Include Puma worker PID in structured log

Changelog: other

doc/administration/logs.md

@@ -97,7 +97,8 @@ Line breaks were added to examples for legibility:
   "cpu_s":17.50,
   "db_duration_s":0.08,
   "view_duration_s":2.39,
-  "duration_s":20.54
+  "duration_s":20.54,
+  "pid": 81836
 }
 ```
 
@@ -120,6 +121,7 @@ seconds:
 - `redis_<instance>_duration_s`: Total time to retrieve data from a Redis instance
 - `redis_<instance>_read_bytes`: Total bytes read from a Redis instance
 - `redis_<instance>_write_bytes`: Total bytes written to a Redis instance
+- `pid`: Process ID of the Puma worker
 
 User clone and fetch activity using HTTP transport appears in the log as `action: git_upload_pack`.
 
@@ -190,7 +192,8 @@ Starting with GitLab 12.5, if an error occurs, an
   "cpu_s":17.50,
   "db_duration_s":0.08,
   "view_duration_s":2.39,
-  "duration_s":20.54
+  "duration_s":20.54,
+  "pid": 81836,
   "exception.class": "NameError",
   "exception.message": "undefined local variable or method `adsf' for #<Admin::DashboardController:0x00007ff3c9648588>",
   "exception.backtrace": [

lib/gitlab/instrumentation_helper.rb

@@ -30,6 +30,7 @@ module Gitlab
       instrument_cpu(payload)
       instrument_thread_memory_allocations(payload)
       instrument_load_balancing(payload)
+      instrument_pid(payload)
     end
 
     def instrument_gitaly(payload)
@@ -99,6 +100,10 @@ module Gitlab
       payload[:cpu_s] = cpu_s.round(DURATION_PRECISION) if cpu_s
     end
 
+    def instrument_pid(payload)
+      payload[:pid] = Process.pid
+    end
+
     def instrument_thread_memory_allocations(payload)
       counters = ::Gitlab::Memory::Instrumentation.measure_thread_memory_allocations(
         ::Gitlab::RequestContext.instance.thread_memory_allocations)

spec/lib/gitlab/grape_logging/loggers/perf_logger_spec.rb

@@ -3,26 +3,23 @@
 require 'spec_helper'
 
 RSpec.describe Gitlab::GrapeLogging::Loggers::PerfLogger do
-  subject { described_class.new }
+  let(:mock_request) { OpenStruct.new(env: {}) }
 
   describe ".parameters" do
-    let(:mock_request) { OpenStruct.new(env: {}) }
+    subject { described_class.new.parameters(mock_request, nil) }
 
-    describe 'when no performance datais are present' do
-      it 'returns an empty Hash' do
-        expect(subject.parameters(mock_request, nil)).to eq({})
-      end
+    let(:perf_data) { { redis_calls: 1 } }
+
+    describe 'when no performance data present' do
+      it { is_expected.not_to include(perf_data) }
     end
 
-    describe 'when Redis calls are present', :request_store do
-      it 'returns a Hash with Redis information' do
+    describe 'when performance data present', :request_store do
+      before do
         Gitlab::Redis::SharedState.with { |redis| redis.get('perf-logger-test') }
-
-        payload = subject.parameters(mock_request, nil)
-
-        expect(payload[:redis_calls]).to eq(1)
-        expect(payload[:redis_duration_s]).to be >= 0
       end
+
+      it { is_expected.to include(perf_data) }
     end
   end
 end

spec/lib/gitlab/instrumentation_helper_spec.rb

@@ -83,6 +83,12 @@ RSpec.describe Gitlab::InstrumentationHelper do
       expect(payload).to include(:cpu_s)
     end
 
+    it 'logs the process ID' do
+      subject
+
+      expect(payload).to include(:pid)
+    end
+
     context 'when logging memory allocations' do
       include MemoryInstrumentationHelper