Split the metrics implementation to separate modules for Influx and Prometheus

2 files changed, 204 insertions, 0 deletions

diff --git a/lib/gitlab/metrics/influx_db.rb b/lib/gitlab/metrics/influx_db.rb
new file mode 100644
index 00000000000..c5d7a2b56b9
--- /dev/null
+++ b/lib/gitlab/metrics/influx_db.rb
@@ -0,0 +1,163 @@
+module Gitlab
+  module Metrics
+    module InfluxDb
+      include Gitlab::CurrentSettings
+
+      def influx_metrics_enabled?
+        settings[:enabled] || false
+      end
+
+      RAILS_ROOT = Rails.root.to_s
+      METRICS_ROOT = Rails.root.join('lib', 'gitlab', 'metrics').to_s
+      PATH_REGEX = /^#{RAILS_ROOT}\/?/
+
+      def settings
+        @settings ||= {
+          enabled: current_application_settings[:metrics_enabled],
+          pool_size: current_application_settings[:metrics_pool_size],
+          timeout: current_application_settings[:metrics_timeout],
+          method_call_threshold: current_application_settings[:metrics_method_call_threshold],
+          host: current_application_settings[:metrics_host],
+          port: current_application_settings[:metrics_port],
+          sample_interval: current_application_settings[:metrics_sample_interval] || 15,
+          packet_size: current_application_settings[:metrics_packet_size] || 1
+        }
+      end
+
+      def mri?
+        RUBY_ENGINE == 'ruby'
+      end
+
+      def method_call_threshold
+        # This is memoized since this method is called for every instrumented
+        # method. Loading data from an external cache on every method call slows
+        # things down too much.
+        @method_call_threshold ||= settings[:method_call_threshold]
+      end
+
+      def pool
+        @pool
+      end
+
+      def submit_metrics(metrics)
+        prepared = prepare_metrics(metrics)
+
+        pool&.with do |connection|
+          prepared.each_slice(settings[:packet_size]) do |slice|
+            begin
+              connection.write_points(slice)
+            rescue StandardError
+            end
+          end
+        end
+      rescue Errno::EADDRNOTAVAIL, SocketError => ex
+        Gitlab::EnvironmentLogger.error('Cannot resolve InfluxDB address. GitLab Performance Monitoring will not work.')
+        Gitlab::EnvironmentLogger.error(ex)
+      end
+
+      def prepare_metrics(metrics)
+        metrics.map do |hash|
+          new_hash = hash.symbolize_keys
+
+          new_hash[:tags].each do |key, value|
+            if value.blank?
+              new_hash[:tags].delete(key)
+            else
+              new_hash[:tags][key] = escape_value(value)
+            end
+          end
+
+          new_hash
+        end
+      end
+
+      def escape_value(value)
+        value.to_s.gsub('=', '\\=')
+      end
+
+      # Measures the execution time of a block.
+      #
+      # Example:
+      #
+      #     Gitlab::Metrics.measure(:find_by_username_duration) do
+      #       User.find_by_username(some_username)
+      #     end
+      #
+      # name - The name of the field to store the execution time in.
+      #
+      # Returns the value yielded by the supplied block.
+      def measure(name)
+        trans = current_transaction
+
+        return yield unless trans
+
+        real_start = Time.now.to_f
+        cpu_start = System.cpu_time
+
+        retval = yield
+
+        cpu_stop = System.cpu_time
+        real_stop = Time.now.to_f
+
+        real_time = (real_stop - real_start) * 1000.0
+        cpu_time = cpu_stop - cpu_start
+
+        trans.increment("#{name}_real_time", real_time)
+        trans.increment("#{name}_cpu_time", cpu_time)
+        trans.increment("#{name}_call_count", 1)
+
+        retval
+      end
+
+      # Adds a tag to the current transaction (if any)
+      #
+      # name - The name of the tag to add.
+      # value - The value of the tag.
+      def tag_transaction(name, value)
+        trans = current_transaction
+
+        trans&.add_tag(name, value)
+      end
+
+      # Sets the action of the current transaction (if any)
+      #
+      # action - The name of the action.
+      def action=(action)
+        trans = current_transaction
+
+        trans&.action = action
+      end
+
+      # Tracks an event.
+      #
+      # See `Gitlab::Metrics::Transaction#add_event` for more details.
+      def add_event(*args)
+        trans = current_transaction
+
+        trans&.add_event(*args)
+      end
+
+      # Returns the prefix to use for the name of a series.
+      def series_prefix
+        @series_prefix ||= Sidekiq.server? ? 'sidekiq_' : 'rails_'
+      end
+
+      # Allow access from other metrics related middlewares
+      def current_transaction 
+        Transaction.current
+      end
+
+      # When enabled this should be set before being used as the usual pattern
+      # "@foo ||= bar" is _not_ thread-safe.
+      if influx_metrics_enabled?
+        @pool = ConnectionPool.new(size: settings[:pool_size], timeout: settings[:timeout]) do
+          host = settings[:host]
+          port = settings[:port]
+
+          InfluxDB::Client.
+            new(udp: { host: host, port: port })
+        end
+      end
+    end
+  end
+end
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diff --git a/lib/gitlab/metrics/prometheus.rb b/lib/gitlab/metrics/prometheus.rb
new file mode 100644
index 00000000000..493da4d779c
--- /dev/null
+++ b/lib/gitlab/metrics/prometheus.rb
@@ -0,0 +1,41 @@
+require 'prometheus/client'
+
+module Gitlab
+  module Metrics
+    module Prometheus
+      include Gitlab::CurrentSettings
+
+      def prometheus_metrics_enabled?
+        @prometheus_metrics_enabled ||= current_application_settings[:prometheus_metrics_enabled] || false
+      end
+
+      def registry
+        @registry ||= ::Prometheus::Client.registry
+      end
+
+      def counter(name, docstring, base_labels = {})
+        provide_metric(name) || registry.counter(name, docstring, base_labels)
+      end
+
+      def summary(name, docstring, base_labels = {})
+        provide_metric(name) || registry.summary(name, docstring, base_labels)
+      end
+
+      def gauge(name, docstring, base_labels = {})
+        provide_metric(name) || registry.gauge(name, docstring, base_labels)
+      end
+
+      def histogram(name, docstring, base_labels = {}, buckets = ::Prometheus::Client::Histogram::DEFAULT_BUCKETS)
+        provide_metric(name) || registry.histogram(name, docstring, base_labels, buckets)
+      end
+
+      def provide_metric(name)
+        if prometheus_metrics_enabled?
+          registry.get(name)
+        else
+          NullMetric.new
+        end
+      end
+    end
+  end
+end
\ No newline at end of file