Skip to main content

psycogreen – psycopg2 integration with coroutine libraries

The psycogreen package enables psycopg2 to work with coroutine libraries, using asynchronous calls internally but offering a blocking interface so that regular code can run unmodified.

Psycopg offers coroutines support since release 2.2. Because the main module is a C extension it cannot be monkey-patched to become coroutine-friendly. Instead it exposes a hook that coroutine libraries can use to install a function integrating with their event scheduler. Psycopg will call the function whenever it executes a libpq call that may block. psycogreen is a collection of “wait callbacks” useful to integrate Psycopg with different coroutine libraries.

Module psycogreen.eventlet

Eventlet currently supports Psycopg out-of-the-box and psycogreen is not necessary. See the documentation for patching instruction.

If for any reason you want to avoid using Eventlet monkeypatching you can use psycogreen.eventlet.patch_psycopg().

Function psycogreen.eventlet.patch_psycopg()

Enable async processing in Psycopg integrated with the Eventlet events loop. It is performed by registering eventlet_wait_callback() as psycopg2 wait callback.

Function psycogreen.eventlet.eventlet_wait_callback(conn)

A wait callback integrating with Eventlet events loop.

An example script showing concurrent usage of psycopg2 with urlopen() with Eventlet is available in tests/test_eventlet.py.

Module psycogreen.gevent

In order to use psycopg2 asynchronously with gevent you can use psycogreen.gevent.patch_psycopg().

Function psycogreen.gevent.patch_psycopg()

Enable async processing in Psycopg integrated with the gevent events loop. It is performed by registering gevent_wait_callback() as psycopg2 wait callback.

Function psycogreen.gevent.gevent_wait_callback(conn)

A wait callback integrating with gevent events loop.

An example script showing concurrent usage of psycopg2 with urlopen() with gevent is available in tests/test_gevent.py.

uWSGI green threads

Roberto De Ioris is writing uGreen, a green thread implementation on top of the uWSGI async platform.

He has performed some tests using both psycopg2 async support and psycopg2 green support and has reported no problem in their stress tests with both the async styles.

Release files for psycogreen 1.0

For a detailed explanation of source distributions (sdists) and built distributions (wheels), please see the package formats documentation.

Source distribution (sdist)

Source distribution for psycogreen 1.0
File Size Uploaded
psycogreen-1.0.tar.gz 5.1 kB Details

Release files / psycogreen-1.0.tar.gz

Download URL psycogreen-1.0.tar.gz
Size 5.1 kB
Tags Source
SHA-256 checksum
How to use checksums
9acfa6cb5373bcf1eaf27c904d98d59c9f3bb0065cbb005f83ccc45055ace9a1
BLAKE2b-256 checksum
How to use checksums
66299250c6a11822f56a1c2f703e4031d173c5b3725095d3422c11cafcc5427f
Upload date
Uploaded using Trusted Publishing?
What is trusted publishing?
No

Release history Release notifications | RSS feed

1.0.2

1 release file

1.0.1

1 release file

This release

1.0 This release

1 release file

0.0.1

1 release file

Anthropic, PBC Visionary sponsor Bloomberg Visionary sponsor Hudson River Trading Visionary sponsor Meta Visionary sponsor NVIDIA Visionary sponsor Microsoft Sustainability sponsor Depot Continuous Integration AWS Cloud computing and Security Sponsor Datadog Monitoring Fastly CDN Google Download Analytics Sentry Error logging StatusPage Status page