Transparent caching proxy server for Docker containers, run in a Docker container. It can speed up the dependency-fetching part of your application build process.
First check out the code. Then build with:
sudo docker build -t docker-proxy .
Then run with:
./run.sh
The script will start the container and set up the appropriate routing rules. Your other Docker containers will automatically use the proxy, whether or not they were already running. When you are finished, just press CtrlC to stop the proxy.
NOTE: This project is not designed to be run with a simple docker run
- it
requires run.sh
to be run on the docker host, so it can adjust the
routing rules. You will need to check this code out
and run run.sh
on the host. For OS X, that's on your boot2docker,
Docker Machine or similar host). To start under Docker Machine on OS X:
docker-machine scp run.sh default:/home/docker/run.sh
docker-machine ssh default
sh ./run.sh
run.sh
will fire up a Docker container running Squid, with
appropriate firewall rules in place for transparent proxying. It will also
configure port-based routing on the main host such that any traffic from a
Docker container to port 80 routes via the transparent proxy container. It
requires sudo
access to perform the firewall changes, and it will prompt you
for your password as appropriate.
run.sh
is designed to run in the foreground, because when the
container terminates it needs to remove the rules that were redirecting the
traffic.
If you want to see Squid in operation, you can (in another terminal) attach
to the docker-proxy
container - it is tailing the access log, so will show a
record of requests made.
The proxy server supports HTTPS caching via Squid's SSL Bump feature. To enable it, start with:
./run.sh ssl
The server will decrypt traffic from the server and encrypt it again using its own root certificate. HTTPS connections from your other Docker containers will fail until you install the root certificate. To install it:
- Install the
ca-certificates
package (Debian/Ubuntu images) - Run
detect-proxy.sh
Those steps can be performed in a running container (for testing), or you can
add them to your Dockerfile
. detect-proxy.sh
can be run after you install
your OS packages with apt, because apt shouldn't need HTTPS. However, adding
PPAs with add-apt-repository
will fail until the certificate is installed. See
test/Dockerfile
for an example.
Some programs don't use the OS's primary key store, such as npm
and pip
.
You may need to take extra steps for those programs.
To test HTTPS support, do this in another console after starting the proxy:
cd test
sudo docker build -t test-proxy .
sudo docker run --rm test-proxy
# Should print "All tests passed"
This proxy configuration is intended to be used solely to speed up development of Docker applications. Do not attempt to use this to eavesdrop on other people's connections.
There exists a real possibility this script will break your iptables
or ip
rules in some unexpected way. Be aware that if things go wrong, the potential
exists for all containers to lose the ability to download anything.