Add latest changes from gitlab-org/gitlab@master

4 files changed, 37 insertions, 1 deletions

diff --git a/metrics_server/dependencies.rb b/metrics_server/dependencies.rb
index a459efef1ad..494b795b292 100644
--- a/metrics_server/dependencies.rb
+++ b/metrics_server/dependencies.rb
@@ -6,6 +6,7 @@ require 'fileutils'
 
 require 'active_support/concern'
 require 'active_support/inflector'
+require 'active_support/core_ext/numeric/bytes'
 
 require 'prometheus/client'
 require 'rack'
@@ -18,6 +19,9 @@ require_relative '../lib/gitlab/utils/strong_memoize'
 require_relative '../lib/prometheus/cleanup_multiproc_dir_service'
 require_relative '../lib/gitlab/metrics/prometheus'
 require_relative '../lib/gitlab/metrics'
+require_relative '../lib/gitlab/metrics/system'
+require_relative '../lib/gitlab/metrics/samplers/base_sampler'
+require_relative '../lib/gitlab/metrics/samplers/ruby_sampler'
 require_relative '../lib/gitlab/metrics/exporter/base_exporter'
 require_relative '../lib/gitlab/metrics/exporter/sidekiq_exporter'
 require_relative '../lib/gitlab/health_checks/probes/collection'
diff --git a/metrics_server/metrics_server.rb b/metrics_server/metrics_server.rb
index 56fc20dcc9d..33b31326d2a 100644
--- a/metrics_server/metrics_server.rb
+++ b/metrics_server/metrics_server.rb
@@ -40,14 +40,20 @@ class MetricsServer # rubocop:disable Gitlab/NamespacedClass
   def start
     ::Prometheus::Client.configure do |config|
       config.multiprocess_files_dir = @metrics_dir
+      config.pid_provider = proc { "#{@target}_exporter" }
     end
 
     FileUtils.mkdir_p(@metrics_dir, mode: 0700)
     ::Prometheus::CleanupMultiprocDirService.new.execute if @wipe_metrics_dir
 
-    settings = Settings.new(Settings.monitoring[name])
+    # We need to `warmup: true` since otherwise the sampler and exporter threads enter
+    # a race where not all Prometheus db files will be visible to the exporter, resulting
+    # in missing metrics.
+    # Warming up ensures that these files exist prior to the exporter starting up.
+    Gitlab::Metrics::Samplers::RubySampler.initialize_instance(warmup: true).start
 
     exporter_class = "Gitlab::Metrics::Exporter::#{@target.camelize}Exporter".constantize
+    settings = Settings.new(Settings.monitoring[name])
     server = exporter_class.instance(settings, synchronous: true)
 
     server.start
diff --git a/metrics_server/override_gitlab_current_settings.rb b/metrics_server/override_gitlab_current_settings.rb
new file mode 100644
index 00000000000..1dc19b5da23
--- /dev/null
+++ b/metrics_server/override_gitlab_current_settings.rb
@@ -0,0 +1,21 @@
+# rubocop:disable Naming/FileName
+# frozen_string_literal: true
+
+# We need to supply this outside of Rails because:
+# RubySampler needs Gitlab::Metrics needs Gitlab::Metrics::Prometheus needs Gitlab::CurrentSettings needs ::Settings
+# to check for `prometheus_metrics_enabled`. We therefore simply redirect it to our own Settings type.
+module Gitlab
+  module CurrentSettings
+    class << self
+      def prometheus_metrics_enabled
+        # We make the simplified assumption that when the metrics-server runs,
+        # Prometheus metrics are enabled. Since the latter is a setting stored
+        # in the application database, we have no access to it here, so we need
+        # to hard-code it.
+        true
+      end
+    end
+  end
+end
+
+# rubocop:enable Naming/FileName
diff --git a/metrics_server/settings_overrides.rb b/metrics_server/settings_overrides.rb
index 8572b4f86b0..b3fd39229d5 100644
--- a/metrics_server/settings_overrides.rb
+++ b/metrics_server/settings_overrides.rb
@@ -9,6 +9,11 @@
 # Here we make the necessary constants available conditionally.
 require_relative 'override_rails_constants' unless Object.const_defined?('Rails')
 
+# We need to supply this outside of Rails because:
+# RubySampler needs Gitlab::Metrics needs Gitlab::Metrics::Prometheus needs Gitlab::CurrentSettings needs ::Settings
+# to check for `prometheus_metrics_enabled`. We therefore simply redirect it to our own Settings type.
+require_relative 'override_gitlab_current_settings' unless Object.const_defined?('Gitlab::CurrentSettings')
+
 require_relative '../config/settings'
 
 # rubocop:enable Naming/FileName