Automating login and logout

The following example demonstrates adding a couple of new tasks called login and logout, which will perform these actions using the Docker client:

.PHONY: test release clean version login logout

export APP_VERSION ?= $(shell git rev-parse --short HEAD)

version:
  @ echo '{"Version": "$(APP_VERSION)"}'

login:
    $$(aws ecr get-login --no-include-email)

logout:
    docker logout https://385605022855.dkr.ecr.us-east-1.amazonaws.com

test:
    docker-compose build --pull release
    docker-compose build
    docker-compose run test

release:
    docker-compose up --abort-on-container-exit migrate
    docker-compose run app python3 manage.py collectstatic --no-input
    docker-compose up --abort-on-container-exit acceptance
    @ echo App running at http://$$(docker-compose port app 8000 | sed s/0.0.0.0/localhost/g)

clean:
    docker-compose down -v
    docker images -q -f dangling=true -f label=application=todobackend | xargs -I ARGS docker rmi -f ARGS

Notice that the login task uses a double dollar sign ($$), which is required as Make uses single dollar signs to define Make variables. When you specify a double dollar sign, Make will pass a single dollar sign to the shell, which in this case will ensure a bash command substitution is executed.

When logging out with the logout task, notice that you need to specify the Docker registry, otherwise the Docker client assumes the default public Docker Hub registry.

With these tasks in place, you can now easily log out and log in of ECR using the make logout and make login commands:

> make logout
docker logout https://385605022855.dkr.ecr.us-east-1.amazonaws.com
Removing login credentials for 385605022855.dkr.ecr.us-east-1.amazonaws.com

> make login
$(aws ecr get-login --no-include-email)
WARNING! Using --password via the CLI is insecure. Use --password-stdin.
Login Succeeded