Remove support for gitlab-metrics-exporter

This system was never in productive use and not
officially supported. We are retiring it now.

See https://gitlab.com/gitlab-org/gitlab-metrics-exporter/-/issues/31

lib/tasks/gitlab/metrics_exporter.rake

-# frozen_string_literal: true
-
-namespace :gitlab do
-  require_relative Rails.root.join('metrics_server', 'dependencies')
-  require_relative Rails.root.join('metrics_server', 'metrics_server')
-
-  namespace :metrics_exporter do
-    REPO = 'https://gitlab.com/gitlab-org/gitlab-metrics-exporter.git'
-
-    desc "GitLab | Metrics Exporter | Install or upgrade gitlab-metrics-exporter"
-    task :install, [:dir] => :gitlab_environment do |t, args|
-      unless args.dir.present?
-        abort %(Please specify the directory where you want to install the exporter
-Usage: rake "gitlab:metrics_exporter:install[/installation/dir]")
-      end
-
-      version = ENV['GITLAB_METRICS_EXPORTER_VERSION'] || MetricsServer.version
-      make = Gitlab::Utils.which('gmake') || Gitlab::Utils.which('make')
-
-      abort "Couldn't find a 'make' binary" unless make
-
-      checkout_or_clone_version(version: version, repo: REPO, target_dir: args.dir, clone_opts: %w[--depth 1])
-
-      Dir.chdir(args.dir) { run_command!([make]) }
-    end
-  end
-end

metrics_server/metrics_server.rb

@@ -7,10 +7,6 @@ class MetricsServer # rubocop:disable Gitlab/NamespacedClass
   PumaProcessSupervisor = Class.new(Gitlab::ProcessSupervisor)
 
   class << self
-    def version
-      Rails.root.join('GITLAB_METRICS_EXPORTER_VERSION').read.chomp
-    end
-
     def start_for_puma
       metrics_dir = ::Prometheus::Client.configuration.multiprocess_files_dir
 
@@ -28,45 +24,10 @@ def start_for_puma
     end
 
     def start_for_sidekiq(**options)
-      if new_metrics_server?
-        self.spawn('sidekiq', **options)
-      else
-        self.fork('sidekiq', **options)
-      end
-    end
-
-    def spawn(target, metrics_dir:, **options)
-      return spawn_ruby_server(target, metrics_dir: metrics_dir, **options) unless new_metrics_server?
-
-      settings = settings_value(target)
-      path = options[:path]&.then { |p| Pathname.new(p) } || Pathname.new('')
-      cmd = path.join('gitlab-metrics-exporter').to_path
-      env = {
-        'GOGC' => '10', # Set Go GC heap goal to 10% to curb memory growth.
-        'GME_MMAP_METRICS_DIR' => metrics_dir.to_s,
-        'GME_PROBES' => 'self,mmap,mmap_stats',
-        'GME_SERVER_HOST' => settings['address'],
-        'GME_SERVER_PORT' => settings['port'].to_s
-      }
-
-      if settings['log_enabled']
-        env['GME_LOG_FILE'] = File.join(Rails.root, 'log', "#{name(target)}.log")
-        env['GME_LOG_LEVEL'] = 'info'
-      else
-        env['GME_LOG_LEVEL'] = 'quiet'
-      end
-
-      if settings['tls_enabled']
-        env['GME_CERT_FILE'] = settings['tls_cert_path']
-        env['GME_CERT_KEY'] = settings['tls_key_path']
-      end
-
-      Process.spawn(env, cmd, err: $stderr, out: $stdout, pgroup: true).tap do |pid|
-        Process.detach(pid)
-      end
+      self.fork('sidekiq', **options)
     end
 
-    def spawn_ruby_server(target, metrics_dir:, wipe_metrics_dir: false, **options)
+    def spawn(target, metrics_dir:, wipe_metrics_dir: false)
       ensure_valid_target!(target)
 
       cmd = "#{Rails.root}/bin/metrics-server"
@@ -126,10 +87,6 @@ def settings_value(target)
       end
     end
 
-    def new_metrics_server?
-      Gitlab::Utils.to_boolean(ENV['GITLAB_GOLANG_METRICS_SERVER'])
-    end
-
     def ensure_valid_target!(target)
       raise "Target must be one of [puma,sidekiq]" unless %w(puma sidekiq).include?(target)
     end

qa/gdk/Dockerfile.gdk

@@ -88,13 +88,6 @@ RUN set -eux; \
     rm -rf ${GEM_HOME}/cache \
     && go clean -cache
 
-# Build metrics-exporter
-#
-COPY --chown=gdk:gdk GITLAB_METRICS_EXPORTER_VERSION ./gitlab/
-RUN set -eux; \
-    make gitlab-metrics-exporter-setup; \
-    go clean -cache
-
 # Install gitlab gem dependencies
 #
 COPY --chown=gdk:gdk Gemfile Gemfile.lock ./gitlab/

spec/commands/metrics_server/metrics_server_spec.rb

@@ -30,18 +30,6 @@
     }
   end
 
-  before(:all) do
-    Rake.application.rake_require 'tasks/gitlab/metrics_exporter'
-
-    @exporter_path = Rails.root.join('tmp', 'test', 'gme')
-
-    run_rake_task('gitlab:metrics_exporter:install', @exporter_path)
-  end
-
-  after(:all) do
-    FileUtils.rm_rf(@exporter_path)
-  end
-
   shared_examples 'serves metrics endpoint' do
     it 'serves /metrics endpoint' do
       start_server!
@@ -59,24 +47,18 @@
     end
   end
 
-  shared_examples 'spawns a server' do |target, use_golang_server|
-    context "targeting #{target} when using Golang server is #{use_golang_server}" do
+  shared_examples 'spawns a server' do |target|
+    context "targeting #{target}" do
       let(:metrics_dir) { Dir.mktmpdir }
 
       subject(:start_server!) do
-        @pid = MetricsServer.spawn(target, metrics_dir: metrics_dir, path: @exporter_path.join('bin'))
+        @pid = MetricsServer.spawn(target, metrics_dir: metrics_dir)
       end
 
       before do
-        if use_golang_server
-          stub_env('GITLAB_GOLANG_METRICS_SERVER', '1')
-          allow(Settings).to receive(:monitoring).and_return(
-            GitlabSettings::Options.build(config.dig('test', 'monitoring')))
-        else
-          config_file.write(YAML.dump(config))
-          config_file.close
-          stub_env('GITLAB_CONFIG', config_file.path)
-        end
+        config_file.write(YAML.dump(config))
+        config_file.close
+        stub_env('GITLAB_CONFIG', config_file.path)
         # We need to send a request to localhost
         WebMock.allow_net_connect!
       end
@@ -111,8 +93,6 @@
     end
   end
 
-  it_behaves_like 'spawns a server', 'puma', true
-  it_behaves_like 'spawns a server', 'puma', false
-  it_behaves_like 'spawns a server', 'sidekiq', true
-  it_behaves_like 'spawns a server', 'sidekiq', false
+  it_behaves_like 'spawns a server', 'puma'
+  it_behaves_like 'spawns a server', 'sidekiq'
 end

spec/metrics_server/metrics_server_spec.rb

@@ -69,136 +69,29 @@
       end
 
       describe '.spawn' do
-        context 'for legacy Ruby server' do
-          let(:expected_env) do
-            {
-              'METRICS_SERVER_TARGET' => target,
-              'WIPE_METRICS_DIR' => '0',
-              'GITLAB_CONFIG' => 'path/to/config/gitlab.yml'
-            }
-          end
-
-          before do
-            stub_env('GITLAB_CONFIG', 'path/to/config/gitlab.yml')
-          end
-
-          it 'spawns a new server process and returns its PID' do
-            expect(Process).to receive(:spawn).with(
-              expected_env,
-              end_with('bin/metrics-server'),
-              hash_including(pgroup: true)
-            ).and_return(99)
-            expect(Process).to receive(:detach).with(99)
-
-            pid = described_class.spawn(target, metrics_dir: metrics_dir)
-
-            expect(pid).to eq(99)
-          end
+        let(:expected_env) do
+          {
+            'METRICS_SERVER_TARGET' => target,
+            'WIPE_METRICS_DIR' => '0',
+            'GITLAB_CONFIG' => 'path/to/config/gitlab.yml'
+          }
         end
 
-        context 'for Golang server' do
-          let(:log_enabled) { false }
-          let(:settings) do
-            GitlabSettings::Options.build(
-              {
-                'web_exporter' => {
-                  'enabled' => true,
-                  'address' => 'localhost',
-                  'port' => '8083',
-                  'log_enabled' => log_enabled
-                },
-                'sidekiq_exporter' => {
-                  'enabled' => true,
-                  'address' => 'localhost',
-                  'port' => '8082',
-                  'log_enabled' => log_enabled
-                }
-              }
-            )
-          end
-
-          let(:expected_port) { target == 'puma' ? '8083' : '8082' }
-          let(:expected_env) do
-            {
-              'GOGC' => '10',
-              'GME_MMAP_METRICS_DIR' => metrics_dir,
-              'GME_PROBES' => 'self,mmap,mmap_stats',
-              'GME_SERVER_HOST' => 'localhost',
-              'GME_SERVER_PORT' => expected_port,
-              'GME_LOG_LEVEL' => 'quiet'
-            }
-          end
-
-          before do
-            stub_env('GITLAB_GOLANG_METRICS_SERVER', '1')
-            allow(::Settings).to receive(:monitoring).and_return(settings)
-          end
-
-          it 'spawns a new server process and returns its PID' do
-            expect(Process).to receive(:spawn).with(
-              expected_env,
-              'gitlab-metrics-exporter',
-              hash_including(pgroup: true)
-            ).and_return(99)
-            expect(Process).to receive(:detach).with(99)
-
-            pid = described_class.spawn(target, metrics_dir: metrics_dir)
-
-            expect(pid).to eq(99)
-          end
-
-          it 'can launch from explicit path instead of PATH' do
-            expect(Process).to receive(:spawn).with(
-              expected_env,
-              '/path/to/gme/gitlab-metrics-exporter',
-              hash_including(pgroup: true)
-            ).and_return(99)
-
-            described_class.spawn(target, metrics_dir: metrics_dir, path: '/path/to/gme/')
-          end
+        before do
+          stub_env('GITLAB_CONFIG', 'path/to/config/gitlab.yml')
+        end
 
-          context 'when logs are enabled' do
-            let(:log_enabled) { true }
-            let(:expected_log_file) { target == 'puma' ? 'web_exporter.log' : 'sidekiq_exporter.log' }
-
-            it 'sets log related environment variables' do
-              expect(Process).to receive(:spawn).with(
-                expected_env.merge(
-                  'GME_LOG_LEVEL' => 'info',
-                  'GME_LOG_FILE' => File.join(Rails.root, 'log', expected_log_file)
-                ),
-                'gitlab-metrics-exporter',
-                hash_including(pgroup: true)
-              ).and_return(99)
-
-              described_class.spawn(target, metrics_dir: metrics_dir)
-            end
-          end
+        it 'spawns a new server process and returns its PID' do
+          expect(Process).to receive(:spawn).with(
+            expected_env,
+            end_with('bin/metrics-server'),
+            hash_including(pgroup: true)
+          ).and_return(99)
+          expect(Process).to receive(:detach).with(99)
 
-          context 'when TLS settings are present' do
-            before do
-              settings.web_exporter['tls_enabled'] = true
-              settings.web_exporter['tls_cert_path'] = '/path/to/cert.pem'
-              settings.web_exporter['tls_key_path'] = '/path/to/key.pem'
+          pid = described_class.spawn(target, metrics_dir: metrics_dir)
 
-              settings.sidekiq_exporter['tls_enabled'] = true
-              settings.sidekiq_exporter['tls_cert_path'] = '/path/to/cert.pem'
-              settings.sidekiq_exporter['tls_key_path'] = '/path/to/key.pem'
-            end
-
-            it 'sets the correct environment variables' do
-              expect(Process).to receive(:spawn).with(
-                expected_env.merge(
-                  'GME_CERT_FILE' => '/path/to/cert.pem',
-                  'GME_CERT_KEY' => '/path/to/key.pem'
-                ),
-                '/path/to/gme/gitlab-metrics-exporter',
-                hash_including(pgroup: true)
-              ).and_return(99)
-
-              described_class.spawn(target, metrics_dir: metrics_dir, path: '/path/to/gme/')
-            end
-          end
+          expect(pid).to eq(99)
         end
       end
     end
@@ -214,21 +107,10 @@
     end
 
     describe '.spawn' do
-      context 'for legacy Ruby server' do
-        it 'raises an error' do
-          expect { described_class.spawn('unsupported', metrics_dir: metrics_dir) }.to(
-            raise_error('Target must be one of [puma,sidekiq]')
-          )
-        end
-      end
-
-      context 'for Golang server' do
-        it 'raises an error' do
-          stub_env('GITLAB_GOLANG_METRICS_SERVER', '1')
-          expect { described_class.spawn('unsupported', metrics_dir: metrics_dir) }.to(
-            raise_error('Target must be one of [puma,sidekiq]')
-          )
-        end
+      it 'raises an error' do
+        expect { described_class.spawn('unsupported', metrics_dir: metrics_dir) }.to(
+          raise_error('Target must be one of [puma,sidekiq]')
+        )
       end
     end
   end
@@ -345,21 +227,10 @@
   end
 
   describe '.start_for_sidekiq' do
-    context 'for legacy Ruby server' do
-      it 'forks the parent process' do
-        expect(Process).to receive(:fork).and_return(42)
+    it 'forks the parent process' do
+      expect(Process).to receive(:fork).and_return(42)
 
-        described_class.start_for_sidekiq(metrics_dir: '/path/to/metrics')
-      end
-    end
-
-    context 'for Golang server' do
-      it 'spawns the server process' do
-        stub_env('GITLAB_GOLANG_METRICS_SERVER', '1')
-        expect(Process).to receive(:spawn).and_return(42)
-
-        described_class.start_for_sidekiq(metrics_dir: '/path/to/metrics')
-      end
+      described_class.start_for_sidekiq(metrics_dir: '/path/to/metrics')
     end
   end
 

spec/tasks/gitlab/metrics_exporter_rake_spec.rb

-# frozen_string_literal: true
-
-require 'rake_helper'
-require_relative '../../support/helpers/next_instance_of'
-
-RSpec.describe 'gitlab:metrics_exporter:install', feature_category: :metrics do
-  before do
-    Rake.application.rake_require 'tasks/gitlab/metrics_exporter'
-  end
-
-  subject(:task) do
-    Rake::Task['gitlab:metrics_exporter:install']
-  end
-
-  context 'when no target directory is specified' do
-    it 'aborts with an error message' do
-      expect do
-        expect { task.execute }.to output(/Please specify the directory/).to_stdout
-      end.to raise_error(SystemExit)
-    end
-  end
-
-  context 'when target directory is specified' do
-    let(:args) { Rake::TaskArguments.new(%w[dir], %w[path/to/exporter]) }
-    let(:context) { TOPLEVEL_BINDING.eval('self') }
-    let(:expected_clone_params) do
-      {
-        repo: 'https://gitlab.com/gitlab-org/gitlab-metrics-exporter.git',
-        version: an_instance_of(String),
-        target_dir: 'path/to/exporter'
-      }
-    end
-
-    context 'when dependencies are missing' do
-      it 'aborts with an error message' do
-        expect(Gitlab::Utils).to receive(:which).with('gmake').ordered
-        expect(Gitlab::Utils).to receive(:which).with('make').ordered
-
-        expect do
-          expect { task.execute(args) }.to output(/Couldn't find a 'make' binary/).to_stdout
-        end.to raise_error(SystemExit)
-      end
-    end
-
-    it 'installs the exporter with gmake' do
-      expect(Gitlab::Utils).to receive(:which).with('gmake').and_return('path/to/gmake').ordered
-      expect(context).to receive(:checkout_or_clone_version).with(hash_including(expected_clone_params)).ordered
-      expect(Dir).to receive(:chdir).with('path/to/exporter').and_yield.ordered
-      expect(context).to receive(:run_command!).with(['path/to/gmake']).ordered
-
-      task.execute(args)
-    end
-
-    it 'installs the exporter with make' do
-      expect(Gitlab::Utils).to receive(:which).with('gmake').ordered
-      expect(Gitlab::Utils).to receive(:which).with('make').and_return('path/to/make').ordered
-      expect(context).to receive(:checkout_or_clone_version).with(hash_including(expected_clone_params)).ordered
-      expect(Dir).to receive(:chdir).with('path/to/exporter').and_yield.ordered
-      expect(context).to receive(:run_command!).with(['path/to/make']).ordered
-
-      task.execute(args)
-    end
-
-    context 'when overriding version via environment variable' do
-      before do
-        stub_env('GITLAB_METRICS_EXPORTER_VERSION', '1.0')
-      end
-
-      it 'clones from repository with that version instead' do
-        expect(Gitlab::Utils).to receive(:which).with('gmake').and_return('path/to/gmake').ordered
-        expect(context).to receive(:checkout_or_clone_version).with(
-          hash_including(expected_clone_params.merge(version: '1.0'))
-        ).ordered
-        expect(Dir).to receive(:chdir).with('path/to/exporter').and_yield.ordered
-        expect(context).to receive(:run_command!).with(['path/to/gmake']).ordered
-
-        task.execute(args)
-      end
-    end
-  end
-end