Traefik for local development

Ports are nice. There are many of them. But remembering which port is used for which service stops being fun whenever the number of projects increase.

Being able to reference a project by a subdomain to localhost (service-name.localhost) seemed like a good idea. This is one solution to that idea using Traefik.

For extending the Traefik configuration the recommendation is to create a compose.override.yaml file and make the necessary adjustments there.

Adding routers and services

Traefik is configured to use both the Docker and the File provider. Which let's you add a host with Docker labels like this

# a docker-compose example
labels:
  - "traefik.enable=true"
  - "traefik.http.routers.service-1.rule=Host(\`service-1.localhost\`)"

or, for situations where you might have something running that is not containerized, by adding a file in the dynamic directory (you need to create a directory called dynamic in this directory). Maybe something like dynamic/service-2.yml with content like this

http:
  services:
    service-2:
      loadBalancer:
        servers:
          - url: "http://host.docker.internal:{PORT_OF_RUNNING_SERVICE}/"
  routers:
    service-2:
      entryPoints:
        - "http"
      rule: "Host(`service-2.localhost`)"
      # reference the created service
      service: "service-2"

If everything was setup correctly, both service-1.localhost and service-2.localhost should now be good to go.

TLS

For encrypted connections, create a directory called local-certs. Then use mkcert or a similar tool to get your certificates.

Put a file in the dynamic directory like so:

# dynamic/tls.yml
tls:
  certificates:
    - certFile: "/etc/traefik/certs/{certificate-filename}.pem"
      keyFile: "/etc/traefik/certs/{key-filename}.pem"

and add

http:
  routers:
    # [ ... ]
    service-2-tls:
      entryPoints:
        - "https"
      rule: "Host(`service-2.localhost`)"
      service: "service-2"
      tls: {}

if needed or use Traefik labels for a Docker container.

Docker network localdevopment

As part of this setup a Docker network is created. Using this network for services you add makes for easy service to service communication.