Rails binding.pry usage with docker

rails_binding_pry_on_docker.md

1. Initially install your pry-rails to group development on your apps Gemfile

group :development do
  # ..
  gem 'pry-rails'
  # ..
end

2. Then make sure that your docker-compose.yml contains in the app container the following two:

app:
  ..
  ..
  tty: true
  stdin_open: true

3. Add binding.pry to the desired place you want to have a look on your rails code:

def index
  binding.pry
end

3. Run your docker app container and get the container id

docker-compose up app

and open a seperate terminal to run docker ps and get the container id:

docker ps

and you will get something like the following:

CONTAINER ID        IMAGE               COMMAND                  CREATED             STATUS              PORTS                              NAMES
e5410d059f31        mariadb:10.1        "docker-entrypoint..."   13 days ago         Up 13 days          3306/tcp                           msdsecs_mariadb_1
2557eef7f95c        redis               "docker-entrypoint..."   13 days ago         Up 13 days          6379/tcp                           msdsecs_redis_1
5fd1e9f0d850        msdsadd_sidekiq     "/app/docker_helpe..."   7 weeks ago         Up 42 hours         3000/tcp, 0.0.0.0:6666->6666/tcp   msdsadd_sidekiq_1
a38aaff4b63e        mariadb:10.1        "docker-entrypoint..."   3 months ago        Up 42 hours         3306/tcp                           msdsadd_mariadb_1
f2c0047944dd        redis               "docker-entrypoint..."   3 months ago        Up 42 hours         6379/tcp                           msdsadd_redis_1

With container id in hand, you can attach the terminal to the docker instance:

docker attach e5410d059f31

where e5410d059f31 is the container id of the app. You will get your pry on the attached terminal.