Rainbows! Rack HTTP server user/dev discussion
 help / Atom feed
From: Eric Wong <e@80x24.org>
To: rainbows-public@bogomips.org
Cc: alex0375@gmail.com
Subject: [PATCH 2/2] eventmachine: wait for deferred actions to finish
Date: Mon, 9 Jan 2017 19:45:45 +0000
Message-ID: <20170109194545.GB16691@starla> (raw)
In-Reply-To: <20170109194337.GA16111@starla>

Since EventMachine 1.0.0 in 2012, the EM.defers_finish? API
exists to check for the existence of deferred actions.
Support it if it exists in the running version of EM and
update the note in our SIGNALS document.

Thanks to <alex0375@gmail.com> on the mailing list for bringing
this up:
https://bogomips.org/rainbows-public/CAKwvcL-VH3we4qA1pkNAstTmWvqNA=Rir2N_YiWztV_qbaLQvA@mail.gmail.com/
---
 SIGNALS                       |  6 +++---
 lib/rainbows/event_machine.rb | 10 +++++++++-
 t/app_deferred.ru             |  8 +++++++-
 t/t0700-app-deferred.sh       | 18 +++++++++++++++---
 4 files changed, 34 insertions(+), 8 deletions(-)

diff --git a/SIGNALS b/SIGNALS
index e53c3e4..fa95a1c 100644
--- a/SIGNALS
+++ b/SIGNALS
@@ -24,9 +24,9 @@ between \Rainbows!, unicorn and nginx.
 * INT/TERM - quick shutdown, kills all workers immediately
 
 * QUIT - graceful shutdown, waits for workers to finish their
-  current request before finishing.  This currently does not
-  wait for requests deferred to a separate thread when using
-  EventMachine (when app.deferred?(env) => true)
+  current request before finishing.  Since Rainbows 5.1.0 (Jan 2017),
+  this waits requests deferred to a separate thread with
+  EventMachine (app.deferred?(env) => true).
 
 * USR1 - reopen all logs owned by the master and all workers
   See Unicorn::Util.reopen_logs for what is considered a log.
diff --git a/lib/rainbows/event_machine.rb b/lib/rainbows/event_machine.rb
index b326e26..896fdac 100644
--- a/lib/rainbows/event_machine.rb
+++ b/lib/rainbows/event_machine.rb
@@ -65,6 +65,11 @@ def em_client_class
     end
   end
 
+  def defers_finished?
+    # EventMachine 1.0.0+ has defers_finished?
+    EM.respond_to?(:defers_finished?) ? EM.defers_finished? : true
+  end
+
   # runs inside each forked worker, this sits around and waits
   # for connections and doesn't die until the parent dies (or is
   # given a INT, QUIT, or TERM signal)
@@ -101,7 +106,10 @@ def worker_loop(worker) # :nodoc:
         end
       end
       EM.add_periodic_timer(1) do
-        EM.stop if ! Rainbows.tick && conns.empty? && EM.reactor_running?
+        if ! Rainbows.tick && conns.empty? && defers_finished? &&
+            EM.reactor_running?
+          EM.stop
+        end
       end
       LISTENERS.map! do |s|
         EM.watch(s, Rainbows::EventMachine::Server) do |c|
diff --git a/t/app_deferred.ru b/t/app_deferred.ru
index a70b33b..b3d7ff1 100644
--- a/t/app_deferred.ru
+++ b/t/app_deferred.ru
@@ -6,12 +6,18 @@
 
 class DeferredApp < Struct.new(:app)
   def deferred?(env)
-    env["PATH_INFO"] == "/deferred"
+    env["PATH_INFO"] =~ %r{\A/deferred}
   end
 
   def call(env)
     env["rack.multithread"] or raise RuntimeError, "rack.multithread not true"
     body = "#{Thread.current.inspect}\n"
+    if env["PATH_INFO"] =~ %r{\A/deferred(\d+)}
+      delay = $1.to_i
+      File.open(ENV['fifo'], 'w') { |fp| fp.write "sleeping #{delay}s\n" }
+      body = "deferred sleep\n"
+      sleep(delay)
+    end
     headers = {
       "Content-Type" => "text/plain",
       "Content-Length" => body.size.to_s,
diff --git a/t/t0700-app-deferred.sh b/t/t0700-app-deferred.sh
index 90614b2..188fdde 100755
--- a/t/t0700-app-deferred.sh
+++ b/t/t0700-app-deferred.sh
@@ -15,7 +15,7 @@ CONFIG_RU=app_deferred.ru
 t_begin "setup and start" && {
 	rainbows_setup
 	rtmpfiles deferred_err deferred_out sync_err sync_out
-	rainbows -D -c $unicorn_config $CONFIG_RU
+	fifo=$fifo rainbows -D -c $unicorn_config $CONFIG_RU
 	rainbows_wait_start
 }
 
@@ -36,8 +36,20 @@ t_begin "deferred requests run in a different thread" && {
 	test x"$(uniq < $deferred_out)" != x"$sync_thread"
 }
 
-t_begin "termination signal sent" && {
-	kill $rainbows_pid
+t_begin "deferred requests run after graceful shutdown" && {
+	# XXX sleeping 5s ought to be enough for SIGQUIT to arrive,
+	# hard to tell with overloaded systems...
+	s=5
+	curl -sSf --no-buffer http://$listen/deferred$s \
+		>$deferred_out 2>$deferred_err &
+	curl_pid=$!
+	msg="$(cat $fifo)"
+	kill -QUIT $rainbows_pid
+	test x"$msg" = x"sleeping ${s}s"
+	wait $curl_pid # for curl to finish
+	test $? -eq 0
+	test ! -s $deferred_err
+	test x"$(cat $deferred_out)" = 'xdeferred sleep'
 }
 
 t_begin "no errors in stderr" && check_stderr
-- 
EW

  parent reply index

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-01-09 13:43 Waiting " alex0375
2017-01-09 19:43 ` Eric Wong
2017-01-09 19:45   ` [PATCH 1/2] tests: re-enable EventMachine tests, again Eric Wong
2017-01-09 19:45   ` Eric Wong [this message]
2017-01-10  7:31   ` Waiting for deferred actions to finish alex0375

Reply instructions:

You may reply publically to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

  List information: https://bogomips.org/rainbows/

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20170109194545.GB16691@starla \
    --to=e@80x24.org \
    --cc=alex0375@gmail.com \
    --cc=rainbows-public@bogomips.org \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link

Rainbows! Rack HTTP server user/dev discussion

Archives are clonable:
	git clone --mirror https://bogomips.org/rainbows-public
	git clone --mirror http://ou63pmih66umazou.onion/rainbows-public

Newsgroups are available over NNTP:
	nntp://news.public-inbox.org/inbox.comp.lang.ruby.rainbows
	nntp://ou63pmih66umazou.onion/inbox.comp.lang.ruby.rainbows

 note: .onion URLs require Tor: https://www.torproject.org/
       or Tor2web: https://www.tor2web.org/

AGPL code for this site: git clone https://public-inbox.org/ public-inbox