZEO5.client-ZEO4.server configuration. Thus, given
      that it was already planned to drop ZEO4 support soon, it was decided to
      drop support for ZEO4 server instead of fixing it.
      In this patch:
      - we remove support for testing against ZEO4 server, including removing
        vendored ZEO4 copy.
      - remove support for on-client methods that only ZEO4 server would call.
        This includes the sole method `serialnos`.
      - remove support for connecting to any server besides one that
        interoperates with protocol '5'. ZEO4 used protocol '4'. It is
        explicitly tested by new test that updated ZEO5 client rejects
        connecting to a server that speaks protocol '4'.
      - we do _not_ remove verify_invalidation_queue added by Jim in 2016 via
        5ba506e7 (Fixed a bug handling ZEO4 invalidations during cache
        verification) with the following message:
      	ZEO4 servers can send invalidations out of order with
      	``getInvalidations`` results, presumably because ``getInvalidations``
      	didn't get the commit lock.  ZEO4 clients worked around this (maybe
      	not directly) by queuing invalidations during cache verification.
      	ZEO5 servers don't send invalidations out of order with
      	``getInvalidations`` calls and the ZEO5 client didn't need an
      	invalidation queue, except they do need one to work correctly with
      	ZEO4 servers. :/
        This feature, even-though it is commented as being ZEO4-only, looks
        too risky to be removed in stable branch, especially taking into
        account that in https://github.com/zopefoundation/ZEO/pull/195
        @d-maurer instead of removing, preserved this queue in a similar form:
        I believe it is better be safe than sorry.
    • Kirill Smelkov's avatar
      ClientStorage: Fix thinko in documentation for credentials/username/password/realm · aa08949d
      Kirill Smelkov authored
      d4805a0f (*: Documentation, Cosmetics) documented all credentials and
      username/password/realm as "credentials" and that it is ZEO4-only. It is
      not correct however:
      - username/password/realm are indeed related to basic authentication
        which, in ZEO5, has been _already_ superseded by SSL. Already because
        those parameters, besides the following assert
      	assert not username or password or realm
        are otherwise ignored by ClientStorage constructor.
      - credentials however is ZEO5-only thing added in 2016 by Jim in commit
        dbb066d2 (Added the ability to pass credentials when creating
        client storages) with the following commit message:
          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.
        To my knowledge there is no use of such "credentials" feature, and
        regular ZEO server will just fail in register if any credentials
        object is passed. Still this feature is separate from ZEO4 basic
        authentication support.
      -> Correct the documentation.
  5. 04 Sep, 2022 1 commit
    • Kirill Smelkov's avatar
      Add tests that demonstrates data corruption when ZEO5 client is served by ZEO4 server · 72320df7
      Kirill Smelkov authored
      As explained by "Bug1" in https://github.com/zopefoundation/ZEO/issues/209
      there is a race in between load and invalidate when ZEO5 client works
      wrt ZEO4 server:
          ---- 8< ----
          ZEO5.client - contrary to ZEO4.client - does not account for simultaneous invalidations when working wrt ZEO4.server.
          It shows as e.g.
          (z-dev) kirr@deca:~/src/wendelin/z/ZEO5$ ZEO4_SERVER=1 zope-testrunner -fvvvx --test-path=src -t check_race_load_vs_external
          AssertionError: T1: obj1 (24)  !=  obj2 (23)
          obj1._p_serial: 0x03ea4b6fb05b52cc  obj2._p_serial: 0x03ea4b6faf253855
          zconn_at: 0x03ea4b6fb05b52cc  # approximated as max(serials)
          zstor.loadBefore(obj1, @zconn.at)       ->  serial: 0x03ea4b6fb05b52cc  next_serial: None
          zstor.loadBefore(obj2, @zconn.at)       ->  serial: 0x03ea4b6faf253855  next_serial: 0x03ea4b6fb07def66
          zstor.loadBefore(obj1, @zconn.at)       ->  serial: 0x03ea4b6fb05b52cc  next_serial: 0x03ea4b6fb07def66
          zstor.loadBefore(obj2, @zconn.at)       ->  serial: 0x03ea4b6fb05b52cc  next_serial: 0x03ea4b6fb07def66
          indicating that obj2 was provided to user from the cache that erroneously got stale.
          With [IO trace](f184a1d9) showing message exchange in between client and the server, this looks as:
          # loadBefore issued
          tx (('\x00\x00\x00\x00\x00\x00\x00\x02', '\x03\xeaKo\xaf%8V'), False, 'loadBefore', ('\x00\x00\x00\x00\x00\x00\x00\x02', '\x03\xeaKo\xaf%8V'))
          # received invalidateTransaction
          rx (0, 1, 'invalidateTransaction', ('\x03\xeaKo\xb0[R\xcc', ['\x00\x00\x00\x00\x00\x00\x00\x01', '\x00\x00\x00\x00\x00\x00\x00\x02']))
          # received loadBefore reply but with end_tid=None !!!
          rx (('\x00\x00\x00\x00\x00\x00\x00\x02', '\x03\xeaKo\xaf%8V'), 0, '.reply', ('\x80\x03cZODB.tests.MinPO\nMinPO\nq\x01.\x80\x03}q\x02U\x05valueq\x03K\x17s.', '\x03\xeaKo\xaf%8U', None))
          1) contradicts what @jimfulton [wrote about ZEO4](https://github.com/zopefoundation/ZEO/blob/master/docs/ordering.rst#zeo-4): that there _invalidations are sent in a callback called when the storage lock is held, blocking loads while committing_, and
          2) points out what the bug is:
          Since in ZEO4 loads can be handled while a commit is in progress, ZEO4.client has special care to detect if an `invalidateTransaction` comes in between `load` request and corresponding `.reply` response, and _does not update the cache if invalidateTransaction sneaked in-between_:
          but in ZEO5.client `loadBefore` does not have anything like that
          and thus `invalidateTransaction` sneaked in between `loadBefore` request and
          corresponding `.reply` causes ZEO client cache corruption.
          In the original `check_race_load_vs_external_invalidate` the problem appears
          only sometimes, but the bug happens with ~ 100% probability with the
          following delay injected on the server after `loadBefore`:
          --- a/src/ZEO/tests/ZEO4/StorageServer.py
          +++ b/src/ZEO/tests/ZEO4/StorageServer.py
          @@ -285,7 +285,9 @@ def loadEx(self, oid):
               def loadBefore(self, oid, tid):
                   self.stats.loads += 1
          -        return self.storage.loadBefore(oid, tid)
          +        x = self.storage.loadBefore(oid, tid)
          +        time.sleep(0.1)
          +        return x
               def getInvalidations(self, tid):
                   invtid, invlist = self.server.get_invalidations(self.storage_id, tid)
          so maybe, in addition to normal test runs, it could be also good idea to run
          the whole ZEO testsuite against so-amended storage backend. This way it will be
          similar to how e.g. [races are detected](https://lab.nexedi.com/kirr/go123/blob/070bfdbb/tracing/tracetest/tracetest.go#L76-102) by my [tracetest](https://lab.nexedi.com/kirr/go123/blob/070bfdbb/tracing/tracetest/tracetest.go#L20-73) package.
          ---- 8< ----
      -> Add suggested test to the whole ZEO testsuite. Currently it reliably
      catches the data curruption caused by explained load/invalidate race
      condition and fails as follows:
          (z-dev) kirr@deca:~/src/wendelin/z/ZEO5$ ZEO4_SERVER=1 zope-testrunner -fvvvc -a 100 --test-path=src
          Running .FileStorageLoadDelayedTests tests:
          Failure in test check_race_load_vs_external_invalidate (ZEO.tests.testZEO.FileStorageLoadDelayedTests)
          Traceback (most recent call last):
            File "/usr/lib/python2.7/unittest/case.py", line 329, in run
            File "/home/kirr/src/wendelin/z/ZODB/src/ZODB/tests/racetest.py", line 253, in check_race_load_vs_external_invalidate
              return self._check_race_load_vs_external_invalidate(T2ObjectsInc())
            File "/home/kirr/src/wendelin/z/ZODB/src/ZODB/tests/util.py", line 417, in _
              return f(*argv, **kw)
            File "/home/kirr/src/wendelin/z/ZODB/src/ZODB/tests/racetest.py", line 346, in _check_race_load_vs_external_invalidate
              self.fail('\n\n'.join([_ for _ in failure if _]))
            File "/usr/lib/python2.7/unittest/case.py", line 410, in fail
              raise self.failureException(msg)
          AssertionError: T4: obj1 (19)  !=  obj2 (20)
          obj1._p_serial: 0x03eabd580073db55  obj2._p_serial: 0x03eabd580079a5dd
          zconn_at: 0x03eabd580079a5dd  # approximated as max(serials)
          zstor.loadBefore(obj1, @zconn.at)       ->  serial: 0x03eabd580073db55  next_serial: None
          zstor.loadBefore(obj2, @zconn.at)       ->  serial: 0x03eabd580079a5dd  next_serial: None
          zstor.loadBefore(obj1, @zconn.at)       ->  serial: 0x03eabd580079a5dd  next_serial: None
          zstor.loadBefore(obj2, @zconn.at)       ->  serial: 0x03eabd580079a5dd  next_serial: 0x03eabd5800aff0ee
          T7: obj1 (18)  !=  obj2 (20)
          obj1._p_serial: 0x03eabd580071a011  obj2._p_serial: 0x03eabd580079a5dd
          zconn_at: 0x03eabd580079a5dd  # approximated as max(serials)
          zstor.loadBefore(obj1, @zconn.at)       ->  serial: 0x03eabd580071a011  next_serial: None
          zstor.loadBefore(obj2, @zconn.at)       ->  serial: 0x03eabd580079a5dd  next_serial: None
          zstor.loadBefore(obj1, @zconn.at)       ->  serial: 0x03eabd580079a5dd  next_serial: None
          zstor.loadBefore(obj2, @zconn.at)       ->  serial: 0x03eabd580079a5dd  next_serial: None
      Fortunately added tests do not fail for ZEO5.client-ZEO5.server.
      Running added tests takes more time compared to running regular tests.
      For example the time to run BlobAdaptedFileStorageTests at default
      level=1 takes 19s. To run the same BlobAdaptedFileStorageTests at
      level=2 (thus including check_race_external_invalidate_vs_disconnect
      from https://github.com/zopefoundation/ZODB/pull/368) takes 25s.
      And to run hereby-added FileStorageLoadDelayedTests takes 85s.
      That's why the test is marked as very long via level=10
  6. 02 Sep, 2022 3 commits
  7. 01 Sep, 2022 1 commit
  8. 02 Aug, 2022 1 commit
  9. 01 Jun, 2022 1 commit
  10. 31 May, 2022 1 commit
  11. 30 May, 2022 1 commit
  12. 23 May, 2022 1 commit
    • Kirill Smelkov's avatar
      tests: Drop use of random2 · cc84605e
      Kirill Smelkov authored
      We can use stdlib random module and manually adjust randint to behave
      exactly as before Python3, so that testdata are matched exactly as before.
      Also drop unnecessary `random.seed(42)` in cache_run. It is not needed
      there because random is not used in cache_run at all.
      Based on work of @d-maurer in https://github.com/zopefoundation/ZEO/pull/195 .
  13. 11 Apr, 2022 1 commit
  14. 09 Apr, 2022 2 commits
  15. 07 Apr, 2022 7 commits
  16. 06 Apr, 2022 3 commits
  17. 05 Apr, 2022 1 commit
  18. 31 Mar, 2022 4 commits
  19. 30 Mar, 2022 2 commits
  20. 24 Mar, 2022 2 commits