IOError on Python 2.7 / No such directory __pycache__/

snappy_cffi.py の cffi verify 呼び出し付近から始め、issue で参照されている cffi API および verifier.py の traceback と比較してください。root 権限なしでの Python 2.7 のインストールケースを再現してください。pycache がまだ存在しない場合でも snappy のインポートが失敗しなくなれば完了です。

I try to use snappy which use cffi with a non-root user that can't create the pycache/ dir.
I got :

STDERR: Traceback (most recent call last):
      File "/opt/graphite/pypy/bin/django-admin", line 11, in <module>
        sys.exit(execute_from_command_line())
      File "/opt/graphite/pypy/site-packages/django/core/management/__init__.py", line 353, in execute_from_command_line
        utility.execute()
      File "/opt/graphite/pypy/site-packages/django/core/management/__init__.py", line 302, in execute
        settings.INSTALLED_APPS
      File "/opt/graphite/pypy/site-packages/django/conf/__init__.py", line 55, in __getattr__
        self._setup(name)
      File "/opt/graphite/pypy/site-packages/django/conf/__init__.py", line 43, in _setup
        self._wrapped = Settings(settings_module)
      File "/opt/graphite/pypy/site-packages/django/conf/__init__.py", line 99, in __init__
        mod = importlib.import_module(self.SETTINGS_MODULE)
      File "/opt/pypy/pypy-5.7.1-linux_x86_64-portable/lib-python/2.7/importlib/__init__.py", line 37, in import_module
        __import__(name)
      File "/opt/graphite/webapp/graphite/settings.py", line 160, in <module>
        from graphite.local_settings import *  # noqa
      File "/opt/graphite/webapp/graphite/local_settings.py", line 53, in <module>
        from graphite.local_settings_dynamic import *
      File "/opt/graphite/webapp/graphite/local_settings_dynamic.py", line 1, in <module>
        from biggraphite.plugins import graphite
      File "/opt/graphite/pypy/site-packages/biggraphite/plugins/graphite.py", line 30, in <module>
        from biggraphite import graphite_utils
      File "/opt/graphite/pypy/site-packages/biggraphite/graphite_utils.py", line 17, in <module>
        from biggraphite import utils as bg_utils
      File "/opt/graphite/pypy/site-packages/biggraphite/utils.py", line 22, in <module>
        from biggraphite.drivers import cassandra as bg_cassandra
      File "/opt/graphite/pypy/site-packages/biggraphite/drivers/cassandra.py", line 34, in <module>
        from cassandra import cluster as c_cluster
      File "/opt/graphite/pypy/site-packages/cassandra/cluster.py", line 46, in <module>
        from cassandra.connection import (ConnectionException, ConnectionShutdown,
      File "/opt/graphite/pypy/site-packages/cassandra/connection.py", line 80, in <module>
        import snappy
      File "/opt/graphite/pypy/site-packages/snappy.py", line 50, in <module>
        from snappy_cffi import UncompressError, compress, decompress, \
      File "/opt/graphite/pypy/site-packages/snappy_cffi.py", line 169, in <module>
        ''', libraries=["snappy"])
      File "/opt/pypy/pypy-5.7.1-linux_x86_64-portable/lib_pypy/cffi/api.py", line 438, in verify
        lib = self.verifier.load_library()
      File "/opt/pypy/pypy-5.7.1-linux_x86_64-portable/lib_pypy/cffi/verifier.py", line 113, in load_library
        self._write_source()
      File "/opt/pypy/pypy-5.7.1-linux_x86_64-portable/lib_pypy/cffi/verifier.py", line 202, in _write_source
        with open(self.sourcefilename, "w") as fp:
    IOError: [Errno 2] No such file or directory: '/opt/graphite/pypy/site-packages/__pycache__/_cffi__g762f05ffx6bf5342b.c'

As far as I understand, it calls a deprecated method of cffi (http://cffi.readthedocs.io/en/latest/whatsnew.html?#v1-0-0).
A workaround would be to create pycache/ directory at the installation as root.