Tracking of custom events

GitLab Performance Monitoring is now able to track custom events not
directly related to application performance. These events include the
number of tags pushed, repositories created, builds registered, etc.

The use of these events is to get a better overview of how a GitLab
instance is used and how that may affect performance. For example, a
large number of Git pushes may have a negative impact on the underlying
storage engine.

Events are stored in the "events" measurement and are not prefixed with
"rails_" or "sidekiq_", this makes it easier to query events with the
same name triggered from different parts of the application. All events
being stored in the same measurement also makes it easier to downsample
data.

Currently the following events are tracked:

* Creating repositories
* Removing repositories
* Changing the default branch of a repository
* Pushing a new tag
* Removing an existing tag
* Pushing a commit (along with the branch being pushed to)
* Pushing a new branch
* Removing an existing branch
* Importing a repository (along with the URL we're importing)
* Forking a repository (along with the source/target path)
* CI builds registered (and when no build could be found)
* CI builds being updated
* Rails and Sidekiq exceptions

Fixes gitlab-org/gitlab-ce#13720

3 files changed, 28 insertions, 0 deletions

diff --git a/app/models/repository.rb b/app/models/repository.rb
index e56bac509a4..916843dabdd 100644
--- a/app/models/repository.rb
+++ b/app/models/repository.rb
@@ -391,6 +391,8 @@ class Repository
     expire_exists_cache
     expire_root_ref_cache
     expire_emptiness_caches
+
+    repository_event(:create_repository)
   end
 
   # Runs code just before a repository is deleted.
@@ -407,6 +409,8 @@ class Repository
     expire_root_ref_cache
     expire_emptiness_caches
     expire_exists_cache
+
+    repository_event(:remove_repository)
   end
 
   # Runs code just before the HEAD of a repository is changed.
@@ -414,6 +418,8 @@ class Repository
     # Cached divergent commit counts are based on repository head
     expire_branch_cache
     expire_root_ref_cache
+
+    repository_event(:change_default_branch)
   end
 
   # Runs code before pushing (= creating or removing) a tag.
@@ -421,12 +427,16 @@ class Repository
     expire_cache
     expire_tags_cache
     expire_tag_count_cache
+
+    repository_event(:push_tag)
   end
 
   # Runs code before removing a tag.
   def before_remove_tag
     expire_tags_cache
     expire_tag_count_cache
+
+    repository_event(:remove_tag)
   end
 
   def before_import
@@ -443,6 +453,8 @@ class Repository
   # Runs code after a new commit has been pushed.
   def after_push_commit(branch_name, revision)
     expire_cache(branch_name, revision)
+
+    repository_event(:push_commit, branch: branch_name)
   end
 
   # Runs code after a new branch has been created.
@@ -450,11 +462,15 @@ class Repository
     expire_branches_cache
     expire_has_visible_content_cache
     expire_branch_count_cache
+
+    repository_event(:push_branch)
   end
 
   # Runs code before removing an existing branch.
   def before_remove_branch
     expire_branches_cache
+
+    repository_event(:remove_branch)
   end
 
   # Runs code after an existing branch has been removed.
@@ -1059,4 +1075,8 @@ class Repository
   def keep_around_ref_name(sha)
     "refs/keep-around/#{sha}"
   end
+
+  def repository_event(event, tags = {})
+    Gitlab::Metrics.add_event(event, { path: path_with_namespace }.merge(tags))
+  end
 end
diff --git a/app/workers/repository_fork_worker.rb b/app/workers/repository_fork_worker.rb
index d69d6037053..61ed1c38ac4 100644
--- a/app/workers/repository_fork_worker.rb
+++ b/app/workers/repository_fork_worker.rb
@@ -5,6 +5,10 @@ class RepositoryForkWorker
   sidekiq_options queue: :gitlab_shell
 
   def perform(project_id, forked_from_repository_storage_path, source_path, target_path)
+    Gitlab::Metrics.add_event(:fork_repository,
+                              source_path: source_path,
+                              target_path: target_path)
+
     project = Project.find_by_id(project_id)
 
     unless project.present?
diff --git a/app/workers/repository_import_worker.rb b/app/workers/repository_import_worker.rb
index 7d819fe78f8..e6701078f71 100644
--- a/app/workers/repository_import_worker.rb
+++ b/app/workers/repository_import_worker.rb
@@ -10,6 +10,10 @@ class RepositoryImportWorker
     @project = Project.find(project_id)
     @current_user = @project.creator
 
+    Gitlab::Metrics.add_event(:import_repository,
+                              import_url: @project.import_url,
+                              path: @project.path_with_namespace)
+
     result = Projects::ImportService.new(project, current_user).execute
 
     if result[:status] == :error