Add Dockerfile and docker-compose.yml

[tobiasmcnulty]

• Add Alpine Linux-based Dockerfile with optimizations to minimize the image size
• Switch to uWSGI (can be configured entirely via environment variables) and includes a built-in HTTP proxy which survives better "in the wild" (see http://uwsgi-docs.readthedocs.io/en/latest/HTTP.html#can-i-use-uwsgi-s-http-capabilities-in-production)
• Refactor the Heroku-specific requirements and settings files into "production" files; the latter uses environment variables to keep sane defaults but allow customization

To do:

• Add defaults for S3 uploaded media (per readme.md) to production settings file
• Add .travis.yml for testing Docker image build (can be expanded later to run unit tests, if any)

[daaray]

Two things:

1. https://github.com/tobiasmcnulty/bakerydemo/blob/docker/app.json#L7 needs to be changed to "DJANGO_SETTINGS_MODULE": "bakerydemo.settings.production"

2. I cloned this demo, checked out the docker branch, and ran docker-compose up --build. I get the following error, any thoughts?

If I tweak bakerydemo.settings.production and provide a default for SECRET_KEY, the setup steps work. Not ideal, any other thoughts?

SECRET_KEY = os.getenv('DJANGO_SECRET_KEY', 'changeme')

[daaray]

• Confirming latest edits resolved my issues
• Confirming deploy to heroku button build works with this PR

[tobiasmcnulty]

Thanks! I'll get S3 in there and then it should be ready to merge. Do you know if there are plans to add Travis (or another CI)? We could also include a smoke test for the docker image.

[daaray]

We definitely did not get so far as to have a discussion regarding CI, but I think that it is an excellent idea, given that we have multiple contributors.

[tobiasmcnulty]

@daaray I could not get S3 working with boto3, but this configuration seems to work. Might have been because I'm relying on AWS_AUTO_CREATE_BUCKET. Did boto3 work for you?

[daaray]

Yes, I did utilize boto3, per the blog post I derived the material from: https://wagtail.io/blog/amazon-s3-for-media-files/

[tobiasmcnulty]

This appears to be the issue: jschneier/django-storages#268

Given this and the number of other S3Boto3Storage issues recently resolved and/or still outstanding in django-storages, I suggest we stick with boto2 for now.

[daaray]

Tested latest (pre Travis commits):

• Docker build 👍
• Heroku w/o S3 👍
• Heroku w S3 👍

🚢 when you are happy with the Travis config.

[jasjukaitis]

Hey there! I just came across this issue and experienced the same killed by signal 11 when using django-storages in Docker. I've used python:3.6-alpine and then retried it with python:3.6-jessie and suddenly it works. Don't know why, but better to use boto3 than boto. Just fyi :)

[kaedroho]

Alpine linux doesn't have glibc so the Python implementation is probably linked against musl instead. I guess that has something to do with the crash you're getting. It looks like a lot of Python projects run into an issue with musl's small default stack size (80kb) leading to segfaults.

[gasman]

Yep, we've seen issues with Alpine Linux before: wagtail/wagtail#3438. The conclusion I came to then was that the default system config was too resource-constrained for us to sensibly support.