From 57ae2f7e2d56a38140ae66915885567d361e240a Mon Sep 17 00:00:00 2001
From: Aleksei Lipniagov <alipniagov@gitlab.com>
Date: Tue, 2 Jul 2019 10:36:33 +0300
Subject: [PATCH] Use separate Prometheus metrics dirs in dev/test

Store Sidekiq and Web server metrics from Prometheus in separate
directories in `development` and `test` environments.
---
 config/initializers/7_prometheus_metrics.rb   | 20 +++++++++++++++----
 tmp/prometheus_multiproc_dir/puma/.gitkeep    |  0
 tmp/prometheus_multiproc_dir/sidekiq/.gitkeep |  0
 tmp/prometheus_multiproc_dir/unicorn/.gitkeep |  0
 4 files changed, 16 insertions(+), 4 deletions(-)
 create mode 100644 tmp/prometheus_multiproc_dir/puma/.gitkeep
 create mode 100644 tmp/prometheus_multiproc_dir/sidekiq/.gitkeep
 create mode 100644 tmp/prometheus_multiproc_dir/unicorn/.gitkeep

diff --git a/config/initializers/7_prometheus_metrics.rb b/config/initializers/7_prometheus_metrics.rb
index 54cdefc2a10..d70d83b24d9 100644
--- a/config/initializers/7_prometheus_metrics.rb
+++ b/config/initializers/7_prometheus_metrics.rb
@@ -1,15 +1,27 @@
 require 'prometheus/client'
 require 'prometheus/client/support/unicorn'
 
+# Keep separate directories for separate processes
+def prometheus_default_multiproc_dir
+  return unless Rails.env.development? || Rails.env.test?
+
+  if Sidekiq.server?
+    Rails.root.join('tmp/prometheus_multiproc_dir/sidekiq')
+  elsif defined?(Unicorn::Worker)
+    Rails.root.join('tmp/prometheus_multiproc_dir/unicorn')
+  elsif defined?(::Puma)
+    Rails.root.join('tmp/prometheus_multiproc_dir/puma')
+  else
+    Rails.root.join('tmp/prometheus_multiproc_dir')
+  end
+end
+
 Prometheus::Client.configure do |config|
   config.logger = Rails.logger
 
   config.initial_mmap_file_size = 4 * 1024
-  config.multiprocess_files_dir = ENV['prometheus_multiproc_dir']
 
-  if Rails.env.development? || Rails.env.test?
-    config.multiprocess_files_dir ||= Rails.root.join('tmp/prometheus_multiproc_dir')
-  end
+  config.multiprocess_files_dir = ENV['prometheus_multiproc_dir'] || prometheus_default_multiproc_dir
 
   config.pid_provider = Prometheus::Client::Support::Unicorn.method(:worker_pid_provider)
 end
diff --git a/tmp/prometheus_multiproc_dir/puma/.gitkeep b/tmp/prometheus_multiproc_dir/puma/.gitkeep
new file mode 100644
index 00000000000..e69de29bb2d
diff --git a/tmp/prometheus_multiproc_dir/sidekiq/.gitkeep b/tmp/prometheus_multiproc_dir/sidekiq/.gitkeep
new file mode 100644
index 00000000000..e69de29bb2d
diff --git a/tmp/prometheus_multiproc_dir/unicorn/.gitkeep b/tmp/prometheus_multiproc_dir/unicorn/.gitkeep
new file mode 100644
index 00000000000..e69de29bb2d