Guides
Rails: Webpack compile once for parallel tests
When we use gem parallel_tests our application in test environment used, for example, 8 parallel processes. But webpacker compiling the same files at the same time in each process.
This is bad and can lead to unexpected errors.
Also when assets did not change, we do not want to spend time compiling them.
For solving this problem we can use next configuration module.
Place the following into features/support/webpacker.rb.
# frozen_string_literal: true
module WebpackerTestSupport
TS_FILE = Rails.root.join('tmp', "webpacker-#{Rails.env}-timestamp")
def self.compile_once
return unless timestamp_outdated?
if ENV['TEST_ENV_NUMBER'].to_i < 1
public_output_path = Webpacker.config.public_output_path
FileUtils.rm_r(public_output_path) if File.exist?(public_output_path)
puts "Webpack is removed from output directory #{public_output_path}"
puts 'Compiling, please wait'
Webpacker.compile
File.open(TS_FILE, 'w') { |f| f.write(Time.now.utc.to_i) }
sleep(1)
else
loop do
break unless timestamp_outdated?
sleep 0.1
end
end
end
def self.timestamp_outdated?
return true unless File.exist?(Webpacker.config.public_output_path)
return true unless File.exist?(TS_FILE)
current = current_bundle_timestamp(TS_FILE)
return true unless current
expected = Dir[Webpacker.config.source_path.join('**', '*')].map do |f|
File.mtime(f).utc.to_i
end.max
current < expected
end
def self.current_bundle_timestamp(file)
File.read(file).to_i
rescue StandardError
nil
end
end
WebpackerTestSupport.compile_once