Implements Web IDE commits counter in Redis

This makes a temporary implementation of the
Web IDE commits counter using Redis while
https://gitlab.com/gitlab-org/gitlab-ce/issues/52096
is being discussed further for a more generic
approach to counters

app/models/usage_counters.rb

-# frozen_string_literal: true
-
-class UsageCounters < ActiveRecord::Base
-  RECORD_LIMIT = 1.freeze
-  BY = 1.freeze
-  BLACKLIST_ATTRIBUTES = %w(id created_at updated_at).freeze
-
-  validate :ensure_only_one, on: :create
-
-  default_value_for :web_ide_commits, 0
-
-  # This method supports concurrency so that several
-  # requests are able to increment the counter without
-  # us having inconsistent data
-  def increment_counters(attrs)
-    # We want to be able to use the service to increment
-    # both a single and multiple counters
-    attrs = Array(attrs)
-
-    attrs_with_by =
-      attrs.each_with_object({}) do |attr, hsh|
-        hsh[attr] = BY
-      end
-
-    self.class.update_counters(id, attrs_with_by)
-  end
-
-  # Every attribute in this table except the blacklisted
-  # attributes is a counter
-  def totals
-    attributes.except(*BLACKLIST_ATTRIBUTES).symbolize_keys
-  end
-
-  private
-
-  # We only want one UsageCounters per instance
-  def ensure_only_one
-    return unless UsageCounters.count >= RECORD_LIMIT
-
-    errors.add(:base, 'There can only be one usage counters record per instance')
-  end
-end

db/migrate/20180929102611_create_usage_counters.rb

-# frozen_string_literal: true
-
-class CreateUsageCounters < ActiveRecord::Migration
-  DOWNTIME = false
-
-  def change
-    create_table :usage_counters do |t|
-      t.integer :web_ide_commits
-
-      t.timestamps_with_timezone null: false
-    end
-  end
-end

db/schema.rb

@@ -11,7 +11,7 @@
 #
 # It's strongly recommended that you check this file into your version control system.
-ActiveRecord::Schema.define(version: 20180929102611) do
+ActiveRecord::Schema.define(version: 20180917172041) do
   # These are extensions that must be enabled in order to support this database
   enable_extension "plpgsql"
@@ -2080,12 +2080,6 @@ ActiveRecord::Schema.define(version: 20180929102611) do
   add_index "uploads", ["model_id", "model_type"], name: "index_uploads_on_model_id_and_model_type", using: :btree
   add_index "uploads", ["uploader", "path"], name: "index_uploads_on_uploader_and_path", using: :btree
-  create_table "usage_counters", force: :cascade do |t|
-    t.integer "web_ide_commits"
-    t.datetime_with_timezone "created_at", null: false
-    t.datetime_with_timezone "updated_at", null: false
-  end
-
   create_table "user_agent_details", force: :cascade do |t|
     t.string "user_agent", null: false
     t.string "ip_address", null: false

lib/api/commits.rb

@@ -109,7 +109,7 @@ module API
         if result[:status] == :success
           commit_detail = user_project.repository.commit(result[:result])
-          UsageCounters.first_or_create.increment_counters(:web_ide_commits) if find_user_from_warden
+          Gitlab::WebIdeCommitsCounter.increment if find_user_from_warden
           present commit_detail, with: Entities::CommitDetail
         else

lib/gitlab/usage_data.rb

@@ -108,7 +108,9 @@ module Gitlab
       end
       def usage_counters
-        UsageCounters.first_or_create.totals
+        {
+          web_ide_commits: Gitlab::WebIdeCommitsCounter.total_count
+        }
       end
       def components_usage_data

lib/gitlab/web_ide_commits_counter.rb

+# frozen_string_literal: true
+
+module Gitlab
+  module WebIdeCommitsCounter
+    WEB_IDE_COMMITS_KEY = "WEB_IDE_COMMITS_COUNT".freeze
+
+    class << self
+      def increment
+        Gitlab::Redis::SharedState.with { |redis| redis.incr(WEB_IDE_COMMITS_KEY) }
+      end
+
+      def total_count
+        Gitlab::Redis::SharedState.with { |redis| redis.get(WEB_IDE_COMMITS_KEY).to_i }
+      end
+    end
+  end
+end

spec/factories/usage_counters.rb

-# frozen_string_literal: true
-
-FactoryBot.define do
-  factory :usage_counters, class: 'UsageCounters' do
-  end
-end

spec/lib/gitlab/import_export/all_models.yml

@@ -330,6 +330,3 @@ resource_label_events:
 - merge_request
 - epic
 - label
-usage_counters:
-- project
-- web_ide_commits

spec/lib/gitlab/web_ide_commits_counter_spec.rb

+# frozen_string_literal: true
+
+require 'spec_helper'
+
+describe Gitlab::WebIdeCommitsCounter, :clean_gitlab_redis_shared_state do
+  describe '.increment' do
+    it 'increments the web ide commits counter by 1' do
+      expect do
+        described_class.increment
+      end.to change { described_class.total_count }.from(0).to(1)
+    end
+  end
+
+  describe '.total_count' do
+    it 'returns the total amount of web ide commits' do
+      expect(described_class.total_count).to eq(0)
+    end
+  end
+end

spec/models/usage_counters_spec.rb

-# frozen_string_literal: true
-
-require 'spec_helper'
-
-describe UsageCounters do
-  let!(:usage_counters) { create(:usage_counters) }
-
-  describe 'maximum number of records' do
-    it 'allows for one single record to be created' do
-      expect do
-        described_class.create!
-      end.to raise_error(ActiveRecord::RecordInvalid, 'Validation failed: There can only be one usage counters record per instance')
-    end
-  end
-
-  describe '#totals' do
-    subject { usage_counters.totals }
-
-    it 'returns counters' do
-      is_expected.to include(web_ide_commits: 0)
-    end
-  end
-
-  describe '#increment_counters' do
-    it 'increments specified counters by 1' do
-      expect do
-        usage_counters.increment_counters(:web_ide_commits)
-      end.to change { usage_counters.reload.web_ide_commits }.from(0).to(1)
-    end
-  end
-end

spec/requests/api/commits_spec.rb

@@ -279,9 +279,9 @@ describe API::Commits do
       end
       it 'does not increment the usage counters using access token authentication' do
-        post api(url, user), valid_c_params
-        expect_any_instance_of(::UsageCounters).not_to receive(:increment_counters)
+        expect(::Gitlab::WebIdeCommitsCounter).not_to receive(:increment)
+        post api(url, user), valid_c_params
       end
       it 'a new file in project repo' do

spec/services/projects/usage_counters_increment_service_spec.rb

-# frozen_string_literal: true
-
-require 'spec_helper'
-
-describe Projects::UsageCountersIncrementService do
-  let(:project) { create(:usage_counters) }
-
-  subject(:service) { described_class.new(project) }
-
-  context '#execute' do
-    context 'when single attribute is passed' do
-      it 'increments attribute' do
-        expect do
-          service.execute(:web_ide_commits)
-        end.to change { project.usage_counters.reload.web_ide_commits }.from(0).to(1)
-      end
-    end
-
-    context 'when array is passed' do
-      it 'increments specified attributes' do
-        expect do
-          service.execute(%i(web_ide_commits))
-        end.to change { project.usage_counters.reload.web_ide_commits }.from(0).to(1)
-      end
-    end
-  end
-end