@zoidbergwill if you add some tests to show _trace_db_call working I can review.

Sorry for the delay. Will update this week.

@zoidbergwill, would you update the PR and fix the tests? I can review and get this merged.

Hi @reyang

Thanks, I'll take a look at updating this PR and addressing the comments and fixing the tests this week

I'm not sure where the source of googleapis/nox is, but we need to add Python 3.7 support to it. If someone can link it to me, I'm happy to make a PR to do it.

Also, a caveat of the current Travis CI and Circle CI config, with my current changes which allow people to use Django 1.11 or 2, we're not testing both, which we should.

Whoops, I need to fix Django 1 support.

There are two CI error:

1. code coverage.
2. system test under python 3.6.

Traceback (most recent call last):
  File "/root/repo/.nox/sys-3-6/lib/python3.6/site-packages/django/utils/module_loading.py", line 20, in import_string
    return getattr(module, class_name)
AttributeError: module 'django.contrib.auth.middleware' has no attribute 'SessionAuthenticationMiddleware'

The above exception was the direct cause of the following exception:

Traceback (most recent call last):
  File "/root/repo/.nox/sys-3-6/lib/python3.6/site-packages/django/utils/autoreload.py", line 225, in wrapper
    fn(*args, **kwargs)
  File "/root/repo/.nox/sys-3-6/lib/python3.6/site-packages/django/core/management/commands/runserver.py", line 137, in inner_run
    handler = self.get_handler(*args, **options)
  File "/root/repo/.nox/sys-3-6/lib/python3.6/site-packages/django/contrib/staticfiles/management/commands/runserver.py", line 27, in get_handler
    handler = super().get_handler(*args, **options)
  File "/root/repo/.nox/sys-3-6/lib/python3.6/site-packages/django/core/management/commands/runserver.py", line 64, in get_handler
    return get_internal_wsgi_application()
  File "/root/repo/.nox/sys-3-6/lib/python3.6/site-packages/django/core/servers/basehttp.py", line 42, in get_internal_wsgi_application
    return get_wsgi_application()
  File "/root/repo/.nox/sys-3-6/lib/python3.6/site-packages/django/core/wsgi.py", line 13, in get_wsgi_application
    return WSGIHandler()
  File "/root/repo/.nox/sys-3-6/lib/python3.6/site-packages/django/core/handlers/wsgi.py", line 136, in __init__
    self.load_middleware()
  File "/root/repo/.nox/sys-3-6/lib/python3.6/site-packages/django/core/handlers/base.py", line 34, in load_middleware
    middleware = import_string(middleware_path)
  File "/root/repo/.nox/sys-3-6/lib/python3.6/site-packages/django/utils/module_loading.py", line 24, in import_string
    ) from err
ImportError: Module "django.contrib.auth.middleware" does not define a "SessionAuthenticationMiddleware" attribute/class

@zoidbergwill thanks for working on this! Regarding supporting Python3.7 in CI, and testing against both Django v1 and v2, let's address them separately. I think we need a major improvement on the CI process:

1. Move to Travis CI.
2. Speed up the CI by run virtual environments / tests in parallel.
3. Provide ability to run different framework versions / combinations.
4. Probably separate the core library test and extension test (for example 1: today some of the core lib coverage is relying on test cases in extensions, 2: we cannot detect missing dependencies in the core lib as extensions might install them during test run).

@c24t and I are working on GA release, we would definitely love to make improvements once we get out of the fire.

For this PR, you can focus on v2 test. I think the downside is that we're lacking CI protection for Django v1 for a while.

Sorry, I've been lazily pushing to test stuff on CircleCI because I was lazy to get a GOOGLE_APPLICATION_CREDENTIALS

I'm working on fixing the tests for Django 2.0+ and 1.11. I'll take a look at code coverage today or tomorrow too.

With the other work towards GA and other improvements, do we have issues for all of them? I'd be keen to help.

Problem 1 and 2 would be awesome to improve, since running tests faster is always useful, and having more thorough feedback about what's failing and passing in an overview would be great.

Re: problem 3

Provide ability to run different framework versions / combinations.

I saw #202 covers similar stuff, which would be great for the Django support too. Using a Travis CI matrix would help too.

For problem 4, that sounds useful to improve and fix, also making it easier to run certain system tests with less configuration would be great.

@zoidbergwill you can find all the GA related issues using the GA-Effort tag.

@zoidbergwill would you fix the coverage test failures? Thanks.

@reyang Sorry about the delay. I'll work on fixing the coverage test failures this week.

I'm struggling to get my tests to pass locally, and/or improving the coverage. From my code and tests it should be 100%. I think for some reason my tracer isn't initialising, but I'll have another look later.

Kindly paging @timgraham to take a look too.

What's the policy on Django version support? setup.py has install_requires=[ 'Django >= 1.11.0'] but there's a recent commit (b1075ce) which mentions Django < 1.8!

At this point, Django < 1.11 is unsupported (no security updates) so install_requires is consistent with what I'd recommend. If that's the policy then we can simplify things and remove shims for older Django version support..

I'll do a detailed review after that decision and perhaps send a PR with cleanups that can precede this.

What's the policy on Django version support? setup.py has install_requires=[ 'Django >= 1.11.0'] but there's a recent commit (b1075ce) which mentions Django < 1.8!

We intend to follow https://www.djangoproject.com/download/#supported-versions - the Django version we support in OpenCensus should align with the supported (including LTS) Django versions.

Great. I created #694 with clean ups to remove support for Django < 1.11.

As far as I can tell, the remaining change is this PR don't really "add support for Django 2.0+" but merely add a new feature that requires Django 2.0+. I haven't seen anything obvious in the current code that won't work with Django 2.0, 2.1, or 2.2, but I'll check the tests with those versions.

This PR has been superseded by #697.

Not entirely. There's a a new feature in this PR (see the changes to the middleware) that hasn't been implemented in #697.

@timgraham you're right, there is database part. @zoidbergwill please rebase and reopen the PR if you plan to continue. Thanks!