Merge pull request #43 from basecamp/puma-plugin

Add a Puma plugin for Solid Queue

lib/puma/plugin/solid_queue.rb

@@ -0,0 +1,63 @@
+require "puma/plugin"
+
+Puma::Plugin.create do
+ attr_reader :puma_pid, :solid_queue_pid, :log_writer
+
+ def start(launcher)
+ @log_writer = launcher.log_writer
+ @puma_pid = $$
+ @solid_queue_pid = fork do
+ Thread.new { monitor_puma }
+ SolidQueue::Supervisor.start(mode: :all)
+ end
+
+ launcher.events.on_stopped { stop_solid_queue }
+
+ in_background do
+ monitor_solid_queue
+ end
+ end
+
+ private
+ def stop_solid_queue
+ Process.waitpid(solid_queue_pid, Process::WNOHANG)
+ log "Stopping Solid Queue..."
+ Process.kill(:INT, solid_queue_pid) if solid_queue_pid
+ Process.wait(solid_queue_pid)
+ rescue Errno::ECHILD, Errno::ESRCH
+ end
+
+ def monitor_puma
+ monitor(:puma_dead?, "Detected Puma has gone away, stopping Solid Queue...")
+ end
+
+ def monitor_solid_queue
+ monitor(:solid_queue_dead?, "Detected Solid Queue has gone away, stopping Puma...")
+ end
+
+ def monitor(process_dead, message)
+ loop do
+ if send(process_dead)
+ log message
+ Process.kill(:INT, $$)
+ break
+ end
+ sleep 2
+ end
+ end
+
+ def solid_queue_dead?
+ Process.waitpid(solid_queue_pid, Process::WNOHANG)
+ false
+ rescue Errno::ECHILD, Errno::ESRCH
+ true
+ end
+
+ def puma_dead?
+ Process.ppid != puma_pid
+ end
+
+ def log(...)
+ log_writer.log(...)
+ end
+end