Merge remote-tracking branch 'origin/asyncio' into server-sync

Conflicts:
	CHANGES.rst

.travis.yml

 language: python
 sudo: false
+cache:
+  pip
+  directories:
+    - eggs
 matrix:
     include:
         - os: linux
@@ -24,9 +28,8 @@ matrix:
           python: 3.5
           env: ZEO4_SERVER=1
 install:
-    - pip install -U setuptools
-    - python bootstrap.py
-    - bin/buildout
+    - pip install -U zc.buildout
+    - buildout
 script:
     - bin/test -v1j99
 notifications:

CHANGES.rst

@@ -6,6 +6,18 @@ Changelog
   the beginning of transactions to wait for any outstanding
   invalidations at the start of the transaction to be delivered.
 
+- 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.
 
 5.0.0a2 (2016-07-30)

README.rst

@@ -180,12 +180,10 @@ Which is a short-hand for::
   connection = db.open()
 
 If you exit the Python process, the storage exits as well, as it's run
-in an in-process thread.  It will leave behind it's configuration and
-log file.  This provides a handy way to get a configuration example.
+in an in-process thread.
 
 You shut down the server more cleanly by calling the stop function
-returned by the ``ZEO.server`` function.  This will remove the
-temporary configuration file.
+returned by the ``ZEO.server`` function.
 
 To have data stored persistently, you can specify a file-storage path
 name using a ``path`` parameter.  If you want blob support, you can

src/ZEO/Exceptions.py

@@ -13,19 +13,26 @@
 ##############################################################################
 """Exceptions for ZEO."""
 
+import transaction.interfaces
+
 from ZODB.POSException import StorageError
 
 class ClientStorageError(StorageError):
-    """An error occurred in the ZEO Client Storage."""
+    """An error occurred in the ZEO Client Storage.
+    """
 
 class UnrecognizedResult(ClientStorageError):
-    """A server call returned an unrecognized result."""
+    """A server call returned an unrecognized result.
+    """
 
-class ClientDisconnected(ClientStorageError):
-    """The database storage is disconnected from the storage."""
+class ClientDisconnected(ClientStorageError,
+                         transaction.interfaces.TransientError):
+    """The database storage is disconnected from the storage.
+    """
 
 class AuthError(StorageError):
-    """The client provided invalid authentication credentials."""
+    """The client provided invalid authentication credentials.
+    """
 
 class ProtocolError(ClientStorageError):
     """A client contacted a server with an incomparible protocol

src/ZEO/StorageServer.py

@@ -222,6 +222,8 @@ class ZEOStorage:
         self.stats = self.server.register_connection(storage_id, self)
         self.lock_manager = self.server.lock_managers[storage_id]
 
+        return self.lastTransaction()
+
     def get_info(self):
         storage = self.storage
 

src/ZEO/tests/forker.py

@@ -139,6 +139,7 @@ def runner(config, qin, qout, timeout=None,
             )
         thread.setDaemon(True)
         thread.start()
+        os.remove(config)
 
         try:
             qin.get(timeout=timeout) # wait for shutdown
@@ -181,7 +182,6 @@ def stop_runner(thread, config, qin, qout, stop_timeout=9, pid=None):
             gc.collect()
 
     thread.join(stop_timeout)
-    os.remove(config)
 
 def start_zeo_server(storage_conf=None, zeo_conf=None, port=None, keep=False,
                      path='Data.fs', protocol=None, blob_dir=None,

src/ZEO/tests/testZEO.py

@@ -831,7 +831,8 @@ Now we'll open a storage server on the data, simulating a restart:
     >>> sv = StorageServer(None, dict(fs=fs))
     >>> s = ZEOStorage(sv, sv.read_only)
     >>> s.notify_connected(FauxConn())
-    >>> s.register('fs', False)
+    >>> s.register('fs', False) == fs.lastTransaction()
+    True
 
 If we ask for the last transaction, we should get the last transaction
 we saved:
@@ -1411,6 +1412,14 @@ call to the server. we'd get some sort of error here.
 
 
 
+    """
+
+def ClientDisconnected_errors_are_TransientErrors():
+    """
+    >>> from ZEO.Exceptions import ClientDisconnected
+    >>> from transaction.interfaces import TransientError
+    >>> issubclass(ClientDisconnected, TransientError)
+    True
     """
 
 if sys.platform.startswith('win'):