Build Checkpoint for Render

build-checkpoint

#!/usr/bin/env ruby

require 'bundler/inline'
require 'optparse'
require 'timeout'

gemfile do
  source 'https://rubygems.org'
  gem 'redis'
end

class BuildCheckpoint
  TIMEOUT = 300
  POLLING = 2

  def initialize
    option_parser.parse!
    @build_count = ARGV.pop || 1
    @environment = ENV['RAILS_ENV'] or fail 'RAILS_ENV must be set'
    @commit = (ENV['RENDER_GIT_COMMIT'] or fail 'RENDER_GIT_COMMIT must be set')[1, 8]
    @redis = Redis.new(url: (ENV['BUILD_REDIS_URL'] or fail 'BUILD_REDIS_URL must be set'))
    @build_id = ['build-checkpoint', @namespace, @environment, @commit].compact.join('-')
    STDOUT.sync = true
  end

  def wait
    puts "⏳ waiting for other builds to reach #{@build_id}"
    @redis.set(@build_id, '0', nx: true, ex: TIMEOUT)
    Timeout::timeout(TIMEOUT) do
      @redis.incr(@build_id)
      loop do
        count = @redis.get(@build_id)
        fail Timeout::Error if count.nil?
        break if count >= @build_count
        sleep POLLING
      end
    end
    sleep POLLING + 2
    @redis.del(@build_id)
    puts "🎉 all #{@build_count} builds have reached the checkpoint"
  rescue Timeout::Error
    puts "💣 timeout elapsed - some builds may have failed"
    exit 1
  end

  private

  def option_parser
    OptionParser.new do |o|
      o.banner = <<~END
        Waits until NUMBER of builds have reached this checkpoint or the timeout is reached
        Usage: build-checkpoint NUMBER
      END
      o.on('-n', '--namespace STRING', String, 'optional namespace to further isolate this checkpoint (default: none)') { |v| @namespace = v }
    end
  end
end

begin
  BuildCheckpoint.new.wait
rescue => exception
  puts "#{File.basename($0)}: #{exception.message}"
  exit 1
end

In the Render Feedback comment:

For this to work, you have to set BUILD_RENDER_URL to a Render service (internal URL is okay).

Do you mean BUILD_REDIS_URL?

Also, I'm curious what the sleep is for on line 38? To make sure all waiting builds see the updated value before deleting?

@digerata Yeah, BUILD_REDIS_URL it is. Without the extra sleep, my builds (which vary a lot in build speed) sometimes matched to pass the checkpoint but then caused trouble down the lane. Your mileage may vary, you might just try whether it's working without for you.