Running Django on Docker: a workflow and code
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The document outlines a workflow for running Django applications on Docker, emphasizing the importance of reproducible deployments and immutable external storage. It includes detailed steps for building Docker images, handling database migrations, starting application servers, and configuring logging settings. Additionally, it introduces tools like 'forklift' for managing application dependencies and troubleshooting within containers.
![VOLUME ["/static", "/storage"]
RUN mkdir -p /static /storage &&
chown -R app /static /storage](https://image.slidesharecdn.com/runningdjangoondockeraworkflowandcode-140801231545-phpapp02/85/Running-Django-on-Docker-a-workflow-and-code-19-320.jpg)
![RUN echo "__version__ = '`git describe`'"
> myapp/__version__.py
RUN ./invoke.sh install
ENTRYPOINT ["./invoke.sh"]
EXPOSE 8000](https://image.slidesharecdn.com/runningdjangoondockeraworkflowandcode-140801231545-phpapp02/85/Running-Django-on-Docker-a-workflow-and-code-20-320.jpg)
![invoke.sh
#!/bin/sh
# default parameters
: ${APP_USER:=app}
: ${WEB_CONCURRENCY:=1}
export WEB_CONCURRENCY
if [ "x$(whoami)" != "x$APP_USER" ]; then
# ensure we own our storage
chown -R "$APP_USER" /static /storage
# Call back into ourselves as the app user
exec sudo -sE -u "$APP_USER" -- "$0" "$@"
else](https://image.slidesharecdn.com/runningdjangoondockeraworkflowandcode-140801231545-phpapp02/85/Running-Django-on-Docker-a-workflow-and-code-21-320.jpg)
![from dj_database_url import parse
DATABASES = {
'default': parse(os.environ['DB_DEFAULT_URL']),
}](https://image.slidesharecdn.com/runningdjangoondockeraworkflowandcode-140801231545-phpapp02/85/Running-Django-on-Docker-a-workflow-and-code-24-320.jpg)
![# Logging is complex
LOGGING['handlers']['logstash'] = {
'level': 'DEBUG' if DEBUG else 'INFO',
'class': 'logging.handlers.SysLogHandler',
'address': (os.environ['SYSLOG_SERVER'],
int(os.environ['SYSLOG_PORT']))
'socktype': socket.SOCK_STREAM
if os.environ['SYSLOG_PROTO'] ==
else socket.SOCK_DGRAM,
}](https://image.slidesharecdn.com/runningdjangoondockeraworkflowandcode-140801231545-phpapp02/85/Running-Django-on-Docker-a-workflow-and-code-25-320.jpg)
![forklift.services.memcache
@register('memcache')
class Memcache(Service):
providers = ('localhost', 'container')
DEFAULT_PORT = 11211
def __init__(self, key_prefix='', hosts=None):
self.key_prefix = key_prefix
self.hosts = hosts or []](https://image.slidesharecdn.com/runningdjangoondockeraworkflowandcode-140801231545-phpapp02/85/Running-Django-on-Docker-a-workflow-and-code-40-320.jpg)
Running Django on Docker: a workflow and code
- 1. Running Django on Docker a workflow and code Alexey Kotlyarov • Danielle Madeley
- 2. The problem
- 5. A diverse world of applications
- 9. Base OS (Debian bootstrap) App dependencies (Python, libs) Built application Transient runtime Immutable External Storage
- 10. But there's no standards! 12factor.net is a must read
- 11. Pallet An interface for Docker containers github.com/infoxchange/pallet
- 12. What's in deploy? database migrations loading fixtures install static content to static web server (CDN, Ceph, nginx, etc.)
- 13. What's in serve? Start app server Starting supporting services, e.g. Celery
- 14. Keep it lean
- 15. $ docker build .
- 16. Dockerfile FROM debian/ubuntu/fedora/etc. RUN apt-get -qq update && apt-get -qq install git mercurial python python-virtualenv python-pip ...
- 17. RUN useradd -d /app -r app WORKDIR /app
- 18. ADD requirements.txt /app/requirements.txt RUN virtualenv python_env && . python_env/bin/activate && pip install -r requirements.txt ADD . /app
- 19. VOLUME ["/static", "/storage"] RUN mkdir -p /static /storage && chown -R app /static /storage
- 20. RUN echo "__version__ = '`git describe`'" > myapp/__version__.py RUN ./invoke.sh install ENTRYPOINT ["./invoke.sh"] EXPOSE 8000
- 21. invoke.sh #!/bin/sh # default parameters : ${APP_USER:=app} : ${WEB_CONCURRENCY:=1} export WEB_CONCURRENCY if [ "x$(whoami)" != "x$APP_USER" ]; then # ensure we own our storage chown -R "$APP_USER" /static /storage # Call back into ourselves as the app user exec sudo -sE -u "$APP_USER" -- "$0" "$@" else
- 22. else . ./startenv case "$1" in deploy) shift 1 # consume command from $@ ./manage.py migrate "$@" ;; serve) gunicorn -w "$WEB_CONCURRENCY" -b 0.0.0.0:8000 "${APP}.wsgi:applicatio ;; *) ./manage.py "$@" ;; esac fi
- 24. from dj_database_url import parse DATABASES = { 'default': parse(os.environ['DB_DEFAULT_URL']), }
- 25. # Logging is complex LOGGING['handlers']['logstash'] = { 'level': 'DEBUG' if DEBUG else 'INFO', 'class': 'logging.handlers.SysLogHandler', 'address': (os.environ['SYSLOG_SERVER'], int(os.environ['SYSLOG_PORT'])) 'socktype': socket.SOCK_STREAM if os.environ['SYSLOG_PROTO'] == else socket.SOCK_DGRAM, }
- 26. # Trust our nginx server USE_X_FORWARDED_HOST = True SECURE_PROXY_SSL_HEADER = ('HTTP_X_FORWARDED_PROTO', MY_SITE_DOMAIN = os.environ.get('SITE_DOMAIN') if MY_SITE_DOMAIN: ALLOWED_HOSTS = (MY_SITE_DOMAIN,)
- 27. IXDjango pallet configuration for Django pip install IXDjango from ixdjango.docker_settings import * github.com/infoxchange/ixdjango
- 30. docker run -p 8000:8000 -e DB_DEFAULT_URL=postgres://user:pass@db3:5432/mya -e SITE_DOMAIN=myapp-staging.company.com -e SITE_PROTO=https -e ENVIRONMENT=staging -e ELASTICSEARCH_URLS=http://elastic-1:9200/myapp -v /mnt/docker-storage/myapp:/storage -h WHY_ARE_YOU_STILL_READING_THIS myapp serve
- 31. Urgh!
- 32. Forklift a tool for loading pallets github.com/infoxchange/docker-forklift
- 34. $ forklift myapp serve
- 36. $ forklift ./invoke.sh serve $ forklift ./manage.py test
- 37. Poking around inside containers (aka troubleshooting)
- 38. $ forklift --mount-root /tmp/myapp myapp sshd
- 40. forklift.services.memcache @register('memcache') class Memcache(Service): providers = ('localhost', 'container') DEFAULT_PORT = 11211 def __init__(self, key_prefix='', hosts=None): self.key_prefix = key_prefix self.hosts = hosts or []
- 41. def environment(self): return { 'MEMCACHE_HOSTS': '|'.join(self.hosts), 'MEMCACHE_PREFIX': self.key_prefix, } def available(self): """ Check whether memcache is available """ ...
- 42. @classmethod def localhost(cls, application_id): """The default memcached provider""" return cls( key_prefix=application_id, hosts=['localhost:{0}'.format(cls.DEFAULT
- 43. @classmethod @transient_provider def container(cls, application_id): """Memcached provided by a container.""" container = ensure_container( image='fedora/memcached', port=cls.DEFAULT_PORT, application_id=application_id, ) return cls( key_prefix=application_id, hosts=['localhost:{0}'.format(container.p )
- 45. forklift --cleanroom myapp test