Target: Heroku

One of possible deployment targets is Heroku.

While a more known way to deploy to Heroku is to use Procfile, but that comes with a drawback that we can not reuse Nix as a build tool and we would have to come up with a Heroku specific instructions.

Luckily for us Heroku also allows us to push Docker images and Nix on the other hand can also wrap the output in a Docker image format. More below…

Manual deployment

While we have an automated and regular (weekly) way how to deploy efficiently all of our projects to all targets, sometimes it is desired to have an option to manually deploy to only a single target.

To do a manual deployment you need to:

  • ensure that you have all requirements installed
  • checkout the revision you want to deploy
  • and run ./please tools deploy:HEROKU ...

You can check all possible options of this command by appending --help at the end. An example command to deploy treestatus/api project to production environment would be:

$ ./please tools deploy:HEROKU treestatus/api \
        --heroku-app="releng-production-treestatus" \
        --extra-attribute=".deploy.production" \
        --taskcluster-secret="" \
        --taskcluster-client-id="..." \

You will need to have a Taskcluster client with the following scopes:

  • assume:hook-id:project-releng/services-production-*
  • hooks:modify-hook:project-releng/services-production-*
  • queue:create-task:aws-provisioner-v1/releng-svc*

I suggest you create a custom (and temporary) client via Takcluster’s Client Manager, that should generate above needed --taskcluster-client-id and --taskcluster-access-token.

Testing docker image locally

Above mentioned command would internally build docker image. It is also possible to build docker image and run it locally.

To build docker image for treestatus/api project do:

$ ./please tools build treestatus/api \
$ realpath tmp/result-build-treestatus-api-1

A symlink to Docker image is create at tmp/result-build-treestatus-api-1 location.

Now all you need to do is load image and run it:

$ cat tmp/result-build-treestatus-api-1 | docker load
$ docker images
mozilla-treestatus-api   1.0.0   7a7c7882c4a3   47 years ago   262 MB
$ docker run \
    -e \