This demonstrates the problem with trying to run rake db:migrate as part of the slug compilation process when the an app is first deployed to Heroku.
# Create new Rails app
$ rails new --database=postgresql testing-migrations
$ git init
$ git add .
$ git commit -m 'Add empty Rails project'
# Use scaffolding to create a database migration
$ rails g scaffold person name:string
$ git add .
$ git commit -m 'Add person scaffolding'
# Create Heroku app
$ heroku apps:create
Creating app... done, ⬢ calm-ridge-11009
https://calm-ridge-11009.herokuapp.com/ | https://git.heroku.com/calm-ridge-11009.git
# Set Heroku app to use Ruby buildpack
$ heroku buildpacks:set heroku/ruby
Buildpack set. Next release on calm-ridge-11009 will use heroku/ruby.
Run git push heroku master to create a new release using this buildpack.
# Add Rake buildpack to Heroku app
$ heroku buildpacks:add https://github.com/gunpowderlabs/buildpack-ruby-rake-deploy-tasks
Buildpack added. Next release on calm-ridge-11009 will use:
1. heroku/ruby
2. https://github.com/gunpowderlabs/buildpack-ruby-rake-deploy-tasks
Run git push heroku master to create a new release using these buildpacks.
# Configure Rake buildpack to run `rake db:migrate`
$ heroku config:set DEPLOY_TASKS=db:migrate
Setting DEPLOY_TASKS and restarting ⬢ calm-ridge-11009... done, v3
DEPLOY_TASKS: db:migrate
# Deploy the app
# Observe that it fails because the database doesn't appear to be available
$ git push heroku master
Counting objects: 101, done.
Delta compression using up to 4 threads.
Compressing objects: 100% (87/87), done.
Writing objects: 100% (101/101), 22.63 KiB | 0 bytes/s, done.
Total 101 (delta 8), reused 0 (delta 0)
remote: Compressing source files... done.
remote: Building source:
remote:
remote: -----> Ruby app detected
remote: -----> Compiling Ruby/Rails
remote: -----> Using Ruby version: ruby-2.2.4
remote: -----> Installing dependencies using bundler 1.11.2
remote: Running: bundle install --without development:test --path vendor/bundle --binstubs vendor/bundle/bin -j4 --deployment
remote: Fetching gem metadata from https://rubygems.org/...........
remote: Fetching version metadata from https://rubygems.org/...
remote: Fetching dependency metadata from https://rubygems.org/..
remote: Installing i18n 0.7.0
remote: Installing json 1.8.3 with native extensions
remote: Installing rake 11.3.0
remote: Installing minitest 5.9.0
remote: Installing thread_safe 0.3.5
remote: Installing builder 3.2.2
remote: Installing erubis 2.7.0
remote: Installing mini_portile2 2.1.0
remote: Installing pkg-config 1.1.7
remote: Installing rack 1.6.4
remote: Installing mime-types-data 3.2016.0521
remote: Installing arel 6.0.3
remote: Installing coffee-script-source 1.10.0
remote: Installing execjs 2.7.0
remote: Installing thor 0.19.1
remote: Installing concurrent-ruby 1.0.2
remote: Using bundler 1.11.2
remote: Installing multi_json 1.12.1
remote: Installing pg 0.18.4 with native extensions
remote: Installing sass 3.4.22
remote: Installing tilt 2.0.5
remote: Installing turbolinks-source 5.0.0
remote: Installing tzinfo 1.2.2
remote: Installing rdoc 4.2.2
remote: Installing nokogiri 1.6.8 with native extensions
remote: Installing rack-test 0.6.3
remote: Installing mime-types 3.1
remote: Installing coffee-script 2.4.1
remote: Installing uglifier 3.0.2
remote: Installing sprockets 3.7.0
remote: Installing turbolinks 5.0.1
remote: Installing activesupport 4.2.7.1
remote: Installing sdoc 0.4.1
remote: Installing mail 2.6.4
remote: Installing rails-deprecated_sanitizer 1.0.3
remote: Installing globalid 0.3.7
remote: Installing activemodel 4.2.7.1
remote: Installing jbuilder 2.6.0
remote: Installing activejob 4.2.7.1
remote: Installing activerecord 4.2.7.1
remote: Installing rails-dom-testing 1.0.7
remote: Installing loofah 2.0.3
remote: Installing rails-html-sanitizer 1.0.3
remote: Installing actionview 4.2.7.1
remote: Installing actionpack 4.2.7.1
remote: Installing railties 4.2.7.1
remote: Installing actionmailer 4.2.7.1
remote: Installing sprockets-rails 3.2.0
remote: Installing coffee-rails 4.1.1
remote: Installing jquery-rails 4.2.1
remote: Installing rails 4.2.7.1
remote: Installing sass-rails 5.0.6
remote: Bundle complete! 12 Gemfile dependencies, 52 gems now installed.
remote: Gems in the groups development and test were not installed.
remote: Bundled gems are installed into ./vendor/bundle.
remote: Post-install message from rdoc:
remote: Depending on your version of ruby, you may need to install ruby rdoc/ri data:
remote: <= 1.8.6 : unsupported
remote: = 1.8.7 : gem install rdoc-data; rdoc-data --install
remote: = 1.9.1 : gem install rdoc-data; rdoc-data --install
remote: >= 1.9.2 : nothing to do! Yay!
remote: Bundle completed (27.80s)
remote: Cleaning up the bundler cache.
remote: -----> Preparing app for Rails asset pipeline
remote: Running: rake assets:precompile
remote: I, [2016-09-20T19:46:28.469317 #903] INFO -- : Writing /tmp/build_153d6064cc62d6c97ec023b5b72c86c8/public/assets/application-32aca96fccef5b517f233b349393ff0335e17dd66d613cfc701f61bf0d230635.js
remote: I, [2016-09-20T19:46:28.469822 #903] INFO -- : Writing /tmp/build_153d6064cc62d6c97ec023b5b72c86c8/public/assets/application-32aca96fccef5b517f233b349393ff0335e17dd66d613cfc701f61bf0d230635.js.gz
remote: I, [2016-09-20T19:46:28.499662 #903] INFO -- : Writing /tmp/build_153d6064cc62d6c97ec023b5b72c86c8/public/assets/application-0723cb9a2dd5a514d954f70e0fe0b89f6f9f1ae3a375c182f43b5f2b57e9c869.css
remote: I, [2016-09-20T19:46:28.499814 #903] INFO -- : Writing /tmp/build_153d6064cc62d6c97ec023b5b72c86c8/public/assets/application-0723cb9a2dd5a514d954f70e0fe0b89f6f9f1ae3a375c182f43b5f2b57e9c869.css.gz
remote: Asset precompilation completed (3.85s)
remote: Cleaning assets
remote: Running: rake assets:clean
remote:
remote: ###### WARNING:
remote: Include 'rails_12factor' gem to enable all platform features
remote: See https://devcenter.heroku.com/articles/rails-integration-gems for more information.
remote:
remote: ###### WARNING:
remote: You have not declared a Ruby version in your Gemfile.
remote: To set your Ruby version add this line to your Gemfile:
remote: ruby '2.2.4'
remote: # See https://devcenter.heroku.com/articles/ruby-versions for more information.
remote:
remote: ###### WARNING:
remote: No Procfile detected, using the default web server.
remote: We recommend explicitly declaring how to boot your server process via a Procfile.
remote: https://devcenter.heroku.com/articles/ruby-default-web-server
remote:
remote: -----> Rake app detected
remote: rake aborted!
remote: PG::ConnectionBad: could not connect to server: No such file or directory
remote: Is the server running locally and accepting
remote: connections on Unix domain socket "/var/run/postgresql/.s.PGSQL.5432"?
remote: /tmp/build_153d6064cc62d6c97ec023b5b72c86c8/vendor/bundle/ruby/2.2.0/gems/activerecord-4.2.7.1/lib/active_record/connection_adapters/postgresql_adapter.rb:651:in `initialize'
remote: /tmp/build_153d6064cc62d6c97ec023b5b72c86c8/vendor/bundle/ruby/2.2.0/gems/activerecord-4.2.7.1/lib/active_record/connection_adapters/postgresql_adapter.rb:651:in `new'
remote: /tmp/build_153d6064cc62d6c97ec023b5b72c86c8/vendor/bundle/ruby/2.2.0/gems/activerecord-4.2.7.1/lib/active_record/connection_adapters/postgresql_adapter.rb:651:in `connect'
remote: /tmp/build_153d6064cc62d6c97ec023b5b72c86c8/vendor/bundle/ruby/2.2.0/gems/activerecord-4.2.7.1/lib/active_record/connection_adapters/postgresql_adapter.rb:242:in `initialize'
remote: /tmp/build_153d6064cc62d6c97ec023b5b72c86c8/vendor/bundle/ruby/2.2.0/gems/activerecord-4.2.7.1/lib/active_record/connection_adapters/postgresql_adapter.rb:44:in `new'
remote: /tmp/build_153d6064cc62d6c97ec023b5b72c86c8/vendor/bundle/ruby/2.2.0/gems/activerecord-4.2.7.1/lib/active_record/connection_adapters/postgresql_adapter.rb:44:in `postgresql_connection'
remote: /tmp/build_153d6064cc62d6c97ec023b5b72c86c8/vendor/bundle/ruby/2.2.0/gems/activerecord-4.2.7.1/lib/active_record/connection_adapters/abstract/connection_pool.rb:438:in `new_connection'
remote: /tmp/build_153d6064cc62d6c97ec023b5b72c86c8/vendor/bundle/ruby/2.2.0/gems/activerecord-4.2.7.1/lib/active_record/connection_adapters/abstract/connection_pool.rb:448:in `checkout_new_connection'
remote: /tmp/build_153d6064cc62d6c97ec023b5b72c86c8/vendor/bundle/ruby/2.2.0/gems/activerecord-4.2.7.1/lib/active_record/connection_adapters/abstract/connection_pool.rb:422:in `acquire_connection'
remote: /tmp/build_153d6064cc62d6c97ec023b5b72c86c8/vendor/bundle/ruby/2.2.0/gems/activerecord-4.2.7.1/lib/active_record/connection_adapters/abstract/connection_pool.rb:349:in `block in checkout'
remote: /tmp/build_153d6064cc62d6c97ec023b5b72c86c8/vendor/bundle/ruby/2.2.0/gems/activerecord-4.2.7.1/lib/active_record/connection_adapters/abstract/connection_pool.rb:348:in `checkout'
remote: /tmp/build_153d6064cc62d6c97ec023b5b72c86c8/vendor/bundle/ruby/2.2.0/gems/activerecord-4.2.7.1/lib/active_record/connection_adapters/abstract/connection_pool.rb:263:in `block in connection'
remote: /tmp/build_153d6064cc62d6c97ec023b5b72c86c8/vendor/bundle/ruby/2.2.0/gems/activerecord-4.2.7.1/lib/active_record/connection_adapters/abstract/connection_pool.rb:262:in `connection'
remote: /tmp/build_153d6064cc62d6c97ec023b5b72c86c8/vendor/bundle/ruby/2.2.0/gems/activerecord-4.2.7.1/lib/active_record/connection_adapters/abstract/connection_pool.rb:571:in `retrieve_connection'
remote: /tmp/build_153d6064cc62d6c97ec023b5b72c86c8/vendor/bundle/ruby/2.2.0/gems/activerecord-4.2.7.1/lib/active_record/connection_handling.rb:113:in `retrieve_connection'
remote: /tmp/build_153d6064cc62d6c97ec023b5b72c86c8/vendor/bundle/ruby/2.2.0/gems/activerecord-4.2.7.1/lib/active_record/connection_handling.rb:87:in `connection'
remote: /tmp/build_153d6064cc62d6c97ec023b5b72c86c8/vendor/bundle/ruby/2.2.0/gems/activerecord-4.2.7.1/lib/active_record/migration.rb:916:in `initialize'
remote: /tmp/build_153d6064cc62d6c97ec023b5b72c86c8/vendor/bundle/ruby/2.2.0/gems/activerecord-4.2.7.1/lib/active_record/migration.rb:823:in `new'
remote: /tmp/build_153d6064cc62d6c97ec023b5b72c86c8/vendor/bundle/ruby/2.2.0/gems/activerecord-4.2.7.1/lib/active_record/migration.rb:823:in `up'
remote: /tmp/build_153d6064cc62d6c97ec023b5b72c86c8/vendor/bundle/ruby/2.2.0/gems/activerecord-4.2.7.1/lib/active_record/migration.rb:801:in `migrate'
remote: /tmp/build_153d6064cc62d6c97ec023b5b72c86c8/vendor/bundle/ruby/2.2.0/gems/activerecord-4.2.7.1/lib/active_record/tasks/database_tasks.rb:137:in `migrate'
remote: /tmp/build_153d6064cc62d6c97ec023b5b72c86c8/vendor/bundle/ruby/2.2.0/gems/activerecord-4.2.7.1/lib/active_record/railties/databases.rake:44:in `block (2 levels) in <top (required)>'
remote: /tmp/build_153d6064cc62d6c97ec023b5b72c86c8/vendor/bundle/ruby/2.2.0/gems/rake-11.3.0/exe/rake:27:in `<top (required)>'
remote: Tasks: TOP => db:migrate
remote: (See full trace by running task with --trace)
remote: ! Push rejected, failed to compile Rake app.
remote:
remote: ! Push failed
remote: Verifying deploy...
remote:
remote: ! Push rejected to calm-ridge-11009.
remote:
To https://git.heroku.com/calm-ridge-11009.git
! [remote rejected] master -> master (pre-receive hook declined)
error: failed to push some refs to 'https://git.heroku.com/calm-ridge-11009.git'