Load pipeline status for a project in batch from redis

This is a port of
https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/10785 to EE.

app/helpers/projects_helper.rb

@@ -166,6 +166,11 @@ module ProjectsHelper
     key
   end
 
+  def load_pipeline_status(projects)
+    Gitlab::Cache::Ci::ProjectPipelineStatus.
+      load_in_batch_for_projects(projects)
+  end
+
   private
 
   def repo_children_classes(field)

app/models/project.rb

@@ -71,6 +71,7 @@ class Project < ActiveRecord::Base
 
   attr_accessor :new_default_branch
   attr_accessor :old_path_with_namespace
+  attr_writer :pipeline_status
 
   alias_attribute :title, :name
 
@@ -1386,6 +1387,7 @@ class Project < ActiveRecord::Base
     end
   end
 
+  # Lazy loading of the `pipeline_status` attribute
   def pipeline_status
     @pipeline_status ||= Gitlab::Cache::Ci::ProjectPipelineStatus.load_for_project(self)
   end

app/views/shared/projects/_list.html.haml

@@ -7,6 +7,7 @@
 - skip_namespace = false unless local_assigns[:skip_namespace] == true
 - show_last_commit_as_description = false unless local_assigns[:show_last_commit_as_description] == true
 - remote = false unless local_assigns[:remote] == true
+- load_pipeline_status(projects)
 
 .js-projects-list-holder
   - if projects.any?

changelogs/unreleased/27376-bvl-load-pipelinestatus-in-batch.yml

+---
+title: Fetch pipeline status in batch from redis
+merge_request: 10785
+author:

lib/gitlab/cache/ci/project_pipeline_status.rb

@@ -15,18 +15,51 @@ module Gitlab
           end
         end
 
+        def self.load_in_batch_for_projects(projects)
+          cached_results_for_projects(projects).zip(projects).each do |result, project|
+            project.pipeline_status = new(project, result)
+            project.pipeline_status.load_status
+          end
+        end
+
+        def self.cached_results_for_projects(projects)
+          result = Gitlab::Redis.with do |redis|
+            redis.multi do
+              projects.each do |project|
+                cache_key = cache_key_for_project(project)
+                redis.exists(cache_key)
+                redis.hmget(cache_key, :sha, :status, :ref)
+              end
+            end
+          end
+
+          result.each_slice(2).map do |(cache_key_exists, (sha, status, ref))|
+            pipeline_info = { sha: sha, status: status, ref: ref }
+            { loaded_from_cache: cache_key_exists, pipeline_info: pipeline_info }
+          end
+        end
+
+        def self.cache_key_for_project(project)
+          "projects/#{project.id}/pipeline_status"
+        end
+
         def self.update_for_pipeline(pipeline)
-          new(pipeline.project,
+          pipeline_info = {
             sha: pipeline.sha,
             status: pipeline.status,
-              ref: pipeline.ref).store_in_cache_if_needed
+            ref: pipeline.ref
+          }
+
+          new(pipeline.project, pipeline_info: pipeline_info).
+            store_in_cache_if_needed
         end
 
-        def initialize(project, sha: nil, status: nil, ref: nil)
+        def initialize(project, pipeline_info: {}, loaded_from_cache: nil)
           @project = project
-          @sha = sha
-          @ref = ref
-          @status = status
+          @sha = pipeline_info[:sha]
+          @ref = pipeline_info[:ref]
+          @status = pipeline_info[:status]
+          @loaded = loaded_from_cache
         end
 
         def has_status?
@@ -85,6 +118,8 @@ module Gitlab
         end
 
         def has_cache?
+          return self.loaded unless self.loaded.nil?
+
           Gitlab::Redis.with do |redis|
             redis.exists(cache_key)
           end
@@ -95,7 +130,7 @@ module Gitlab
         end
 
         def cache_key
-          "projects/#{project.id}/build_status"
+          self.class.cache_key_for_project(project)
         end
       end
     end

spec/helpers/ci_status_helper_spec.rb

@@ -21,8 +21,10 @@ describe CiStatusHelper do
     it "builds a cache key for pipeline status" do
       pipeline_status = Gitlab::Cache::Ci::ProjectPipelineStatus.new(
         build(:project),
+        pipeline_info: {
           sha: "123abc",
           status: "success"
+        }
       )
       expect(helper.pipeline_status_cache_key(pipeline_status)).to eq("pipeline-status/123abc-success")
     end

spec/helpers/projects_helper_spec.rb

@@ -103,6 +103,18 @@ describe ProjectsHelper do
     end
   end
 
+  describe '#load_pipeline_status' do
+    it 'loads the pipeline status in batch' do
+      project = build(:empty_project)
+
+      helper.load_pipeline_status([project])
+      # Skip lazy loading of the `pipeline_status` attribute
+      pipeline_status = project.instance_variable_get('@pipeline_status')
+
+      expect(pipeline_status).to be_a(Gitlab::Cache::Ci::ProjectPipelineStatus)
+    end
+  end
+
   describe 'link_to_member' do
     let(:group)   { create(:group) }
     let(:project) { create(:empty_project, group: group) }

spec/lib/gitlab/cache/ci/project_pipeline_status_spec.rb

 require 'spec_helper'
 
-describe Gitlab::Cache::Ci::ProjectPipelineStatus do
+describe Gitlab::Cache::Ci::ProjectPipelineStatus, :redis do
   let(:project) { create(:project) }
   let(:pipeline_status) { described_class.new(project) }
+  let(:cache_key) { "projects/#{project.id}/pipeline_status" }
 
   describe '.load_for_project' do
     it "loads the status" do
@@ -12,12 +13,110 @@ describe Gitlab::Cache::Ci::ProjectPipelineStatus do
     end
   end
 
+  describe 'loading in batches' do
+    let(:status) { 'success' }
+    let(:sha) { '424d1b73bc0d3cb726eb7dc4ce17a4d48552f8c6' }
+    let(:ref) { 'master' }
+    let(:pipeline_info) { { sha: sha, status: status, ref: ref } }
+    let(:project_without_status) { create(:project) }
+
+    describe '.load_in_batch_for_projects' do
+      it 'preloads pipeline_status on projects' do
+        described_class.load_in_batch_for_projects([project])
+
+        # Don't call the accessor that would lazy load the variable
+        expect(project.instance_variable_get('@pipeline_status')).to be_a(described_class)
+      end
+
+      describe 'without a status in redis' do
+        it 'loads the status from a commit when it was not in redis' do
+          empty_status = { sha: nil, status: nil, ref: nil }
+          fake_pipeline = described_class.new(
+            project_without_status,
+            pipeline_info: empty_status,
+            loaded_from_cache: false
+          )
+
+          expect(described_class).to receive(:new).
+                                       with(project_without_status,
+                                            pipeline_info: empty_status,
+                                            loaded_from_cache: false).
+                                       and_return(fake_pipeline)
+          expect(fake_pipeline).to receive(:load_from_project)
+          expect(fake_pipeline).to receive(:store_in_cache)
+
+          described_class.load_in_batch_for_projects([project_without_status])
+        end
+
+        it 'only connects to redis twice' do
+          # Once to load, once to store in the cache
+          expect(Gitlab::Redis).to receive(:with).exactly(2).and_call_original
+
+          described_class.load_in_batch_for_projects([project_without_status])
+
+          expect(project_without_status.pipeline_status).not_to be_nil
+        end
+      end
+
+      describe 'when a status was cached in redis' do
+        before do
+          Gitlab::Redis.with do |redis|
+            redis.mapped_hmset(cache_key,
+                               { sha: sha, status: status, ref: ref })
+          end
+        end
+
+        it 'loads the correct status' do
+          described_class.load_in_batch_for_projects([project])
+
+          pipeline_status = project.instance_variable_get('@pipeline_status')
+
+          expect(pipeline_status.sha).to eq(sha)
+          expect(pipeline_status.status).to eq(status)
+          expect(pipeline_status.ref).to eq(ref)
+        end
+
+        it 'only connects to redis once' do
+          expect(Gitlab::Redis).to receive(:with).exactly(1).and_call_original
+
+          described_class.load_in_batch_for_projects([project])
+
+          expect(project.pipeline_status).not_to be_nil
+        end
+
+        it "doesn't load the status separatly" do
+          expect_any_instance_of(described_class).not_to receive(:load_from_project)
+          expect_any_instance_of(described_class).not_to receive(:load_from_cache)
+
+          described_class.load_in_batch_for_projects([project])
+        end
+      end
+    end
+
+    describe '.cached_results_for_projects' do
+      it 'loads a status from redis for all projects' do
+        Gitlab::Redis.with do |redis|
+          redis.mapped_hmset(cache_key, { sha: sha, status: status, ref: ref })
+        end
+
+        result = [{ loaded_from_cache: false, pipeline_info: { sha: nil, status: nil, ref: nil } },
+                  { loaded_from_cache: true, pipeline_info: pipeline_info }]
+
+        expect(described_class.cached_results_for_projects([project_without_status, project])).to eq(result)
+      end
+    end
+  end
+
   describe '.update_for_pipeline' do
     it 'refreshes the cache if nescessary' do
-      pipeline = build_stubbed(:ci_pipeline, sha: '123456', status: 'success')
+      pipeline = build_stubbed(:ci_pipeline,
+                               sha: '123456', status: 'success', ref: 'master')
       fake_status = double
       expect(described_class).to receive(:new).
-                                   with(pipeline.project, sha: '123456', status: 'success', ref: 'master').
+                                   with(pipeline.project,
+                                        pipeline_info: {
+                                          sha: '123456', status: 'success', ref: 'master'
+                                        }).
                                    and_return(fake_status)
 
       expect(fake_status).to receive(:store_in_cache_if_needed)
@@ -110,7 +209,7 @@ describe Gitlab::Cache::Ci::ProjectPipelineStatus do
       pipeline_status.status = 'failed'
 
       pipeline_status.store_in_cache
-      read_sha, read_status = Gitlab::Redis.with { |redis| redis.hmget("projects/#{project.id}/build_status", :sha, :status) }
+      read_sha, read_status = Gitlab::Redis.with { |redis| redis.hmget(cache_key, :sha, :status) }
 
       expect(read_sha).to eq('123456')
       expect(read_status).to eq('failed')
@@ -120,10 +219,10 @@ describe Gitlab::Cache::Ci::ProjectPipelineStatus do
   describe '#store_in_cache_if_needed', :redis do
     it 'stores the state in the cache when the sha is the HEAD of the project' do
       create(:ci_pipeline, :success, project: project, sha: project.commit.sha)
-      build_status = described_class.load_for_project(project)
+      pipeline_status = described_class.load_for_project(project)
 
-      build_status.store_in_cache_if_needed
-      sha, status, ref = Gitlab::Redis.with { |redis| redis.hmget("projects/#{project.id}/build_status", :sha, :status, :ref) }
+      pipeline_status.store_in_cache_if_needed
+      sha, status, ref = Gitlab::Redis.with { |redis| redis.hmget(cache_key, :sha, :status, :ref) }
 
       expect(sha).not_to be_nil
       expect(status).not_to be_nil
@@ -131,10 +230,13 @@ describe Gitlab::Cache::Ci::ProjectPipelineStatus do
     end
 
     it "doesn't store the status in redis when the sha is not the head of the project" do
-      other_status = described_class.new(project, sha: "123456", status: "failed")
+      other_status = described_class.new(
+        project,
+        pipeline_info: { sha: "123456", status: "failed" }
+      )
 
       other_status.store_in_cache_if_needed
-      sha, status = Gitlab::Redis.with { |redis| redis.hmget("projects/#{project.id}/build_status", :sha, :status) }
+      sha, status = Gitlab::Redis.with { |redis| redis.hmget(cache_key, :sha, :status) }
 
       expect(sha).to be_nil
       expect(status).to be_nil
@@ -142,11 +244,18 @@ describe Gitlab::Cache::Ci::ProjectPipelineStatus do
 
     it "deletes the cache if the repository doesn't have a head commit" do
       empty_project = create(:empty_project)
-      Gitlab::Redis.with { |redis| redis.mapped_hmset("projects/#{empty_project.id}/build_status", { sha: "sha", status: "pending", ref: 'master' }) }
-      other_status = described_class.new(empty_project, sha: "123456", status: "failed")
+      Gitlab::Redis.with do |redis|
+        redis.mapped_hmset(cache_key,
+                           { sha: 'sha', status: 'pending', ref: 'master' })
+      end
+
+      other_status = described_class.new(empty_project,
+                                         pipeline_info: {
+                                           sha: "123456", status: "failed"
+                                         })
 
       other_status.store_in_cache_if_needed
-      sha, status, ref = Gitlab::Redis.with { |redis| redis.hmget("projects/#{empty_project.id}/build_status", :sha, :status, :ref) }
+      sha, status, ref = Gitlab::Redis.with { |redis| redis.hmget("projects/#{empty_project.id}/pipeline_status", :sha, :status, :ref) }
 
       expect(sha).to be_nil
       expect(status).to be_nil
@@ -157,9 +266,13 @@ describe Gitlab::Cache::Ci::ProjectPipelineStatus do
   describe "with a status in redis", :redis do
     let(:status) { 'success' }
     let(:sha) { '424d1b73bc0d3cb726eb7dc4ce17a4d48552f8c6' }
+    let(:ref) { 'master' }
 
     before do
-      Gitlab::Redis.with { |redis| redis.mapped_hmset("projects/#{project.id}/build_status", { sha: sha, status: status }) }
+      Gitlab::Redis.with do |redis|
+        redis.mapped_hmset(cache_key,
+                           { sha: sha, status: status, ref: ref })
+      end
     end
 
     describe '#load_from_cache' do
@@ -168,6 +281,7 @@ describe Gitlab::Cache::Ci::ProjectPipelineStatus do
 
         expect(pipeline_status.sha).to eq(sha)
         expect(pipeline_status.status).to eq(status)
+        expect(pipeline_status.ref).to eq(ref)
       end
     end
 
@@ -181,7 +295,7 @@ describe Gitlab::Cache::Ci::ProjectPipelineStatus do
       it 'deletes values from redis'  do
         pipeline_status.delete_from_cache
 
-        key_exists = Gitlab::Redis.with { |redis| redis.exists("projects/#{project.id}/build_status") }
+        key_exists = Gitlab::Redis.with { |redis| redis.exists(cache_key) }
 
         expect(key_exists).to be_falsy
       end