forwarder

Small Docker image purely for forwarding with HTTP 301 code. Published on Docker Hub as tacov/forwarder.

Listens to port 80 and responds with a redirect to https://${REDIRECT_TO}, preserving the query.

Relevant usecase: running a site example.com on Google Cloud Run, we need a way to capture www.example.com traffic as well. This cannot be handled on DNS level, nor easily within Google Cloud Run, nor is it good practice to hardcode it in the actual application. Therefore, a for-purpose "application" must be used. Since GCR handles SSL, we do not need to worry about that. Listen to internal http requests, send to https.

How to use

To build and run locally:

docker build . -t my-forwarder
docker run -e REDIRECT_TO=example.com -p80:80 my-forwarder

To just use on your machine

docker run -e REDIRECT_TO=example.com -p80:80 tacov/forwarder

or in docker-compose.yml

services:
  my-forwarder:
    image: tacov/forwarder
    ports:
      - 80:80
    environment:
      REDIRECT_TO: example.com

To push to your Google Cloud Run environment (see also their docs)

docker pull tacov/forwarder
docker tag tacov/forwarder [LOCATION]-docker.pkg.dev/[PROJECT-ID]/[REPOSITORY]/forwarder
docker push [LOCATION]-docker.pkg.dev/[PROJECT-ID]/[REPOSITORY]/forwarder

See also

https://hub.docker.com/_/nginx/ --> Using environment variables in nginx configuration