travis-api/lib/travis/model/repository/status_image.rb

class Repository
  class StatusImage
    RESULTS = {
      passed:  :passing,
      failed:  :failing,
      errored: :error,
      canceled: :canceled
    }

    attr_reader :repo, :branch

    def initialize(repo, branch = nil)
      @repo = repo
      @branch = branch
    end

    def result
      last_state ? RESULTS[last_state] : :unknown
    end

    private

      def cache_enabled?
        defined?(@cache_enabled) ? @cache_enabled : @cache_enabled = Travis::Features.feature_active?(:states_cache)
      end

      def last_state
        @last_state ||= (state_from_cache || state_from_database)
      end

      def state_from_cache
        return unless repo
        return unless cache_enabled?

        cache.fetch_state(repo.id, branch).tap do |result|
          if result
            Metriks.meter('status-image.cache-hit').mark
          else
            Metriks.meter('status-image.cache-miss').mark
          end
        end
      rescue Travis::StatesCache::CacheError => e
        Travis.logger.error(e.message)
        return nil
      end

      def state_from_database
        return unless repo

        build = repo.last_completed_build(branch)
        if build
          cache.write(repo.id, build.branch, build) if cache_enabled?
          build.state.to_sym
        end
      end

      def cache
        Travis.states_cache
      end
  end
end