Flocker configuration for a Twisted Web-based virtual hosting frontend server container

README

Flocker and Docker configurations for a Twisted Web-based virtual hosting
frontend server container.  The frontend can be linked to other containers to
support multiple HTTP virtual hosts on a single Flocker cluster.

$ ln -sf Dockerfile-proxy Dockerfile
$ docker build -t exarkun/flocker-link-example-proxy:5 .
$ ln -sf Dockerfile-backend Dockerfile
$ docker build -t exarkun/flocker-link-example-backend:2 .
$ flocker-deploy deploy.yml app.yml

app.yml

"version": 1
"applications":
  "proxy":
    "image": "exarkun/flocker-link-example-proxy:5"
    "ports":
    - "internal": 8080
      "external": 8080
    "links":
    - "local_port": 8081
      "remote_port": 8091
      "alias": "PROXY_a.example.com"
    - "local_port": 8082
      "remote_port": 8092
      "alias": "PROXY_b.example.com"
  "kittens":
    "image": "exarkun/flocker-link-example-backend:2"
    "ports":
    - "internal": 8080
      "external": 8091
    "environment":
      "CONTENT": "Kittens!"
  "puppies":
    "image": "exarkun/flocker-link-example-backend:2"
    "ports":
    - "internal": 8080
      "external": 8092
    "environment":
      "CONTENT": "Puppies!"

backend.rpy

from os import environ

from twisted.web.resource import Resource
from twisted.web.server import Site
from twisted.web.static import Data
from twisted.web.proxy import ReverseProxyResource

resource = Resource()
resource.putChild(b"", Data(environ.get(b"CONTENT", b"Default content."), b"text/plain"))

deploy.yml

"version": 1
"nodes":
  "172.16.255.250": ["proxy"]
  "172.16.255.251": ["kittens", "puppies"]

Dockerfile-backend

FROM ubuntu:14.04
MAINTAINER Jean-Paul Calderone, [email protected]

RUN apt-get update
RUN apt-get upgrade -y
RUN apt-get install -y python-twisted-web
RUN apt-get autoremove
RUN apt-get clean

RUN mkdir -p /opt/flocker-links /var/run/flocker-links

ADD backend.rpy /opt/flocker-links/backend.rpy

EXPOSE 8080
WORKDIR /var/run/flocker-links
CMD twistd -n web --resource /opt/flocker-links/backend.rpy

Dockerfile-proxy

FROM ubuntu:14.04
MAINTAINER Jean-Paul Calderone, [email protected]

RUN apt-get update
RUN apt-get upgrade -y
RUN apt-get install -y python-twisted-web
RUN apt-get autoremove
RUN apt-get clean

RUN mkdir -p /opt/flocker-links /var/run/flocker-links

ADD vhoster.rpy /opt/flocker-links/vhoster.rpy

EXPOSE 8080
WORKDIR /var/run/flocker-links
CMD twistd -n web --resource /opt/flocker-links/vhoster.rpy

proxy.rpy

from os import environ
from pprint import pprint

from twisted.web.vhost import NameVirtualHost
from twisted.web.proxy import ReverseProxyResource
from twisted.web.server import Site

root = NameVirtualHost()

pprint(environ)

for k, v in environ.items():
    if k.startswith(b"PROXY_") and k.endswith(b"ADDR"):
       parts = k.split(b"_")
       host = parts[1].lower()
       address = v
       port = int(environ[k[:-len(b"ADDR")] + b"PORT"])

       print 'Adding virtual', host, 'proxying to', repr(address), repr(port)

       root.addHost(host, ReverseProxyResource(address, port, b""))

print 'Finished adding virtual hosts'

resource = Site(root)