1 files changed, 103 insertions, 0 deletions
diff --git a/lib/gitlab/ci/pipeline/logger.rb b/lib/gitlab/ci/pipeline/logger.rb
new file mode 100644
index 00000000000..97f7dddd09a
--- /dev/null
+++ b/lib/gitlab/ci/pipeline/logger.rb
@@ -0,0 +1,103 @@
+# frozen_string_literal: true
+
+module Gitlab
+  module Ci
+    module Pipeline
+      class Logger
+        include ::Gitlab::Utils::StrongMemoize
+
+        def self.current_monotonic_time
+          ::Gitlab::Metrics::System.monotonic_time
+        end
+
+        def initialize(project:, destination: Gitlab::AppJsonLogger)
+          @started_at = current_monotonic_time
+          @project = project
+          @destination = destination
+          @log_conditions = []
+
+          yield(self) if block_given?
+        end
+
+        def log_when(&block)
+          log_conditions.push(block)
+        end
+
+        def instrument(operation)
+          return yield unless enabled?
+
+          raise ArgumentError, 'block not given' unless block_given?
+
+          op_started_at = current_monotonic_time
+
+          result = yield
+
+          observe("#{operation}_duration_s", current_monotonic_time - op_started_at)
+
+          result
+        end
+
+        def observe(operation, value)
+          return unless enabled?
+
+          observations[operation.to_s].push(value)
+        end
+
+        def commit(pipeline:, caller:)
+          return unless log?
+
+          attributes = {
+            class: self.class.name.to_s,
+            pipeline_creation_caller: caller,
+            project_id: project.id,
+            pipeline_id: pipeline.id,
+            pipeline_persisted: pipeline.persisted?,
+            pipeline_source: pipeline.source,
+            pipeline_creation_service_duration_s: age
+          }.stringify_keys.merge(observations_hash)
+
+          destination.info(attributes)
+        end
+
+        def observations_hash
+          observations.transform_values do |values|
+            next if values.empty?
+
+            {
+              'count' => values.size,
+              'min' => values.min,
+              'max' => values.max,
+              'avg' => values.sum / values.size
+            }
+          end.compact
+        end
+
+        private
+
+        attr_reader :project, :destination, :started_at, :log_conditions
+        delegate :current_monotonic_time, to: :class
+
+        def age
+          current_monotonic_time - started_at
+        end
+
+        def log?
+          return false unless enabled?
+          return true if log_conditions.empty?
+
+          log_conditions.any? { |cond| cond.call(observations) }
+        end
+
+        def enabled?
+          strong_memoize(:enabled) do
+            ::Feature.enabled?(:ci_pipeline_creation_logger, project, type: :ops, default_enabled: :yaml)
+          end
+        end
+
+        def observations
+          @observations ||= Hash.new { |hash, key| hash[key] = [] }
+        end
+      end
+    end
+  end
+end