trigger-dependent-build.sh

#!/bin/bash

# This script lives in each of the upstream repos. Add this to .travis.yml to
# run after each successful build (assuming that the script is in the root of
# the repo):
#   after_success:
#     - ./trigger-dependent-build
#
# There are three variables to set - `$auth_token`, `$endpoint`, and
# `$repo_id` - each is described below.
#

# An authorization token generated by running:
#   gem install travis
#   travis login
#   travis token
#
auth_token=$TRAVIS_TOKEN

# The Travis API endpoint. .com and .org are the commercial and free versions,
# respectively; enterprise users will have their own hostname.
#
endpoint=https://api.travis-ci.org

# The ID of the tests repo. To find the ID of a repo from its slug `$slug`, run:
#   curl -H 'Authorization: token $auth_token' https://api.travis-ci.com/repos/$slug
#
repo_id=6629241

# Only run for master builds. Pull request builds have the branch set to master,
# so ignore those too.
#
if [ "${TRAVIS_BRANCH}" != "master" ] || [ "${TRAVIS_PULL_REQUEST}" != "false" ]; then
  exit 0
fi

# Make an API request using the auth token set above. First argument is the path
# of the API method, all later arguments are passed to curl directly.
#
function travis-api {
  curl -s $endpoint$1 \
       -H "Authorization: token $auth_token" \
       -H 'Content-Type: application/json' \
       "${@:2}"
}

# Create a new environment variable for the repo and return its ID. First
# argument is the environment variable name, and the second is the value.
#
function env-var {
  travis-api /settings/env_vars?repository_id=$repo_id \
             -d "{\"env_var\":{\"name\":\"$1\",\"value\":\"$2\",\"public\":false}}" |
    sed 's/{"env_var":{"id":"\([^"]*\)",.*/\1/'
}

# Get the build ID of the last master build.
#
last_master_build_id=`travis-api /repos/$repo_id/branches/master |
                      sed 's/{"branch":{"id":\([0-9]*\),.*/\1/'`

# Set the three environment variables needed, and capture their IDs so that they
# can be removed later.
#
env_var_ids=(`env-var DEPENDENT_BUILD true`
             `env-var TRIGGER_COMMIT $TRAVIS_COMMIT`
             `env-var TRIGGER_REPO $TRAVIS_REPO_SLUG`
             `env-var GORM_VERSION "5.0.3.BUILD-SNAPSHOT"`)

# Restart the last master build.
#
travis-api /builds/$last_master_build_id/restart -X POST

# Wait for the build to start using the new environment variables.
#
until travis-api /builds/$last_master_build_id | grep '"state":"started"'; do
  sleep 5
done

# Get the build ID of the last 3.1.x build.
#
last_threeone_build_id=`travis-api /repos/$repo_id/branches/3.1.x |
                      sed 's/{"branch":{"id":\([0-9]*\),.*/\1/'`

# Restart the last 3.1.x build.
#
travis-api /builds/$last_threeone_build_id/restart -X POST

# Wait for the build to start using the new environment variables.
#
until travis-api /builds/$last_threeone_build_id | grep '"state":"started"'; do
  sleep 5
done

# Remove all of the environment variables set above. This does mean that if this
# script is terminated for whatever reason, these will need to be cleaned up
# manually. We can do this either through the API, or by going to Settings ->
# Environment Variables in the Travis web interface.
#
for env_var_id in "${env_var_ids[@]}"; do
  travis-api /settings/env_vars/$env_var_id?repository_id=$repo_id -X DELETE
done