unicorn Ruby/Rack server user+dev discussion/patches/pulls/bugs/help
 help / color / mirror / code / Atom feed
From: Jeremy Evans <code@jeremyevans.net>
To: unicorn-public@bogomips.org
Subject: Patch: Add after_worker_exit configuration option
Date: Tue, 21 Feb 2017 11:19:23 -0800	[thread overview]
Message-ID: <20170221191923.GH93742@jeremyevans.local> (raw)

This option can be used to implement custom behavior for handling
worker exits.  For example, let's say you have a specific request
that crashes a worker process, which you expect to be due to a
improperly programmed C extension. By modifying your worker to
save request related data in a temporary file and using this option,
you can get a record of what request is crashing the application,
which will make debugging easier.

This is not a complete patch as it doesn't include tests, but
before writing tests I wanted to see if this is something you'd
consider including in unicorn.

Example:

after_worker_exit do |server, worker, status|
  server.logger.info "worker #{status.success? ? 'exit' : 'crash'}: #{status}"

  file = "request.#{status.pid}.txt"
  if File.exist?(file)
    do_something_with(File.read(file)) unless status.success?
    File.delete(file)
  end
end
---
 lib/unicorn/configurator.rb | 14 ++++++++++++++
 lib/unicorn/http_server.rb  |  6 +++---
 2 files changed, 17 insertions(+), 3 deletions(-)

diff --git a/lib/unicorn/configurator.rb b/lib/unicorn/configurator.rb
index 3329c10..81589b0 100644
--- a/lib/unicorn/configurator.rb
+++ b/lib/unicorn/configurator.rb
@@ -41,6 +41,14 @@ class Unicorn::Configurator
     :before_exec => lambda { |server|
         server.logger.info("forked child re-executing...")
       },
+    :after_worker_exit => lambda { |server, worker, status|
+        m = "reaped #{status.inspect} worker=#{worker.nr rescue 'unknown'}"
+        if status.success?
+          server.logger.info(m)
+        else
+          server.logger.error(m)
+        end
+      },
     :pid => nil,
     :preload_app => false,
     :check_client_connection => false,
@@ -151,6 +159,12 @@ def after_fork(*args, &block)
     set_hook(:after_fork, block_given? ? block : args[0])
   end
 
+  # sets after_worker_exit hook to a given block.  This block will be called
+  # by the master process after a worker exits.
+  def after_worker_exit(*args, &block)
+    set_hook(:after_worker_exit, block_given? ? block : args[0], 3)
+  end
+
   # sets before_fork got be a given Proc object.  This Proc
   # object will be called by the master process before forking
   # each worker.
diff --git a/lib/unicorn/http_server.rb b/lib/unicorn/http_server.rb
index 35bd100..567ee0e 100644
--- a/lib/unicorn/http_server.rb
+++ b/lib/unicorn/http_server.rb
@@ -14,7 +14,8 @@ class Unicorn::HttpServer
   attr_accessor :app, :timeout, :worker_processes,
                 :before_fork, :after_fork, :before_exec,
                 :listener_opts, :preload_app,
-                :orig_app, :config, :ready_pipe, :user
+                :orig_app, :config, :ready_pipe, :user,
+                :after_worker_exit
 
   attr_reader :pid, :logger
   include Unicorn::SocketHelper
@@ -395,8 +396,7 @@ def reap_all_workers
         proc_name 'master'
       else
         worker = @workers.delete(wpid) and worker.close rescue nil
-        m = "reaped #{status.inspect} worker=#{worker.nr rescue 'unknown'}"
-        status.success? ? logger.info(m) : logger.error(m)
+        after_worker_exit.call(self, worker, status)
       end
     rescue Errno::ECHILD
       break
-- 
2.11.0


             reply	other threads:[~2017-02-21 19:19 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-02-21 19:19 Jeremy Evans [this message]
2017-02-21 19:43 ` Patch: Add after_worker_exit configuration option Eric Wong
2017-02-21 20:02   ` Jeremy Evans
2017-02-21 20:15     ` Eric Wong
2017-02-21 20:49       ` Jeremy Evans
2017-02-21 21:38         ` Eric Wong

Reply instructions:

You may reply publicly 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://yhbt.net/unicorn/

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

  git send-email \
    --in-reply-to=20170221191923.GH93742@jeremyevans.local \
    --to=code@jeremyevans.net \
    --cc=unicorn-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
Be sure your reply has a Subject: header at the top and a blank line before the message body.
Code repositories for project(s) associated with this public inbox

	https://yhbt.net/unicorn.git/

This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for read-only IMAP folder(s) and NNTP newsgroup(s).