circle.yml

test:
  override:
    - bundle exec rspec spec

deployment:
  acceptance:
    branch: master
    commands:
      - ./script/heroku_deploy.sh <ACCEPTANCE_HEROKU_APP>:
          timeout: 300
  staging:
    branch: staging
    commands:
      - ./script/heroku_deploy.sh <STAGING_HEROKU_APP>:
          timeout: 300
  production:
    branch: production
    commands:
      - ./script/heroku_deploy.sh <PRODUCTION_HEROKU_APP>:
          timeout: 300

heroku_deploy.sh

#!/bin/sh -e
APP_NAME=$1

git remote add heroku [email protected]:$APP_NAME.git
git fetch heroku
MIGRATION_CHANGES=$(git diff HEAD heroku/master --name-only -- db | wc -l)
echo "$MIGRATION_CHANGES db changes."

PREV_WORKERS=$(heroku ps --app $APP_NAME | grep "^worker." | wc -l | tr -d ' ')

# migrations require downtime so enter maintenance mode
if test $MIGRATION_CHANGES -gt 0; then
  heroku maintenance:on --app $APP_NAME

  # Make sure workers are not running during a migration
  heroku scale worker=0 --app $APP_NAME
fi

# deploy code changes (and implicitly restart the app and any running workers)
git push heroku $CIRCLE_SHA1:refs/heads/master

# run database migrations if needed and restart background workers once finished
if test $MIGRATION_CHANGES -gt 0; then
  heroku run rake db:migrate db:seed --app $APP_NAME
  heroku scale worker=$PREV_WORKERS --app $APP_NAME
  heroku restart --app $APP_NAME
fi

heroku run rake cache:flush --app $APP_NAME
heroku maintenance:off --app $APP_NAME

naive_heroku_deploy.sh

#!/bin/sh -e
APP_NAME=$1

heroku maintenance:on --app $APP_NAME
git push heroku $CIRCLE_SHA1:refs/heads/master
heroku run rake db:migrate db:seed --app $APP_NAME
heroku restart --app $APP_NAME
heroku maintenance:off --app $APP_NAME

persistent_pipeline_heroku_deploy.sh

#!/bin/sh -e
APP_NAME=$1
PIPELINE_APP_NAME=$APP_NAME-slug
[email protected]:$APP_NAME.git
[email protected]:$PIPELINE_APP_NAME.git
WORKERS_COUNT=$(heroku ps --app $APP_NAME | grep "^worker." | wc -l | tr -d ' ')

# configure pipeline deploy https://devcenter.heroku.com/articles/labs-pipelines
heroku plugins:install git://github.com/heroku/heroku-pipeline.git
if test $(heroku apps | grep $PIPELINE_APP_NAME -c) -gt 0; then
  echo "Using existing pipeline $PIPELINE_APP_NAME"
  git remote add pipeline $HEROKU_PIPELINE_REMOTE
  DIFF_REMOTE=pipeline
else
  heroku apps:create $PIPELINE_APP_NAME --remote pipeline
  heroku labs:enable pipelines --app $PIPELINE_APP_NAME
  heroku pipeline:add $APP_NAME --app $PIPELINE_APP_NAME
  heroku pipeline --app $PIPELINE_APP_NAME

  git remote add heroku $HEROKU_APP_REMOTE
  DIFF_REMOTE=heroku
fi

# configure app and check for db changes
git fetch $DIFF_REMOTE
MIGRATION_CHANGES=$(git diff $CIRCLE_SHA1 $DIFF_REMOTE/master --name-only -- db | wc -l)
echo "$MIGRATION_CHANGES db changes since last deploy."

# use pipeline to prepare a slug to deploy
git push pipeline $CIRCLE_SHA1:refs/heads/master

DEPLOY_START=`date +%s`

# migrations require downtime so enter maintenance mode
if test $MIGRATION_CHANGES -gt 0; then
  heroku maintenance:on --app $APP_NAME

  # Make sure workers are not running during a migration
  heroku scale worker=0 --app $APP_NAME
fi

# Run our migrations in a subprocess so that failed db migrations
# don't immediately abort our deploy script.
(
  # promote the compiled slug
  heroku pipeline:promote --app $PIPELINE_APP_NAME

  # run database migrations if needed and restart background workers once finished
  if test $MIGRATION_CHANGES -gt 0; then
    heroku run rake db:migrate --app $APP_NAME
    heroku run rake db:seed --app $APP_NAME
    heroku restart --app $APP_NAME
  fi
)
MIGRATION_EXIT=$? # store the exit code

# Always scale our workers back up, regardless of whether the migration failed
if test $MIGRATION_CHANGES -gt 0; then
  heroku scale worker=$WORKERS_COUNT --app $APP_NAME
fi

# If the migration failed, now we can exit with that exit code
if test $MIGRATION_EXIT -ne 0; then
  exit $MIGRATION_EXIT
fi

heroku run rake cache:flush --app $APP_NAME
heroku maintenance:off --app $APP_NAME

DEPLOY_END=`date +%s`
ELAPSED=$(( $DEPLOY_END - $DEPLOY_START ))

echo "Deploy completed!"
if test $MIGRATION_CHANGES -gt 0; then
  echo "  $ELAPSED seconds in maintenance mode."
else
  echo "  $ELAPSED seconds, without maintenance mode."
fi

exit 0

pipeline_heroku_deploy.sh

#!/bin/sh -e
APP_NAME=$1
PIPELINE_APP_NAME=$APP_NAME-slug
[email protected]:$APP_NAME.git
[email protected]:$PIPELINE_APP_NAME.git
WORKERS_COUNT=$(heroku ps --app $APP_NAME | grep "^worker." | wc -l | tr -d ' ')

# configure pipeline deploy https://devcenter.heroku.com/articles/labs-pipelines
if test $(heroku apps | grep $PIPELINE_APP_NAME -c) -gt 0; then
  echo "Using existing pipeline $PIPELINE_APP_NAME"
  git remote add pipeline $HEROKU_PIPELINE_REMOTE
else
  heroku apps:create $PIPELINE_APP_NAME --remote pipeline
  heroku labs:enable pipelines --app $PIPELINE_APP_NAME
fi
heroku plugins:install git://github.com/heroku/heroku-pipeline.git
heroku pipeline:add $APP_NAME --app $PIPELINE_APP_NAME
heroku pipeline --app $PIPELINE_APP_NAME

# configure app and check for db changes
git remote add heroku $HEROKU_APP_REMOTE
git fetch heroku
MIGRATION_CHANGES=$(git diff $CIRCLE_SHA1 heroku/master --name-only -- db | wc -l)
echo "$MIGRATION_CHANGES db changes since last deploy."

# use pipeline to prepare a slug to deploy
git push pipeline $CIRCLE_SHA1:refs/heads/master

DEPLOY_START=`date +%s`

# migrations require downtime so enter maintenance mode
if test $MIGRATION_CHANGES -gt 0; then
  heroku maintenance:on --app $APP_NAME

  # Make sure workers are not running during a migration
  heroku scale worker=0 --app $APP_NAME
fi

# promote the compiled slug
heroku pipeline:promote --app $PIPELINE_APP_NAME

# run database migrations if needed and restart background workers once finished
if test $MIGRATION_CHANGES -gt 0; then
  heroku run rake db:migrate db:seed --app $APP_NAME
  heroku restart --app $APP_NAME
  heroku scale worker=$PREV_WORKERS --app $APP_NAME
fi

heroku run rake cache:flush --app $APP_NAME
heroku maintenance:off --app $APP_NAME

DEPLOY_END=`date +%s`
ELAPSED=$(( $DEPLOY_END - $DEPLOY_START ))

# HACK!
# Pipelines do not update the git repository on downstream apps.
#
# In order to be able to diff for db changes against the app overwrite the pipeline
# deploy with a git push of the same commit.
#
# Since this we already ran any required migrations this can always be a
# zero-downtime deploy we don't need to enable maintenance mode and are no longer
# sensetive to long asset precompilation times or other delays.
#
# We could remove this if we want to maintain a persistent pipeline app and always
# diff against that app to determine if db changes exist. Alternately we might
# be able to parse `heroku pipeline:diff` output for commit hashes and check for
# db changes in each commit.
git push heroku $CIRCLE_SHA1:refs/heads/master -f

# remove the pipeline app
heroku apps:destroy --app $PIPELINE_APP_NAME --confirm $PIPELINE_APP_NAME

echo "Deploy completed!"
if test $MIGRATION_CHANGES -gt 0; then
  echo "  $ELAPSED seconds in maintenance mode."
else
  echo "  $ELAPSED seconds, without maintenance mode."
fi

precompile_heroku_deploy.sh

#!/bin/sh -e
APP_NAME=$1

git remote add heroku [email protected]:$APP_NAME.git
git fetch heroku
MIGRATION_CHANGES=$(git diff HEAD heroku/master --name-only -- db | wc -l)
echo "$MIGRATION_CHANGES db changes since last deploy."

rake assets:precompile
git config user.name "CircleCi"
git config user.email "[email protected]"
git add public/assets
git commit -m "Precompile assets"

PREV_WORKERS=$(heroku ps --app $APP_NAME | grep "^worker." | wc -l | tr -d ' ')

# migrations require downtime so enter maintenance mode
if test $MIGRATION_CHANGES -gt 0; then
  heroku maintenance:on --app $APP_NAME

  # Make sure workers are not running during a migration
  heroku scale worker=0 --app $APP_NAME
fi

# deploy code changes (and implicitly restart the app and any running workers)
git push heroku HEAD:refs/heads/master -f

# run database migrations if needed and restart background workers once finished
if test $MIGRATION_CHANGES -gt 0; then
  heroku run rake db:migrate db:seed --app $APP_NAME
  heroku restart --app $APP_NAME
  heroku scale worker=$PREV_WORKERS --app $APP_NAME
fi

heroku run rake cache:flush --app $APP_NAME
heroku maintenance:off --app $APP_NAME