chang-compose.rb

#!/usr/bin/env ruby

require 'yaml'
require 'set'
require 'json'

def env(key)
  ENV.fetch key
end

def chang_service_network_alias(name)
  `/usr/bin/env bash ${CHANG_SET} -c "chang_service_network_alias #{name}"`.chomp
end

def chang_external_volume_name(name)
  `/usr/bin/env bash ${CHANG_SET} -c "chang_external_volume_name #{name}"`.chomp
end

def chang_error(msg)
  `chang_error #{msg}`
  exit 1
end

chang_compose_file = ARGV[0]
chang_compose = YAML.load(File.read chang_compose_file)

CHANG_SYNC_ENABLED = env("CHANG_SYNC_ENABLED") == "true"
CHANG_NETWORK = env("CHANG_NETWORK")
CHANG_TMP_PATH = env("CHANG_TMP_PATH")
CHANG_ENVIRONMENT = chang_compose.delete("environment") || []
DOCKER_COMPOSE_FILE = env("DOCKER_COMPOSE_FILE")

VOLUMES = Set.new
SERVICES = Hash.new

File.open(File.join(CHANG_TMP_PATH, "environment"), "w") do |env_file|
  CHANG_ENVIRONMENT.each do |line|
    env_file.puts("export #{line}")
  end
end

def expand_env_variables(str)
  `source #{CHANG_TMP_PATH}/environment && echo #{str}`.chomp
end

chang_compose.fetch("services").each do |name, service|
  service.fetch("volumes", []).map! do |volume|
    case volume
    when /^chang:(.*)/
      if CHANG_SYNC_ENABLED
        VOLUMES.add("chang")
        "#{volume.sub(/:nocopy$/, "")}:nocopy"
      else
        "../../:#{$1.sub(/:nocopy$/, "")}"
      end
    when Hash
      chang_error "Hash syntax in services volumes is not supported: #{volume.inspect}"
    when /([^:]+):(.+)/
      expanded_name = expand_env_variables $1
      VOLUMES.add(expanded_name)
      "#{expanded_name}:#{$2}"
    else
      chang_error "Unrecognized service volume syntax: #{volume.inspect}"
    end
  end
  service["networks"] ||= {}
  service["networks"].merge! \
    "chang" => {
      "aliases" => \
        service["networks"]
         .fetch("chang", {})
         .fetch("aliases", [])
         .push(chang_service_network_alias(name))
    }
  service["environment"] ||= []
  service["environment"] = (service.key?("extends") ? [] : CHANG_ENVIRONMENT) + service["environment"]
end

chang_compose["volumes"] ||= {}
chang_compose["volumes"]
VOLUMES.-(chang_compose["volumes"].keys).each do |volume|
  chang_compose["volumes"][volume] = {
    "name" => chang_external_volume_name(volume),
    "external" => true
  }
end

chang_compose["networks"] ||= {}
chang_compose["networks"]["chang"] = {
  "name" => CHANG_NETWORK,
  "external" => true
}

File.open(File.join(CHANG_TMP_PATH, "volumes"), "w") do |volumes_file|
  VOLUMES.each do |volume|
    volumes_file.puts(chang_external_volume_name(volume))
  end
end

File.open(File.join(CHANG_TMP_PATH, "proxy"), "w") do |proxy_file|
  if root = chang_compose.fetch("server", {})["root"]
    service, port = root.split(":")
    proxy_file.puts("$CHANG_NETWORK $CHANG_APP_NAME $CHANG_REV_PROXY_PORT #{service} #{port}")
  end
  if subdomains = chang_compose.fetch("server", {})["subdomains"]
    subdomains.each do |name, target|
      service, port = target.split(":")
      proxy_file.puts("$CHANG_NETWORK #{name}.$CHANG_APP_NAME $CHANG_REV_PROXY_PORT #{service} #{port}")
    end
  end
  if subdomains = chang_compose.fetch("server", {})["ports"]
    subdomains.each do |port, target|
      service, port = target.split(":")
      proxy_file.puts("$CHANG_NETWORK $CHANG_APP_NAME #{port} #{service} #{port}")
    end
  end
end

chang_compose.delete("environment")
chang_compose.delete("server")

File.open(DOCKER_COMPOSE_FILE, "w") do |docker_compose_file|
  docker_compose_file.write(chang_compose.to_yaml)
end