WARNING: This script creates an infinity loop in your CI, make sure to have a timeout.

Initially I though of using wait-for-it.sh but to add a new script (aka, dependency) for this whole thing, besides it does not work as I want.

I was expecting for the script to go on in one infinity loop until the connection is healthy.

For MySQL:


while ! mysql -h db -D app_test -e "select 1"
  echo "waiting for MySQL"
  sleep 5

For PostgreSQL:


export PGPASSWORD=postgres

while ! echo "select 1" | psql -U postgres -h db postgres
  echo "waiting for PostgreSQL"
  sleep 2

I put this script right before I need to use the database, for example:

      - run: docker-compose up -d db
      - run: docker-compose run --rm -e RAILS_ENV=test app bundle install --path=vendor/bundle --jobs=4 --retry=3
      - run: docker-compose run db /app/.github/wait-for-db.sh
      - run: docker-compose run --rm -e RAILS_ENV=test app bundle exec rake db:migrate

This is what I got in my Github Action:

Example CI

P. S.: Don't forget to make your script executable using chmod +x.