Merge lp:~cmiller/desktopcouch/reconnect-on-couch-death into lp:desktopcouch

[Chad Miller]

On couchdb failure, reconnect with logic that starts up the couchdb server again and uses the new port.

[Tim Cole (tcole)]

review: Approve

[Rodrigo Moya (rodrigo-moya)]

review: Approve

[lp:~cmiller/desktopcouch/reconnect-on-couch-death]

169. By Chad Miller on 2010-08-23

Instead of giving python-couchdb view objects to the user, give an object we own that implements reconnecting to the server on errors, and proxies commands otherwise.

170. By Chad Miller on 2010-08-23

Fixes LP: Bug#522538.

=== modified file 'desktopcouch/records/server.py'
--- desktopcouch/records/server.py	2010-02-26 22:23:42 +0000
+++ desktopcouch/records/server.py	2010-08-23 22:54:43 +0000
@@ -49,9 +49,17 @@
     def __init__(self, database, uri=None, record_factory=None, create=False,
                  server_class=OAuthCapableServer, oauth_tokens=None,
                  ctx=desktopcouch.local_files.DEFAULT_CONTEXT):
-        if not uri:
-            port = desktopcouch.find_port(ctx=ctx)
-            uri = "http://localhost:%s" % port
+        self.ctx = ctx
+        self.server_uri = uri
         super(CouchDatabase, self).__init__(
                 database, uri, record_factory=record_factory, create=create,
                 server_class=server_class, oauth_tokens=oauth_tokens, ctx=ctx)
+
+    def _reconnect(self):
+        if not self.server_uri:
+            port = desktopcouch.find_port(ctx=self.ctx)
+            uri = "http://localhost:%s" % port
+        else:
+            uri = self.server_uri
+        super(CouchDatabase, self)._reconnect(uri=uri)
+

=== modified file 'desktopcouch/records/server_base.py'
--- desktopcouch/records/server_base.py	2010-07-02 15:32:25 +0000
+++ desktopcouch/records/server_base.py	2010-08-23 22:54:43 +0000
@@ -22,7 +22,7 @@
 """The Desktop Couch Records API."""
 
 import httplib2, urlparse, cgi, copy
-from time import time
+from time import time, sleep
 import socket
 
 # please keep desktopcouch python 2.5 compatible for now
@@ -170,15 +170,16 @@
                     continue
                 elif isinstance(e, socket.error):
                     logging.warn("Other socket error %s.  Reconnecting.", e)
-                    time.sleep(0.3)  
+                    sleep(0.3)  
                     self._reconnect()
                     continue
                 else:
                     raise
 
-    def _reconnect(self):
+    def _reconnect(self, uri=None):
         logging.info("Connecting to %s." % (self.server_uri or "discovered local port",))
-        self._server = self._server_class(self.server_uri,
+
+        self._server = self._server_class(uri or self.server_uri,
                 **self._server_class_extras)
         if self._database_name not in self._server:
             if self._create:
@@ -432,12 +433,33 @@
     def execute_view(self, view_name, design_doc=DEFAULT_DESIGN_DOCUMENT,
             **params):
         """Execute view and return results."""
+
+        class ReconnectingViewWrapper:
+            """A view from python-couchdb is an object with attributes that
+            cause HTTP requests to be fired off when accessed.  If we wish
+            to be able to reconnect on disappearance of the server, then
+            we must intercept calls from user to python-couchdb."""
+
+            def __init__(wrapper, view, *args, **kwargs):
+                wrapper.view = self.with_reconnects(view, *args, **kwargs)
+
+            def ___call__(wrapper, **options):
+                return self.with_reconnects(wrapper.view.__call__, **options)
+
+            def __iter__(wrapper):
+                return self.with_reconnects(wrapper.view.__iter__)
+
+            def __getitem__(wrapper, key):
+                return self.with_reconnects(wrapper.view.__getitem__, key)
+
         if design_doc is None:
             design_doc = view_name
 
         view_id_fmt = "_design/%(design_doc)s/_view/%(view_name)s"
-        return self.with_reconnects(self.db.view, view_id_fmt % locals(),
-                **params)
+        wrapper = ReconnectingViewWrapper(self.db.view, 
+                                          view_id_fmt % locals(),
+                                          **params)
+        return wrapper
 
     def add_view(self, view_name, map_js, reduce_js,
             design_doc=DEFAULT_DESIGN_DOCUMENT):