Make blocking C library work with gevent
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Latest commit 3639dee Nov 18, 2016



greenify can make Python extension modules having network operations in C code to be compatible with gevent.

greenify uses the Dynamic Function Redirecting technique same as ELF-Hook to patch blocking network operations at runtime, without the need modify the original modules.

Currently greenify only supports ELF format modules, and is tested on Linux.

Build status

  • Branch master : travis_master

Install from source

greenify module is installed using setuptools or pip:

python install


pip install greenify


  1. Active greenify before initiate environment:

    import greenify
  2. Make sure the dynamic module(e.g. libmemcached) is patched before using:

    assert greenify.patch_lib('/usr/lib/')
  3. Import and use the corresponding module, which is now gevent compatible.

Thread Safety

Once activated, the green C functions will, on potentially blocking operation, pass control to gevent's main event loop, which may switch to other ready greenlet which is also in one of the green functions. So, make sure your C code can handle this kind of execution pause and resume. A thread safe program usually is ready for greenify, but remember that all the switches happen in a single thread.


greenify is written and maintained by douban and is licensed under New BSD license.