I'm trying to deploy my app to Heroku. It is using pyOpenSSL, which requires cryptography, which requires libffi. I found a custom buildpack that includes libffi here: https://github.com/mfenniak/heroku-buildpack-python-libffi. However, cryptography cannot seem to find libffi even though it's on LD_LIBRARY_PATH:

$ heroku run bash

heroku> echo $LD_LIBRARY_PATH
/app/.heroku/vendor/lib:/app/vendor/libffi-3.0/lib

heroku> ls /app/vendor/libffi-3.0/lib
libffi-3.0.13  libffi.a  libffi.la  libffi.so  libffi.so.6  libffi.so.6.0.1  pkgconfig

However, I'm not sure LD_LIBRARY_PATH is available during install process, but it is part of the compile step of the buildpack: https://github.com/mfenniak/heroku-buildpack-python-libffi/commit/6ce48d4fd6c55fc3dc462cf6300c17854732b6e2

In general, this buildpack works and I used it previously with bcrypt (https://pypi.python.org/pypi/bcrypt).

Here is the heroku deployment process which fails:

$ git push staging master
Fetching repository, done.
Counting objects: 20, done.
Delta compression using up to 4 threads.
Compressing objects: 100% (11/11), done.
Writing objects: 100% (11/11), 1.71 KiB | 0 bytes/s, done.
Total 11 (delta 9), reused 0 (delta 0)

-----> Fetching custom git buildpack... done
-----> Python app detected
-----> No runtime.txt provided; assuming python-2.7.4.
-----> Using Python runtime (python-2.7.4)
-----> Noticed cffi. Bootstrapping libffi.
PKG_CONFIG_PATH=:/app/vendor/libffi-3.0/lib/pkgconfig/
libffi.pc is in-place at /app/vendor/libffi-3.0/vendor/lib/pkgconfig/libffi.pc, libffi-based builds should work!
-----> Installing dependencies using Pip (1.3.1)
       Obtaining file:///app (from -r requirements.txt (line 1))
         Running setup.py egg_info for package from file:///app

       Downloading/unpacking pyOpenSSL==0.14 (from -r requirements.txt (line 76))
         Running setup.py egg_info for package pyOpenSSL

           no previously-included directories found matching 'doc/_build'
       Downloading/unpacking cryptography==0.2.2 (from -r requirements.txt (line 77))
         Running setup.py egg_info for package cryptography

           Traceback (most recent call last):
             File "<string>", line 16, in <module>
             File "/tmp/pip-build-u45370/cryptography/setup.py", line 113, in <module>
               "build": cffi_build,
             File "/app/.heroku/python/lib/python2.7/distutils/core.py", line 152, in setup
               dist.run_commands()
             File "/app/.heroku/python/lib/python2.7/distutils/dist.py", line 953, in run_commands
               self.run_command(cmd)
             File "/app/.heroku/python/lib/python2.7/distutils/dist.py", line 972, in run_command
               cmd_obj.run()
             File "<string>", line 14, in replacement_run
             File "/app/.heroku/python/lib/python2.7/site-packages/setuptools/command/egg_info.py", line 259, in find_sources
               mm.run()
             File "/app/.heroku/python/lib/python2.7/site-packages/setuptools/command/egg_info.py", line 325, in run
               self.add_defaults()
             File "/app/.heroku/python/lib/python2.7/site-packages/setuptools/command/egg_info.py", line 361, in add_defaults
               sdist.add_defaults(self)
             File "/app/.heroku/python/lib/python2.7/site-packages/setuptools/command/sdist.py", line 199, in add_defaults
               build_py = self.get_finalized_command('build_py')
             File "/app/.heroku/python/lib/python2.7/distutils/cmd.py", line 312, in get_finalized_command
               cmd_obj.ensure_finalized()
             File "/app/.heroku/python/lib/python2.7/distutils/cmd.py", line 109, in ensure_finalized
               self.finalize_options()
             File "/app/.heroku/python/lib/python2.7/site-packages/setuptools/command/build_py.py", line 73, in finalize_options
               _build_py.finalize_options(self)
             File "/app/.heroku/python/lib/python2.7/distutils/command/build_py.py", line 46, in finalize_options
               ('force', 'force'))
             File "/app/.heroku/python/lib/python2.7/distutils/cmd.py", line 298, in set_undefined_options
               src_cmd_obj.ensure_finalized()
             File "/app/.heroku/python/lib/python2.7/distutils/cmd.py", line 109, in ensure_finalized
               self.finalize_options()
             File "/tmp/pip-build-u45370/cryptography/setup.py", line 52, in finalize_options
               from cryptography.hazmat.primitives import constant_time, padding
             File "cryptography/hazmat/primitives/constant_time.py", line 21, in <module>
               _ffi = cffi.FFI()
             File "/app/.heroku/python/lib/python2.7/site-packages/cffi/api.py", line 56, in __init__
               import _cffi_backend as backend
           ImportError: libffi.so.6: cannot open shared object file: No such file or directory
           Complete output from command python setup.py egg_info:
           running egg_info

       creating pip-egg-info/cryptography.egg-info

       writing requirements to pip-egg-info/cryptography.egg-info/requires.txt

       writing pip-egg-info/cryptography.egg-info/PKG-INFO

       writing top-level names to pip-egg-info/cryptography.egg-info/top_level.txt

       writing dependency_links to pip-egg-info/cryptography.egg-info/dependency_links.txt

       writing manifest file 'pip-egg-info/cryptography.egg-info/SOURCES.txt'

       warning: manifest_maker: standard file '-c' not found



       Traceback (most recent call last):

         File "<string>", line 16, in <module>

         File "/tmp/pip-build-u45370/cryptography/setup.py", line 113, in <module>

           "build": cffi_build,

         File "/app/.heroku/python/lib/python2.7/distutils/core.py", line 152, in setup

           dist.run_commands()

         File "/app/.heroku/python/lib/python2.7/distutils/dist.py", line 953, in run_commands

           self.run_command(cmd)

         File "/app/.heroku/python/lib/python2.7/distutils/dist.py", line 972, in run_command

           cmd_obj.run()

         File "<string>", line 14, in replacement_run

         File "/app/.heroku/python/lib/python2.7/site-packages/setuptools/command/egg_info.py", line 259, in find_sources

           mm.run()

         File "/app/.heroku/python/lib/python2.7/site-packages/setuptools/command/egg_info.py", line 325, in run

           self.add_defaults()

         File "/app/.heroku/python/lib/python2.7/site-packages/setuptools/command/egg_info.py", line 361, in add_defaults

           sdist.add_defaults(self)

         File "/app/.heroku/python/lib/python2.7/site-packages/setuptools/command/sdist.py", line 199, in add_defaults

           build_py = self.get_finalized_command('build_py')

         File "/app/.heroku/python/lib/python2.7/distutils/cmd.py", line 312, in get_finalized_command

           cmd_obj.ensure_finalized()

         File "/app/.heroku/python/lib/python2.7/distutils/cmd.py", line 109, in ensure_finalized

           self.finalize_options()

         File "/app/.heroku/python/lib/python2.7/site-packages/setuptools/command/build_py.py", line 73, in finalize_options

           _build_py.finalize_options(self)

         File "/app/.heroku/python/lib/python2.7/distutils/command/build_py.py", line 46, in finalize_options

           ('force', 'force'))

         File "/app/.heroku/python/lib/python2.7/distutils/cmd.py", line 298, in set_undefined_options

           src_cmd_obj.ensure_finalized()

         File "/app/.heroku/python/lib/python2.7/distutils/cmd.py", line 109, in ensure_finalized

           self.finalize_options()

         File "/tmp/pip-build-u45370/cryptography/setup.py", line 52, in finalize_options

           from cryptography.hazmat.primitives import constant_time, padding

         File "cryptography/hazmat/primitives/constant_time.py", line 21, in <module>

           _ffi = cffi.FFI()

         File "/app/.heroku/python/lib/python2.7/site-packages/cffi/api.py", line 56, in __init__

           import _cffi_backend as backend

       ImportError: libffi.so.6: cannot open shared object file: No such file or directory

       ----------------------------------------
       Command python setup.py egg_info failed with error code 1 in /tmp/pip-build-u45370/cryptography
       Storing complete log in /app/.pip/pip.log

 !     Push rejected, failed to compile Python app

To git@heroku.com:my-app-staging.git
 ! [remote rejected] master -> master (pre-receive hook declined)
error: failed to push some refs to 'git@heroku.com:my-app-staging.git'

Update

Strangely enough, if I ssh to a dyno heroku run bash and then pip install pyOpenSSL, then it succeeds. But this doesn't seem to help figuring out what's wrong with the deployment process.

It appears github user kennethjiang had the same problem and forked the custom libffi buildpack with a fix just four days ago.

Here are the relevant changes:

https://github.com/kennethjiang/heroku-buildpack-python-libffi/compare/3bb5fab8213f41411f515f21a6c83ff36c8aa1f2...8ef02

$ heroku config:add BUILDPACK_URL=git://github.com/kennethjiang/heroku-buildpack-python-libffi.git
$ git push heroku master
Initializing repository, done.
Counting objects: 3, done.
Writing objects: 100% (3/3), 260 bytes, done.
Total 3 (delta 0), reused 0 (delta 0)

-----> Fetching custom git buildpack... done
-----> Python app detected
-----> No runtime.txt provided; assuming python-2.7.4.
-----> Preparing Python runtime (python-2.7.4)
-----> Installing Distribute (0.6.36)
-----> Installing Pip (1.3.1)
-----> Noticed cffi. Bootstrapping libffi.
PKG_CONFIG_PATH=:/app/vendor/libffi-3.0/lib/pkgconfig/
libffi.pc is in-place at /app/vendor/libffi-3.0/vendor/lib/pkgconfig/libffi.pc, libffi-based builds should work!
-----> Installing dependencies using Pip (1.3.1)
       Downloading/unpacking pyOpenSSL==0.14 (from -r requirements.txt (line 1))
         Running setup.py egg_info for package pyOpenSSL

           no previously-included directories found matching 'doc/_build'
       Downloading/unpacking cryptography==0.2.2 (from -r requirements.txt (line 2))
         Running setup.py egg_info for package cryptography
           no previously-included directories found matching 'documentation/_build'
           zip_safe flag not set; analyzing archive contents...
           six: module references __file__
           six: module references __path__

           Installed /tmp/pip-build-u24412/cryptography/six-1.6.1-py2.7.egg
           Searching for cffi>=0.8
           Reading http://pypi.python.org/simple/cffi/
           Best match: cffi 0.8.2
           Downloading https://pypi.python.org/packages/source/c/cffi/cffi-0.8.2.tar.gz#md5=37fc88c62f40d04e8a18192433f951ec
           Processing cffi-0.8.2.tar.gz
           Writing /tmp/easy_install-vYzEMy/cffi-0.8.2/setup.cfg
           Running cffi-0.8.2/setup.py -q bdist_egg --dist-dir /tmp/easy_install-vYzEMy/cffi-0.8.2/egg-dist-tmp-KU0RrQ
           cc -c c/check__thread.c -o c/check__thread.o

           Installed /tmp/pip-build-u24412/cryptography/cffi-0.8.2-py2.7-linux-x86_64.egg
...

       Successfully installed pyOpenSSL cryptography six cffi pycparser
       Cleaning up...

-----> Discovering process types
       Procfile declares types -> (none)

-----> Compressing... done, 27.9MB
-----> Launching... done, v5
       http://quiet-atoll-6802.herokuapp.com/ deployed to Heroku

To git@heroku.com:quiet-atoll-6802.git
 * [new branch]      master -> master

来源：https://stackoverflow.com/questions/22415725/problems-with-custom-libffi-heroku-buildpack

标签

python

heroku

cryptography

OpenSSL

libffi

Problems with custom LIBFFI Heroku buildpack

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