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.

1 files changed, 53 insertions, 0 deletions

diff --git a/eventlet/support/psycopg2_patcher.py b/eventlet/support/psycopg2_patcher.py
new file mode 100644
index 0000000..7d9c1d5
--- /dev/null
+++ b/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)