Scale Dockerfile does not build

[Fizz11]

Description
Dockerfile will not build with a fresh checkout.

Step 26/27 : RUN python manage.py collectstatic --noinput --settings=
 ---> Running in 08ab493b377f
Traceback (most recent call last):
  File "manage.py", line 10, in <module>
    execute_from_command_line(sys.argv)
  File "/usr/lib/python2.7/site-packages/django/core/management/__init__.py", line 364, in execute_from_command_line
    utility.execute()
  File "/usr/lib/python2.7/site-packages/django/core/management/__init__.py", line 338, in execute
    django.setup()
  File "/usr/lib/python2.7/site-packages/django/__init__.py", line 27, in setup
    apps.populate(settings.INSTALLED_APPS)
  File "/usr/lib/python2.7/site-packages/django/apps/registry.py", line 85, in populate
    app_config = AppConfig.create(entry)
  File "/usr/lib/python2.7/site-packages/django/apps/config.py", line 120, in create
    mod = import_module(mod_path)
  File "/usr/lib64/python2.7/importlib/__init__.py", line 37, in import_module
    __import__(name)
  File "/opt/scale/messaging/apps.py", line 16, in <module>
    from .backends.amqp import AMQPMessagingBackend
  File "/opt/scale/messaging/backends/amqp.py", line 11, in <module>
    from kombu import Connection
  File "/usr/lib/python2.7/site-packages/kombu/__init__.py", line 81, in __getattr__
    module = __import__(object_origins[name], None, None, [name])
  File "/usr/lib/python2.7/site-packages/kombu/connection.py", line 28, in <module>
    from .log import get_logger
  File "/usr/lib/python2.7/site-packages/kombu/log.py", line 12, in <module>
    from .utils.encoding import safe_repr, safe_str
  File "/usr/lib/python2.7/site-packages/kombu/utils/__init__.py", line 5, in <module>
    from .compat import fileno, maybe_fileno, nested, register_after_fork
  File "/usr/lib/python2.7/site-packages/kombu/utils/compat.py", line 10, in <module>
    import importlib_metadata
  File "/usr/lib/python2.7/site-packages/importlib_metadata/__init__.py", line 9, in <module>
    import zipp
  File "/usr/lib/python2.7/site-packages/zipp.py", line 12, in <module>
    import more_itertools
  File "/usr/lib/python2.7/site-packages/more_itertools/__init__.py", line 1, in <module>
    from more_itertools.more import *  # noqa
  File "/usr/lib/python2.7/site-packages/more_itertools/more.py", line 340
    def _collate(*iterables, key=lambda a: a, reverse=False):
                               ^
SyntaxError: invalid syntax

Reproduction Steps
Steps to reproduce the problem:

1. clone scale repo
2. docker build .

Expected behavior
image should build sucessfuly

Version and Environment Details

• Client OS: osx

[emimaesmith]

Not just an OSX issue. Same error happening on the gitblab builds (both low and high side). Seems to be caused by more_itertools not supporting Python 2.7 in version 6.0.0 pytest-dev/pytest#4772 (comment).

[Fizz11]

adding in && pip install --upgrade pip \ to line 43 of the dockerfile allows the docker image to build, however now scale will not maintain a connection to MESOS.

2019-08-27 19:01:18 WARNING [scheduler.scheduling.manager(84)] Scheduler not connected to Mesos. Scheduling delayed until connection established.```

loops forever....