Merge branch 'custom-events-tracking' into 'master'

Tracking of custom events

## What does this MR do?

This MR adds the ability to track custom events such as the number of Git pushes.

## Are there points in the code the reviewer needs to double check?

The usual stuff.

## Why was this MR needed?

We want to track more business level data such as the number of Git pushes, how many repositories are imported (and from where), etc.

## What are the relevant issue numbers?

gitlab-org/gitlab-ce#13720

## Does this MR meet the acceptance criteria?

- [x] [CHANGELOG](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/CHANGELOG) entry added
- [x] [Documentation created/updated](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/doc/development/doc_styleguide.md)
- [x] ~~API support added~~
- Tests
  - [x] Added for this feature/bug
  - [x] All builds are passing
- [x] Conform by the [style guides](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/CONTRIBUTING.md#style-guides)
- [x] Branch has no merge conflicts with `master` (if you do - rebase it please)
- [x] [Squashed related commits together](https://git-scm.com/book/en/Git-Tools-Rewriting-History#Squashing-Commits)

cc @pcarranza 

See merge request !5830

16 files changed, 219 insertions, 6 deletions

diff --git a/CHANGELOG b/CHANGELOG
index eb078d61c7b..bdc27d77a1a 100644
--- a/CHANGELOG
+++ b/CHANGELOG
@@ -17,6 +17,7 @@ v 8.11.0 (unreleased)
   - API: List access requests, request access, approve, and deny access requests to a project or a group. !4833
   - Use long options for curl examples in documentation !5703 (winniehell)
   - Remove magic comments (`# encoding: UTF-8`) from Ruby files. !5456 (winniehell)
+  - GitLab Performance Monitoring can now track custom events such as the number of tags pushed to a repository
   - Add support for relative links starting with ./ or / to RelativeLinkFilter (winniehell)
   - Ignore URLs starting with // in Markdown links !5677 (winniehell)
   - Fix CI status icon link underline (ClemMakesApps)
diff --git a/app/models/repository.rb b/app/models/repository.rb
index 01b02ccc0dc..2494c266cd2 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.
@@ -1067,4 +1083,8 @@ 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
diff --git a/doc/monitoring/performance/influxdb_schema.md b/doc/monitoring/performance/influxdb_schema.md
index 41861860b6d..eff0e29f58d 100644
--- a/doc/monitoring/performance/influxdb_schema.md
+++ b/doc/monitoring/performance/influxdb_schema.md
@@ -9,6 +9,7 @@ The following measurements are currently stored in InfluxDB:
 - `PROCESS_object_counts`
 - `PROCESS_transactions`
 - `PROCESS_views`
+- `events`
 
 Here, `PROCESS` is replaced with either `rails` or `sidekiq` depending on the
 process type. In all series, any form of duration is stored in milliseconds.
@@ -78,6 +79,14 @@ following value fields are available:
 The `action` tag contains the action name of the transaction that rendered the
 view.
 
+## events
+
+This measurement is used to store generic events such as the number of Git
+pushes, Emails sent, etc. Each point in this measurement has a single value
+field called `count`. The value of this field is simply set to `1`. Each point
+also has at least one tag: `event`. This tag's value is set to the event name.
+Depending on the event type additional tags may be available as well.
+
 ---
 
 Read more on:
diff --git a/lib/ci/api/builds.rb b/lib/ci/api/builds.rb
index 260ac81f5fa..9f3b582a263 100644
--- a/lib/ci/api/builds.rb
+++ b/lib/ci/api/builds.rb
@@ -20,8 +20,13 @@ module Ci
           build = Ci::RegisterBuildService.new.execute(current_runner)
 
           if build
+            Gitlab::Metrics.add_event(:build_found,
+                                      project: build.project.path_with_namespace)
+
             present build, with: Entities::BuildDetails
           else
+            Gitlab::Metrics.add_event(:build_not_found)
+
             not_found!
           end
         end
@@ -42,6 +47,9 @@ module Ci
 
           build.update_attributes(trace: params[:trace]) if params[:trace]
 
+          Gitlab::Metrics.add_event(:update_build,
+                                    project: build.project.path_with_namespace)
+
           case params[:state].to_s
           when 'success'
             build.success
diff --git a/lib/gitlab/metrics.rb b/lib/gitlab/metrics.rb
index 41fcd971c22..3d1ba33ec68 100644
--- a/lib/gitlab/metrics.rb
+++ b/lib/gitlab/metrics.rb
@@ -124,6 +124,15 @@ module Gitlab
       trans.action = action if trans
     end
 
+    # Tracks an event.
+    #
+    # See `Gitlab::Metrics::Transaction#add_event` for more details.
+    def self.add_event(*args)
+      trans = current_transaction
+
+      trans.add_event(*args) if trans
+    end
+
     # Returns the prefix to use for the name of a series.
     def self.series_prefix
       @series_prefix ||= Sidekiq.server? ? 'sidekiq_' : 'rails_'
diff --git a/lib/gitlab/metrics/metric.rb b/lib/gitlab/metrics/metric.rb
index f23d67e1e38..bd0afe53c51 100644
--- a/lib/gitlab/metrics/metric.rb
+++ b/lib/gitlab/metrics/metric.rb
@@ -4,15 +4,20 @@ module Gitlab
     class Metric
       JITTER_RANGE = 0.000001..0.001
 
-      attr_reader :series, :values, :tags
+      attr_reader :series, :values, :tags, :type
 
       # series - The name of the series (as a String) to store the metric in.
       # values - A Hash containing the values to store.
       # tags   - A Hash containing extra tags to add to the metrics.
-      def initialize(series, values, tags = {})
+      def initialize(series, values, tags = {}, type = :metric)
         @values = values
         @series = series
         @tags   = tags
+        @type   = type
+      end
+
+      def event?
+        type == :event
       end
 
       # Returns a Hash in a format that can be directly written to InfluxDB.
diff --git a/lib/gitlab/metrics/rack_middleware.rb b/lib/gitlab/metrics/rack_middleware.rb
index e61670f491c..b4493bf44d2 100644
--- a/lib/gitlab/metrics/rack_middleware.rb
+++ b/lib/gitlab/metrics/rack_middleware.rb
@@ -17,6 +17,10 @@ module Gitlab
         begin
           retval = trans.run { @app.call(env) }
 
+        rescue Exception => error # rubocop: disable Lint/RescueException
+          trans.add_event(:rails_exception)
+
+          raise error
         # Even in the event of an error we want to submit any metrics we
         # might've gathered up to this point.
         ensure
diff --git a/lib/gitlab/metrics/sidekiq_middleware.rb b/lib/gitlab/metrics/sidekiq_middleware.rb
index a1240fd33ee..f9dd8e41912 100644
--- a/lib/gitlab/metrics/sidekiq_middleware.rb
+++ b/lib/gitlab/metrics/sidekiq_middleware.rb
@@ -11,6 +11,10 @@ module Gitlab
           # Old gitlad-shell messages don't provide enqueued_at/created_at attributes
           trans.set(:sidekiq_queue_duration, Time.now.to_f - (message['enqueued_at'] || message['created_at'] || 0))
           trans.run { yield }
+        rescue Exception => error # rubocop: disable Lint/RescueException
+          trans.add_event(:sidekiq_exception)
+
+          raise error
         ensure
           trans.finish
         end
diff --git a/lib/gitlab/metrics/transaction.rb b/lib/gitlab/metrics/transaction.rb
index 968f3218950..7bc16181be6 100644
--- a/lib/gitlab/metrics/transaction.rb
+++ b/lib/gitlab/metrics/transaction.rb
@@ -4,7 +4,10 @@ module Gitlab
     class Transaction
       THREAD_KEY = :_gitlab_metrics_transaction
 
-      attr_reader :tags, :values, :methods
+      # The series to store events (e.g. Git pushes) in.
+      EVENT_SERIES = 'events'
+
+      attr_reader :tags, :values, :method, :metrics
 
       attr_accessor :action
 
@@ -55,6 +58,20 @@ module Gitlab
         @metrics << Metric.new("#{Metrics.series_prefix}#{series}", values, tags)
       end
 
+      # Tracks a business level event
+      #
+      # Business level events including events such as Git pushes, Emails being
+      # sent, etc.
+      #
+      # event_name - The name of the event (e.g. "git_push").
+      # tags - A set of tags to attach to the event.
+      def add_event(event_name, tags = {})
+        @metrics << Metric.new(EVENT_SERIES,
+                               { count: 1 },
+                               { event: event_name }.merge(tags),
+                               :event)
+      end
+
       # Returns a MethodCall object for the given name.
       def method_call_for(name)
         unless method = @methods[name]
@@ -101,7 +118,7 @@ module Gitlab
         submit_hashes = submit.map do |metric|
           hash = metric.to_hash
 
-          hash[:tags][:action] ||= @action if @action
+          hash[:tags][:action] ||= @action if @action && !metric.event?
 
           hash
         end
diff --git a/spec/lib/gitlab/metrics/metric_spec.rb b/spec/lib/gitlab/metrics/metric_spec.rb
index f718d536130..f26fca52c50 100644
--- a/spec/lib/gitlab/metrics/metric_spec.rb
+++ b/spec/lib/gitlab/metrics/metric_spec.rb
@@ -23,6 +23,24 @@ describe Gitlab::Metrics::Metric do
     it { is_expected.to eq({ host: 'localtoast' }) }
   end
 
+  describe '#type' do
+    subject { metric.type }
+
+    it { is_expected.to eq(:metric) }
+  end
+
+  describe '#event?' do
+    it 'returns false for a regular metric' do
+      expect(metric.event?).to eq(false)
+    end
+
+    it 'returns true for an event metric' do
+      expect(metric).to receive(:type).and_return(:event)
+
+      expect(metric.event?).to eq(true)
+    end
+  end
+
   describe '#to_hash' do
     it 'returns a Hash' do
       expect(metric.to_hash).to be_an_instance_of(Hash)
diff --git a/spec/lib/gitlab/metrics/rack_middleware_spec.rb b/spec/lib/gitlab/metrics/rack_middleware_spec.rb
index f264ed64029..a30cb2a5e38 100644
--- a/spec/lib/gitlab/metrics/rack_middleware_spec.rb
+++ b/spec/lib/gitlab/metrics/rack_middleware_spec.rb
@@ -45,6 +45,15 @@ describe Gitlab::Metrics::RackMiddleware do
 
       middleware.call(env)
     end
+
+    it 'tracks any raised exceptions' do
+      expect(app).to receive(:call).with(env).and_raise(RuntimeError)
+
+      expect_any_instance_of(Gitlab::Metrics::Transaction).
+        to receive(:add_event).with(:rails_exception)
+
+      expect { middleware.call(env) }.to raise_error(RuntimeError)
+    end
   end
 
   describe '#transaction_from_env' do
diff --git a/spec/lib/gitlab/metrics/sidekiq_middleware_spec.rb b/spec/lib/gitlab/metrics/sidekiq_middleware_spec.rb
index 4d2aa03e722..acaba785606 100644
--- a/spec/lib/gitlab/metrics/sidekiq_middleware_spec.rb
+++ b/spec/lib/gitlab/metrics/sidekiq_middleware_spec.rb
@@ -12,7 +12,9 @@ describe Gitlab::Metrics::SidekiqMiddleware do
         with('TestWorker#perform').
         and_call_original
 
-      expect_any_instance_of(Gitlab::Metrics::Transaction).to receive(:set).with(:sidekiq_queue_duration, instance_of(Float))
+      expect_any_instance_of(Gitlab::Metrics::Transaction).to receive(:set).
+        with(:sidekiq_queue_duration, instance_of(Float))
+
       expect_any_instance_of(Gitlab::Metrics::Transaction).to receive(:finish)
 
       middleware.call(worker, message, :test) { nil }
@@ -25,10 +27,28 @@ describe Gitlab::Metrics::SidekiqMiddleware do
         with('TestWorker#perform').
         and_call_original
 
-      expect_any_instance_of(Gitlab::Metrics::Transaction).to receive(:set).with(:sidekiq_queue_duration, instance_of(Float))
+      expect_any_instance_of(Gitlab::Metrics::Transaction).to receive(:set).
+        with(:sidekiq_queue_duration, instance_of(Float))
+
       expect_any_instance_of(Gitlab::Metrics::Transaction).to receive(:finish)
 
       middleware.call(worker, {}, :test) { nil }
     end
+
+    it 'tracks any raised exceptions' do
+      worker = double(:worker, class: double(:class, name: 'TestWorker'))
+
+      expect_any_instance_of(Gitlab::Metrics::Transaction).
+        to receive(:run).and_raise(RuntimeError)
+
+      expect_any_instance_of(Gitlab::Metrics::Transaction).
+        to receive(:add_event).with(:sidekiq_exception)
+
+      expect_any_instance_of(Gitlab::Metrics::Transaction).
+        to receive(:finish)
+
+      expect { middleware.call(worker, message, :test) }.
+        to raise_error(RuntimeError)
+    end
   end
 end
diff --git a/spec/lib/gitlab/metrics/transaction_spec.rb b/spec/lib/gitlab/metrics/transaction_spec.rb
index f1a191d9410..3887c04c832 100644
--- a/spec/lib/gitlab/metrics/transaction_spec.rb
+++ b/spec/lib/gitlab/metrics/transaction_spec.rb
@@ -142,5 +142,62 @@ describe Gitlab::Metrics::Transaction do
 
       transaction.submit
     end
+
+    it 'does not add an action tag for events' do
+      transaction.action = 'Foo#bar'
+      transaction.add_event(:meow)
+
+      hash = {
+        series:    'events',
+        tags:      { event: :meow },
+        values:    { count: 1 },
+        timestamp: an_instance_of(Fixnum)
+      }
+
+      expect(Gitlab::Metrics).to receive(:submit_metrics).
+        with([hash])
+
+      transaction.submit
+    end
+  end
+
+  describe '#add_event' do
+    it 'adds a metric' do
+      transaction.add_event(:meow)
+
+      expect(transaction.metrics[0]).to be_an_instance_of(Gitlab::Metrics::Metric)
+    end
+
+    it "does not prefix the metric's series name" do
+      transaction.add_event(:meow)
+
+      metric = transaction.metrics[0]
+
+      expect(metric.series).to eq(described_class::EVENT_SERIES)
+    end
+
+    it 'tracks a counter for every event' do
+      transaction.add_event(:meow)
+
+      metric = transaction.metrics[0]
+
+      expect(metric.values).to eq(count: 1)
+    end
+
+    it 'tracks the event name' do
+      transaction.add_event(:meow)
+
+      metric = transaction.metrics[0]
+
+      expect(metric.tags).to eq(event: :meow)
+    end
+
+    it 'allows tracking of custom tags' do
+      transaction.add_event(:meow, animal: 'cat')
+
+      metric = transaction.metrics[0]
+
+      expect(metric.tags).to eq(event: :meow, animal: 'cat')
+    end
   end
 end
diff --git a/spec/lib/gitlab/metrics_spec.rb b/spec/lib/gitlab/metrics_spec.rb
index 84f9475a0f8..ab6e311b1e8 100644
--- a/spec/lib/gitlab/metrics_spec.rb
+++ b/spec/lib/gitlab/metrics_spec.rb
@@ -153,4 +153,28 @@ describe Gitlab::Metrics do
       expect(described_class.series_prefix).to be_an_instance_of(String)
     end
   end
+
+  describe '.add_event' do
+    context 'without a transaction' do
+      it 'does nothing' do
+        expect_any_instance_of(Gitlab::Metrics::Transaction).
+          not_to receive(:add_event)
+
+        Gitlab::Metrics.add_event(:meow)
+      end
+    end
+
+    context 'with a transaction' do
+      it 'adds an event' do
+        transaction = Gitlab::Metrics::Transaction.new
+
+        expect(transaction).to receive(:add_event).with(:meow)
+
+        expect(Gitlab::Metrics).to receive(:current_transaction).
+          and_return(transaction)
+
+        Gitlab::Metrics.add_event(:meow)
+      end
+    end
+  end
 end