jenkins_tag.rb

require 'json'
require 'net/http'
require 'hako/script'

module Hako
  module Scripts
    class JenkinsTag < Script
      JENKINS_BASE = 'https://jenkins.example.com'
      TARGET_TAG = 'jenkins'

      def configure(options)
        super
        @job_name = options.fetch('job', "docker-#{@app.id}") # default naming convention
      end

      def deploy_starting(containers)
        app = containers.fetch('app')
        if app.definition['tag'] == TARGET_TAG
          rewrite_tag(app)
        end
      end

      alias_method :oneshot_starting, :deploy_starting

      private

      def rewrite_tag(container)
        tag = fetch_revision(@job_name)
        container.definition['tag'] = tag
        Hako.logger.info("Rewrite tag to #{container.image_tag}")
      end

      def fetch_revision(job_name)
        body = Net::HTTP.get(URI.parse("#{JENKINS_BASE}/job/#{@job_name}/lastSuccessfulBuild/git/api/json"))
        git_data = JSON.parse(body)
        git_data['lastBuiltRevision']['SHA1']
      rescue => e
        Hako.logger.error("Unable to fetch revision from #{JENKINS_BASE}/job/#{@job_name}/")
        raise e
      end
    end
  end
end