Added Daniele Varrazzo's green-psycopg2 patch. Untested in the case where the module is actually present, but verified that it's a no-op if not installed.

eventlet/patcher.py

@@ -136,7 +136,7 @@ def monkey_patch(**on):
 
     It's safe to call monkey_patch multiple times.
     """
-    accepted_args = set(('os', 'select', 'socket', 'thread', 'time'))
+    accepted_args = set(('os', 'select', 'socket', 'thread', 'time', 'psycopg'))
     default_on = on.pop("all",None)
     for k in on.iterkeys():
         if k not in accepted_args:
@@ -167,6 +167,13 @@ def monkey_patch(**on):
     if on['time'] and not already_patched.get('time'):
         modules_to_patch += _green_time_modules()
         already_patched['time'] = True
+    if on['psycopg'] and not already_patched.get('psycopg'):
+        try:
+            from eventlet.support import psycopg2_patcher
+            psycopg2_patcher.make_psycopg_green()
+        except ImportError:
+            pass
+        already_patched['psycopg'] = True
 
     for name, mod in modules_to_patch:
         orig_mod = sys.modules.get(name)
@@ -201,6 +208,7 @@ def _green_time_modules():
     from eventlet.green import time
     return [('time', time)]
 
+
 if __name__ == "__main__":
     import sys
     sys.argv.pop(0)

eventlet/support/psycopg2_patcher.py

@@ -0,0 +1,53 @@
+"""A wait callback to allow psycopg2 cooperation with eventlet.
+
+Use `make_psycopg_green()` to enable eventlet support in Psycopg.
+"""
+
+# Copyright (C) 2010 Daniele Varrazzo <daniele.varrazzo@gmail.com>
+# and licensed under the MIT license:
+# 
+# Permission is hereby granted, free of charge, to any person obtaining a copy
+# of this software and associated documentation files (the "Software"), to deal
+# in the Software without restriction, including without limitation the rights
+# to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+# copies of the Software, and to permit persons to whom the Software is
+# furnished to do so, subject to the following conditions:
+# 
+# The above copyright notice and this permission notice shall be included in
+# all copies or substantial portions of the Software.
+# 
+# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+# THE SOFTWARE.
+
+import psycopg2
+from psycopg2 import extensions
+
+from eventlet.hubs import trampoline
+
+def make_psycopg_green():
+    """Configure Psycopg to be used with eventlet in non-blocking way."""
+    if not hasattr(extensions, 'set_wait_callback'):
+        raise ImportError(
+            "support for coroutines not available in this Psycopg version (%s)"
+            % psycopg2.__version__)
+
+    extensions.set_wait_callback(eventlet_wait_callback)
+
+def eventlet_wait_callback(conn, timeout=-1):
+    """A wait callback useful to allow eventlet to work with Psycopg."""
+    while 1:
+        state = conn.poll()
+        if state == extensions.POLL_OK:
+            break
+        elif state == extensions.POLL_READ:
+            trampoline(conn.fileno(), read=True)
+        elif state == extensions.POLL_WRITE:
+            trampoline(conn.fileno(), write=True)
+        else:
+            raise psycopg2.OperationalError(
+                "Bad result from poll: %r" % state)

tests/patcher_test.py

@@ -171,15 +171,15 @@ print "already_patched", ",".join(sorted(patcher.already_patched.keys()))
 
     def test_boolean(self):
         self.assert_boolean_logic("patcher.monkey_patch()",
-                                         'os,select,socket,thread,time')
+                                         'os,psycopg,select,socket,thread,time')
 
     def test_boolean_all(self):
         self.assert_boolean_logic("patcher.monkey_patch(all=True)",
-                                         'os,select,socket,thread,time')
+                                         'os,psycopg,select,socket,thread,time')
 
     def test_boolean_all_single(self):
         self.assert_boolean_logic("patcher.monkey_patch(all=True, socket=True)",
-                                         'os,select,socket,thread,time')
+                                         'os,psycopg,select,socket,thread,time')
 
     def test_boolean_all_negative(self):
         self.assert_boolean_logic("patcher.monkey_patch(all=False, "\
@@ -197,12 +197,12 @@ print "already_patched", ",".join(sorted(patcher.already_patched.keys()))
 
     def test_boolean_negative(self):
         self.assert_boolean_logic("patcher.monkey_patch(socket=False)",
-                                         'os,select,thread,time')
+                                         'os,psycopg,select,thread,time')
 
     def test_boolean_negative2(self):
         self.assert_boolean_logic("patcher.monkey_patch(socket=False,"\
                                       "time=False)",
-                                         'os,select,thread')
+                                         'os,psycopg,select,thread')
 
     def test_conflicting_specifications(self):
         self.assert_boolean_logic("patcher.monkey_patch(socket=False, "\