Building single/partial steps from cloudbuild.yaml

build.rb

remote = ARGV.delete("--remote")
id = ARGV.pop

abort "Usage: ruby build.rb <id|all> [--remote]" unless ARGV.empty?

unless system('which container-builder-local')
  abort "Run: gcloud components install container-builder-local"
end

def dependencies(steps, id)
  step = steps.detect { |s| s.fetch("id") == id }
  [id] + (step["waitFor"] || []).flat_map { |w| dependencies(steps, w) }
end

# make sure to use all variables to avoid:
# "invalid build: key in the substitution data is not matched in the template"
def echo_step
  {
    "id" => "echo",
    "name" => "gcr.io/cloud-builders/wget",
    "entrypoint" => "echo",
    "args" => ["_IMAGE_DIR is $_IMAGE_DIR"]
  }
end

require 'yaml'
config = YAML.load_file("cloudbuild.yaml")
config.delete("images")

unless id == "all"
  steps = config.fetch("steps")
  keep = dependencies(steps, id)
  steps.select! { |s| keep.include? s.fetch("id") }
  steps.unshift(echo_step)
  puts "Running steps #{steps.map { |s| s.fetch("id")}.join(", ")}"
else
  puts "Running all steps"
end

require 'tempfile'
Tempfile.open("docker-images-base-test") do |f|
  f.write config.to_yaml
  f.close
  command = if remote
    "gcloud container builds submit --config=#{f.path} --substitutions=_IMAGE_DIR=tmp ."
  else
    "container-builder-local --config=#{f.path} --dryrun=false --substitutions=_IMAGE_DIR=tmp ."
  end
  puts command
  system(command)
  exit $?.exitstatus
end