Module: Retest::Watcher::Watchexec

Defined in:
lib/retest/watcher.rb

Class Method Summary collapse

Class Method Details

.installed? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/retest/watcher.rb', line 76

def self.installed?
  system "watchexec --version > /dev/null 2>&1"
end

.watch(dir:, extensions:, polling: false) ⇒ Object 



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# File 'lib/retest/watcher.rb', line 80

def self.watch(dir:, extensions:, polling: false)
  command = "watchexec --exts #{extensions.join(',')} -w #{dir} --emit-events-to stdio --no-meta --only-emit-events"

  watch_rd, watch_wr = IO.pipe
  # Process needs its own process group otherwise the process gets killed on INT signal
  # We need the process to still run when trying to stop the current test run
  # Maybe there is another way to prevent killing these but for now a new process groups works
  # Process group created with: pgroup: true
  pid = Process.spawn(command, out: watch_wr, pgroup: true)

  thread = Thread.new do
    files = VersionControl.files(extensions: extensions).zip([]).to_h

    loop do
      ready = IO.select([watch_rd])
      readable_connections = ready[0]
      readable_connections.each do |conn|
        data = conn.readpartial(4096)
        # Watchexec is not great at figuring out whether a file has been deleted and comes as an update.
        # This is why we're not looking at the action like we do with Listen.
        change = /^(?:create|remove|rename|modify):(?<path>.*)/.match(data.strip)

        next unless change

        path = Pathname(change[:path]).relative_path_from(Dir.pwd).to_s
        file_exist = File.exist?(path)
        file_cached = files.key?(path)

        modified, added, removed = result = [[], [], []]
        if file_exist && file_cached
          modified << path
        elsif file_exist && !file_cached
          added << path
          files[path] = nil
        elsif !file_exist && file_cached
          removed << path
          files.delete(path)
        end

        yield result
      end
    end
  end

  at_exit do
    thread.exit
    Process.kill("TERM", pid) if pid
    watch_rd.close
    watch_wr.close
  end
end