Add rbtrace to Gemfilesh-include-rbtrace

This will be enabled if ENABLE_RBTRACE environment variable is defined.
This will allow us to debug all sorts of issues in production:

https://github.com/tmm1/rbtrace

6 files changed, 34 insertions, 0 deletions

diff --git a/Gemfile b/Gemfile
index 47815f230d3..a7bf5c500ca 100644
--- a/Gemfile
+++ b/Gemfile
@@ -400,6 +400,7 @@ gem 'email_reply_trimmer', '~> 0.1'
 gem 'html2text'
 
 gem 'ruby-prof', '~> 0.17.0'
+gem 'rbtrace', '~> 0.4', require: false
 
 # OAuth
 gem 'oauth2', '~> 1.4'
diff --git a/Gemfile.lock b/Gemfile.lock
index 22626c0071b..2a8b2579605 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -700,6 +700,10 @@ GEM
       ffi (>= 0.5.0, < 2)
     rblineprof (0.3.6)
       debugger-ruby_core_source (~> 1.3)
+    rbtrace (0.4.10)
+      ffi (>= 1.0.6)
+      msgpack (>= 0.4.3)
+      trollop (>= 1.16.2)
     rdoc (6.0.4)
     re2 (1.1.1)
     recaptcha (3.0.0)
@@ -911,6 +915,7 @@ GEM
       parslet (~> 1.5.0)
     toml-rb (1.0.0)
       citrus (~> 3.0, > 3.0)
+    trollop (2.1.3)
     truncato (0.7.10)
       htmlentities (~> 4.3.1)
       nokogiri (~> 1.8.0, >= 1.7.0)
@@ -1133,6 +1138,7 @@ DEPENDENCIES
   rainbow (~> 2.2)
   raindrops (~> 0.18)
   rblineprof (~> 0.3.6)
+  rbtrace (~> 0.4)
   rdoc (~> 6.0)
   re2 (~> 1.1.1)
   recaptcha (~> 3.0)
diff --git a/Gemfile.rails5.lock b/Gemfile.rails5.lock
index 5a0aaf05608..36d758f0558 100644
--- a/Gemfile.rails5.lock
+++ b/Gemfile.rails5.lock
@@ -709,6 +709,10 @@ GEM
       ffi (>= 0.5.0, < 2)
     rblineprof (0.3.6)
       debugger-ruby_core_source (~> 1.3)
+    rbtrace (0.4.10)
+      ffi (>= 1.0.6)
+      msgpack (>= 0.4.3)
+      trollop (>= 1.16.2)
     rdoc (6.0.4)
     re2 (1.1.1)
     recaptcha (3.0.0)
@@ -918,6 +922,7 @@ GEM
       parslet (~> 1.5.0)
     toml-rb (1.0.0)
       citrus (~> 3.0, > 3.0)
+    trollop (2.1.3)
     truncato (0.7.10)
       htmlentities (~> 4.3.1)
       nokogiri (~> 1.8.0, >= 1.7.0)
@@ -1144,6 +1149,7 @@ DEPENDENCIES
   rainbow (~> 2.2)
   raindrops (~> 0.18)
   rblineprof (~> 0.3.6)
+  rbtrace (~> 0.4)
   rdoc (~> 6.0)
   re2 (~> 1.1.1)
   recaptcha (~> 3.0)
diff --git a/changelogs/unreleased/sh-include-rbtrace.yml b/changelogs/unreleased/sh-include-rbtrace.yml
new file mode 100644
index 00000000000..41f0655e3f8
--- /dev/null
+++ b/changelogs/unreleased/sh-include-rbtrace.yml
@@ -0,0 +1,5 @@
+---
+title: Add rbtrace to Gemfile
+merge_request: 20831
+author:
+type: other
diff --git a/config/initializers/rbtrace.rb b/config/initializers/rbtrace.rb
new file mode 100644
index 00000000000..3a076c99ad0
--- /dev/null
+++ b/config/initializers/rbtrace.rb
@@ -0,0 +1,3 @@
+# frozen_string_literal: true
+
+require 'rbtrace' if ENV['ENABLE_RBTRACE']
diff --git a/doc/administration/troubleshooting/debug.md b/doc/administration/troubleshooting/debug.md
index 83a714810c1..7ae4f7c1515 100644
--- a/doc/administration/troubleshooting/debug.md
+++ b/doc/administration/troubleshooting/debug.md
@@ -66,6 +66,19 @@ On CentOS:
 sudo yum install gdb
 ```
 
+### rbtrace
+
+GitLab 11.2 ships with [rbtrace](https://github.com/tmm1/rbtrace), which
+allows you to trace Ruby code, view all running threads, take memory dumps,
+and more. However, this is not enabled by default. To enable it, define the
+`ENABLE_RBTRACE` variable to the environment. For example, in Omnibus:
+
+```ruby
+gitlab_rails['env'] = {"ENABLE_RBTRACE" => "1"}
+```
+
+Then reconfigure the system and restart Unicorn and Sidekiq.
+
 ## Common Problems
 
 Many of the tips to diagnose issues below apply to many different situations. We'll use one