import apache_beam metaclass conflict

Question

When I try to import apache beam I get the following error.

>>> import apache_beam
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/home/toor/pfff/local/lib/python2.7/site-packages/apache_beam/__init__.py", line 78, in <module>
    from apache_beam import io
  File "/home/toor/pfff/local/lib/python2.7/site-packages/apache_beam/io/__init__.py", line 21, in <module>
    ...
    from apitools.base.protorpclite import messages
  File "/home/toor/pfff/local/lib/python2.7/site-packages/apitools/base/protorpclite/messages.py", line 1165, in <module>
    class Field(six.with_metaclass(_FieldMeta, object)):
TypeError: Error when calling the metaclass bases
    metaclass conflict: the metaclass of a derived class must be a (non-strict) subclass of the metaclasses of all its bases

I'm working in a new virtual environment in which I have installed apache_beam by installing google-cloud-dataflow with pip as I need the version that is able to run on google cloud platform.

pip install google-cloud-dataflow

I have no idea how to solve this error. For completeness, I'm using python 2.7.12 on bash on ubuntu on Windows. My colleague had the same error when running it on bash on ubuntu on Windows, while directly running on Windows is working fine.

The installed versions of the packages are:

>>> pip freeze
apache-beam==2.1.0
avro==1.8.2
cachetools==2.0.1
certifi==2017.7.27.1
chardet==3.0.4
crcmod==1.7
dill==0.2.6
enum34==1.1.6
funcsigs==1.0.2
future==0.16.0
futures==3.1.1
gapic-google-cloud-pubsub-v1==0.15.4
google-apitools==0.5.11
google-auth==1.1.0
google-auth-httplib2==0.0.2
google-cloud-bigquery==0.25.0
google-cloud-core==0.25.0
google-cloud-dataflow==2.1.0
google-cloud-pubsub==0.26.0
google-gax==0.15.15
googleapis-common-protos==1.5.2
googledatastore==7.0.1
grpc-google-iam-v1==0.11.3
grpcio==1.6.0
httplib2==0.9.2
idna==2.6
mock==2.0.0
oauth2client==3.0.0
pbr==3.1.1
pkg-resources==0.0.0
ply==3.8
proto-google-cloud-datastore-v1==0.90.4
proto-google-cloud-pubsub-v1==0.15.4
protobuf==3.3.0
pyasn1==0.3.5
pyasn1-modules==0.1.4
PyYAML==3.12
requests==2.18.4
rsa==3.4.2
six==1.11.0
urllib3==1.22

Answer 1

Downgrade six to version 1.10.0

pip install six==1.10.0