From 4cc8dd41eca45e79ad107dc554bfdfdddbdce958 Mon Sep 17 00:00:00 2001
From: evazion <noizave@gmail.com>
Date: Sun, 12 Sep 2021 07:01:35 -0500
Subject: [PATCH] puma: add rack-timeout gem.

Unlike Unicorn, Puma doesn't have a builtin HTTP request timeout
mechanism, so we have to use Rack::Timeout instead.

See the caveats in the Rack::Timeout documentation [1]. In Unicorn, a
timeout would send a SIGKILL to the worker, immediately killing it. This
would result in a dropped connection and a Cloudflare 502 error to the
user. In Puma, it raises an exception, which we can catch and return a
better error to the user. On the other hand, raising an exception can
potentially corrupt application state if it's sent at the wrong time, or
be delayed indefinitely if the app is stuck in IO or C extension code.

The default request timeout is 65 seconds. 65 seconds is to give things
like HTTP requests on a 60 second timeout enough time to complete. Set
the RACK_REQUEST_TIMEOUT environment variable to change the timeout.

1: https://github.com/sharpstone/rack-timeout#further-documentation
---
 Gemfile                                   |  1 +
 Gemfile.lock                              |  2 ++
 app/controllers/application_controller.rb |  2 ++
 config/initializers/rack_timeout.rb       | 13 +++++++++++++
 4 files changed, 18 insertions(+)
 create mode 100644 config/initializers/rack_timeout.rb

diff --git a/Gemfile b/Gemfile
index 0ecf45756..cb2ef8986 100644
--- a/Gemfile
+++ b/Gemfile
@@ -55,6 +55,7 @@ gem 'newrelic_rpm', require: false
 gem 'clockwork'
 gem 'puma-metrics'
 gem 'puma_worker_killer'
+gem "rack-timeout", require: "rack/timeout/base"
 
 group :production, :staging do
   gem 'unicorn', :platforms => :ruby
diff --git a/Gemfile.lock b/Gemfile.lock
index d5fd2aab6..453514843 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -344,6 +344,7 @@ GEM
       rack
     rack-test (1.1.0)
       rack (>= 1.0, < 3)
+    rack-timeout (0.6.0)
     rails (6.1.4.1)
       actioncable (= 6.1.4.1)
       actionmailbox (= 6.1.4.1)
@@ -568,6 +569,7 @@ DEPENDENCIES
   puma_worker_killer
   pundit
   rack-mini-profiler
+  rack-timeout
   rails (~> 6.0)
   rake
   rakismet
diff --git a/app/controllers/application_controller.rb b/app/controllers/application_controller.rb
index 13bf7f557..22273a652 100644
--- a/app/controllers/application_controller.rb
+++ b/app/controllers/application_controller.rb
@@ -106,6 +106,8 @@ class ApplicationController < ActionController::Base
       render_error_page(422, exception, template: "static/tag_limit_error", message: "You cannot search for more than #{CurrentUser.tag_query_limit} tags at a time.")
     when RateLimiter::RateLimitError
       render_error_page(429, exception)
+    when Rack::Timeout::RequestTimeoutException
+      render_error_page(500, exception, message: "Your request took too long to complete and was canceled.")
     when NotImplementedError
       render_error_page(501, exception, message: "This feature isn't available: #{exception.message}")
     when PG::ConnectionBad
diff --git a/config/initializers/rack_timeout.rb b/config/initializers/rack_timeout.rb
new file mode 100644
index 000000000..e0116aebf
--- /dev/null
+++ b/config/initializers/rack_timeout.rb
@@ -0,0 +1,13 @@
+# https://github.com/sharpstone/rack-timeout#configuring
+options = {
+  service_timeout: ENV.fetch("RACK_REQUEST_TIMEOUT", 65).to_i,
+  wait_timeout: false,
+  wait_overtime: false,
+  service_past_wait: false,
+  term_on_timeout: false
+}
+
+Rack::Timeout::Logger.logger = Rails.logger.dup
+Rack::Timeout::Logger.logger.level = :error
+
+Rails.application.config.middleware.insert_before Rack::Runtime, Rack::Timeout, **options