TypeError when generating Rails.application.secrets.jws_private_key

This happens when the GITLAB_SECRETS_* environment variables are set to strings consisting strictly of numbers, e.g. 12345678901234567890.

I discovered this during development when I was too lazy to generate some realistic placeholder values. In production scenarios you would probably generate some proper values and never encounter this issue. But I spent some time working out the reason for this one, and a fix could probably save time for someone else who is also lazy. I understand if this issue won't be prioritized :D

Steps to reproduce:

❯ mkdir /tmp/docker-gitlab-bug-report
❯ cd /tmp/docker-gitlab-bug-report

# Fetch `docker-compose.yml` as mentioned in the README.md
❯ wget https://raw.githubusercontent.com/sameersbn/docker-gitlab/master/docker-compose.yml
--2017-04-14 11:17:07--  https://raw.githubusercontent.com/sameersbn/docker-gitlab/master/docker-compose.yml
Resolving raw.githubusercontent.com (raw.githubusercontent.com)... 151.101.88.133
Connecting to raw.githubusercontent.com (raw.githubusercontent.com)|151.101.88.133|:443... connected.
HTTP request sent, awaiting response... 200 OK
Length: 3836 (3.7K) [text/plain]
Saving to: ‘docker-compose.yml’

docker-compose.yml                           100%[============================================================================================>]   3.75K  --.-KB/s    in 0s

2017-04-14 11:17:07 (18.2 MB/s) - ‘docker-compose.yml’ saved [3836/3836]

# Set values of services.gitlab.environment.GITLAB_SECRETS_* to large numbers
❯ sed -i -e 's/long-and-random-alphanumeric-string/123456789012345678901234567890/g' docker-compose.yml

# Try to bring up the services, but fail
❯ docker-compose up
dockergitlabbugreport_postgresql_1 is up-to-date
dockergitlabbugreport_redis_1 is up-to-date
Starting dockergitlabbugreport_gitlab_1
Attaching to dockergitlabbugreport_postgresql_1, dockergitlabbugreport_redis_1, dockergitlabbugreport_gitlab_1
gitlab_1      | Initializing logdir...
gitlab_1      | Initializing datadir...
postgresql_1  | Initializing datadir...
postgresql_1  | Initializing certdir...
postgresql_1  | Initializing logdir...
postgresql_1  | Initializing rundir...
postgresql_1  | Setting resolv.conf ACLs...
postgresql_1  | Creating database user: gitlab
postgresql_1  | Creating database: gitlabhq_production...
postgresql_1  | ‣ Loading pg_trgm extension...
postgresql_1  | ‣ Granting access to gitlab user...
postgresql_1  | Starting PostgreSQL 9.6...
postgresql_1  | LOG:  database system was shut down at 2017-04-14 02:19:50 UTC
postgresql_1  | LOG:  MultiXact member wraparound protections are now enabled
postgresql_1  | LOG:  database system is ready to accept connections
postgresql_1  | LOG:  autovacuum launcher started
redis_1       | Starting redis-server...
redis_1       | [1] 14 Apr 02:19:47.563 # Server started, Redis version 2.8.4
redis_1       | [1] 14 Apr 02:19:47.563 # WARNING overcommit_memory is set to 0! Background save may fail under low memory condition. To fix this issue add 'vm.overcommit_memory = 1' to /etc/sysctl.conf and then reboot or run the command 'sysctl vm.overcommit_memory=1' for this to take effect.
gitlab_1      | Installing configuration templates...
gitlab_1      | Configuring gitlab...
gitlab_1      | Configuring gitlab::database
gitlab_1      | Configuring gitlab::redis
gitlab_1      | Configuring gitlab::secrets...
gitlab_1      | Configuring gitlab::sidekiq...
gitlab_1      | Configuring gitlab::gitlab-workhorse...
gitlab_1      | Configuring gitlab::unicorn...
gitlab_1      | Configuring gitlab::timezone...
gitlab_1      | Configuring gitlab::rack_attack...
gitlab_1      | Configuring gitlab::ci...
gitlab_1      | Configuring gitlab::artifacts...
gitlab_1      | Configuring gitlab::lfs...
gitlab_1      | Configuring gitlab::mattermost...
gitlab_1      | Configuring gitlab::project_features...
gitlab_1      | Configuring gitlab::oauth...
gitlab_1      | Configuring gitlab::ldap...
gitlab_1      | Configuring gitlab::backups...
gitlab_1      | Configuring gitlab::backups::schedule...
gitlab_1      | Configuring gitlab::registry...
gitlab_1      | Configuring gitlab::pages...
gitlab_1      | Configuring gitlab-shell...
gitlab_1      | Configuring nginx...
gitlab_1      | Configuring nginx::gitlab...
gitlab_1      | Setting up GitLab for firstrun. Please be patient, this could take a while...
gitlab_1      | Missing Rails.application.secrets.jws_private_key for production environment. The secret will be generated and stored in config/secrets.yml.
gitlab_1      | rake aborted!
gitlab_1      | TypeError: no implicit conversion of Bignum into String
gitlab_1      | /home/git/gitlab/vendor/bundle/ruby/2.3.0/gems/activesupport-4.2.8/lib/active_support/key_generator.rb:21:in `pbkdf2_hmac_sha1'
gitlab_1      | /home/git/gitlab/vendor/bundle/ruby/2.3.0/gems/activesupport-4.2.8/lib/active_support/key_generator.rb:21:in `generate_key'
gitlab_1      | /home/git/gitlab/vendor/bundle/ruby/2.3.0/gems/activesupport-4.2.8/lib/active_support/key_generator.rb:38:in `generate_key'
gitlab_1      | /home/git/gitlab/vendor/bundle/ruby/2.3.0/gems/railties-4.2.8/lib/rails/application.rb:206:in `message_verifier'
gitlab_1      | /home/git/gitlab/vendor/bundle/ruby/2.3.0/gems/globalid-0.3.7/lib/global_id/railtie.rb:25:in `block (2 levels) in <class:Railtie>'
gitlab_1      | /home/git/gitlab/vendor/bundle/ruby/2.3.0/gems/activesupport-4.2.8/lib/active_support/lazy_load_hooks.rb:36:in `execute_hook'
gitlab_1      | /home/git/gitlab/vendor/bundle/ruby/2.3.0/gems/activesupport-4.2.8/lib/active_support/lazy_load_hooks.rb:45:in `block in run_load_hooks'
gitlab_1      | /home/git/gitlab/vendor/bundle/ruby/2.3.0/gems/activesupport-4.2.8/lib/active_support/lazy_load_hooks.rb:44:in `each'
gitlab_1      | /home/git/gitlab/vendor/bundle/ruby/2.3.0/gems/activesupport-4.2.8/lib/active_support/lazy_load_hooks.rb:44:in `run_load_hooks'
gitlab_1      | /home/git/gitlab/vendor/bundle/ruby/2.3.0/gems/railties-4.2.8/lib/rails/application/finisher.rb:62:in `block in <module:Finisher>'
gitlab_1      | /home/git/gitlab/vendor/bundle/ruby/2.3.0/gems/railties-4.2.8/lib/rails/initializable.rb:30:in `instance_exec'
gitlab_1      | /home/git/gitlab/vendor/bundle/ruby/2.3.0/gems/railties-4.2.8/lib/rails/initializable.rb:30:in `run'
gitlab_1      | /home/git/gitlab/vendor/bundle/ruby/2.3.0/gems/railties-4.2.8/lib/rails/initializable.rb:55:in `block in run_initializers'
gitlab_1      | /home/git/gitlab/vendor/bundle/ruby/2.3.0/gems/railties-4.2.8/lib/rails/initializable.rb:54:in `run_initializers'
gitlab_1      | /home/git/gitlab/vendor/bundle/ruby/2.3.0/gems/railties-4.2.8/lib/rails/application.rb:352:in `initialize!'
gitlab_1      | /home/git/gitlab/config/environment.rb:5:in `<top (required)>'
gitlab_1      | /home/git/gitlab/vendor/bundle/ruby/2.3.0/gems/activesupport-4.2.8/lib/active_support/dependencies.rb:274:in `require'
gitlab_1      | /home/git/gitlab/vendor/bundle/ruby/2.3.0/gems/activesupport-4.2.8/lib/active_support/dependencies.rb:274:in `block in require'
gitlab_1      | /home/git/gitlab/vendor/bundle/ruby/2.3.0/gems/activesupport-4.2.8/lib/active_support/dependencies.rb:240:in `load_dependency'
gitlab_1      | /home/git/gitlab/vendor/bundle/ruby/2.3.0/gems/activesupport-4.2.8/lib/active_support/dependencies.rb:274:in `require'
gitlab_1      | /home/git/gitlab/vendor/bundle/ruby/2.3.0/gems/railties-4.2.8/lib/rails/application.rb:328:in `require_environment!'
gitlab_1      | /home/git/gitlab/vendor/bundle/ruby/2.3.0/gems/railties-4.2.8/lib/rails/application.rb:457:in `block in run_tasks_blocks'
gitlab_1      | Tasks: TOP => gitlab:setup => environment
gitlab_1      | (See full trace by running task with --trace)
dockergitlabbugreport_gitlab_1 exited with code 1

The values are strings in the context of docker-compose (courtesy of docker-compose.yml parsing I guess):

❯ docker-compose config | grep GITLAB_SECRETS
      GITLAB_SECRETS_DB_KEY_BASE: '123456789012345678901234567890'
      GITLAB_SECRETS_OTP_KEY_BASE: '123456789012345678901234567890'
      GITLAB_SECRETS_SECRET_KEY_BASE: '123456789012345678901234567890'

However, the values become numbers in config/secrets.yml:

❯ docker-compose exec gitlab cat config/secrets.yml
production:
  # db_key_base is used to encrypt for Variables. Ensure that you don't lose it.
  # If you change or lose this key you will be unable to access variables stored in database.
  # Make sure the secret is at least 30 characters and all random,
  # no regular words or you'll be exposed to dictionary attacks.
  db_key_base: 123456789012345678901234567890
  secret_key_base: 123456789012345678901234567890
  otp_key_base: 123456789012345678901234567890

development:
  db_key_base: development

test:
  db_key_base: test

In case it's needed:

❯ docker info
Containers: 8
 Running: 4
 Paused: 0
 Stopped: 4
Images: 4
Server Version: 17.04.0-ce
Storage Driver: aufs
 Root Dir: /var/lib/docker/aufs
 Backing Filesystem: extfs
 Dirs: 41
 Dirperm1 Supported: true
Logging Driver: json-file
Cgroup Driver: cgroupfs
Plugins:
 Volume: local
 Network: bridge host macvlan null overlay
Swarm: inactive
Runtimes: runc
Default Runtime: runc
Init Binary:
containerd version: 422e31ce907fd9c3833a38d7b8fdd023e5a76e73
runc version: 9c2d8d184e5da67c95d601382adf14862e4f2228
init version: 949e6fa
Security Options:
 apparmor
 seccomp
  Profile: default
Kernel Version: 4.4.0-72-generic
Operating System: Ubuntu 16.04.2 LTS
OSType: linux
Architecture: x86_64
CPUs: 4
Total Memory: 7.503GiB
Name: havet
ID: YWIW:5WW3:N7UX:WGBR:57PT:WFZZ:KMNJ:25UZ:USZ6:FQ6A:5M43:XVOY
Docker Root Dir: /var/lib/docker
Debug Mode (client): false
Debug Mode (server): false
Registry: https://index.docker.io/v1/
Experimental: false
Insecure Registries:
 127.0.0.0/8
Live Restore Enabled: false

WARNING: No swap limit support

Start with the GITLAB_SECRETS_* handling that generates config/secrets.yml, using the docker-compose.yml reproduction and the shown docker-compose config output. Check how numeric-looking environment values are serialized, then confirm the generated secrets remain strings and Rails initialization completes without the TypeError.