Commit 1e607c26 authored by Balakumar's avatar Balakumar Committed by Mayra Cabrera

Marginalia with feature check on app start

parent ad72bab6
......@@ -22,6 +22,7 @@ gem 'rugged', '~> 0.28'
gem 'grape-path-helpers', '~> 1.1'
gem 'faraday', '~> 0.12'
gem 'marginalia', '~> 1.8.0'
# Authentication libraries
gem 'devise', '~> 4.6'
......
......@@ -596,6 +596,9 @@ GEM
mail_room (0.9.1)
marcel (0.3.3)
mimemagic (~> 0.3.2)
marginalia (1.8.0)
actionpack (>= 2.3)
activerecord (>= 2.3)
memoist (0.16.0)
memoizable (0.4.2)
thread_safe (~> 0.3, >= 0.3.1)
......@@ -1245,6 +1248,7 @@ DEPENDENCIES
lograge (~> 0.5)
loofah (~> 2.2)
mail_room (~> 0.9.1)
marginalia (~> 1.8.0)
memory_profiler (~> 0.9)
method_source (~> 0.8)
mimemagic (~> 0.3.2)
......
# frozen_string_literal: true
require 'marginalia'
::Marginalia::Comment.extend(::Gitlab::Marginalia::Comment)
# Patch to modify 'Marginalia::ActiveRecordInstrumentation.annotate_sql' method with feature check.
# Orignal Marginalia::ActiveRecordInstrumentation is included to ActiveRecord::ConnectionAdapters::PostgreSQLAdapter in the Marginalia Railtie.
# Refer: https://github.com/basecamp/marginalia/blob/v1.8.0/lib/marginalia/railtie.rb#L67
ActiveRecord::ConnectionAdapters::PostgreSQLAdapter.prepend(Gitlab::Marginalia::ActiveRecordInstrumentation)
Marginalia::Comment.components = [:application, :controller, :action, :correlation_id, :jid, :job_class, :line]
Gitlab::Marginalia.set_application_name
Gitlab::Marginalia.enable_sidekiq_instrumentation
Gitlab::Marginalia.set_feature_cache
......@@ -103,6 +103,10 @@ description: 'Learn how to contribute to GitLab.'
- [Swapping tables](swapping_tables.md)
- [Deleting migrations](deleting_migrations.md)
### Debugging
- Tracing the source of an SQL query using query comments with [Marginalia](database_query_comments.md)
### Best practices
- [Merge Request checklist](database_merge_request_checklist.md)
......
# Database query comments with Marginalia
The [Marginalia gem](https://github.com/basecamp/marginalia) is used to add
query comments containing application related context information to PostgreSQL
queries generated by ActiveRecord.
It is very useful for tracing problematic queries back to the application source.
A DB Engineer during an on-call incident will have the full context of a query
and its application source from the comments.
## Metadata information in comments
Queries generated from **Rails** include the following metadata in comments:
- `application`
- `controller`
- `action`
- `correlation_id`
- `line`
Queries generated from **Sidekiq** workers will include the following metadata
in comments:
- `application`
- `jid`
- `job_class`
- `correlation_id`
- `line`
Examples of queries with comments as observed in `development.log`:
1. Rails:
```sql
SELECT "project_features".* FROM "project_features" WHERE "project_features"."project_id" = $1 LIMIT $2 [["project_id", 5], ["LIMIT", 1]] /*application:web,controller:jobs,action:trace,correlation_id:rYF4mey9CH3,line:/app/policies/project_policy.rb:504:in `feature_available?'*/
```
1. Sidekiq:
```sql
SELECT "ci_pipelines".* FROM "ci_pipelines" WHERE "ci_pipelines"."id" = $1 LIMIT $2 [["id", 64], ["LIMIT", 1]] /*application:sidekiq,jid:e7d6668a39a991e323009833,job_class:ExpireJobCacheWorker,correlation_id:rYF4mey9CH3,line:/app/workers/expire_job_cache_worker.rb:14:in `perform'*/
```
## Enable/Disable the feature
Enabling or disabling the feature requires a **restart/SIGHUP** of the Web and
Sidekiq workers, as the feature flag's state is memoized upon starting up.
The `feature_flag` for this feature is **disabled** by default. You can enable
or disable it with:
```ruby
Feature.enable(:marginalia)
Feature.disable(:marginalia)
```
---
title: Added Marginalia feature which can generate PostgreSQL query comments to Gitlab
merge_request: 21364
author: BalaKumar
type: added
# frozen_string_literal: true
module Gitlab
module Marginalia
MARGINALIA_FEATURE_FLAG = :marginalia
def self.set_application_name
::Marginalia.application_name = Gitlab.process_name
end
def self.enable_sidekiq_instrumentation
if Sidekiq.server?
::Marginalia::SidekiqInstrumentation.enable!
end
end
def self.cached_feature_enabled?
!!@enabled
end
def self.set_feature_cache
# During db:create and db:bootstrap skip feature query as DB is not available yet.
return false unless ActiveRecord::Base.connected? && Gitlab::Database.cached_table_exists?('features')
@enabled = Feature.enabled?(MARGINALIA_FEATURE_FLAG)
end
end
end
# frozen_string_literal: true
# Patch to annotate sql only when the feature is enabled.
module Gitlab
module Marginalia
module ActiveRecordInstrumentation
def annotate_sql(sql)
Gitlab::Marginalia.cached_feature_enabled? ? super(sql) : sql
end
end
end
end
# frozen_string_literal: true
# Module to support correlation_id and additional job details.
module Gitlab
module Marginalia
module Comment
private
def jid
bg_job["jid"] if bg_job.present?
end
def job_class
bg_job["class"] if bg_job.present?
end
def correlation_id
if bg_job.present?
bg_job["correlation_id"]
else
Labkit::Correlation::CorrelationId.current_id
end
end
def bg_job
job = ::Marginalia::Comment.marginalia_job
# We are using 'Marginalia::SidekiqInstrumentation' which does not support 'ActiveJob::Base'.
# Gitlab also uses 'ActionMailer::DeliveryJob' which inherits from ActiveJob::Base.
# So below condition is used to return metadata for such jobs.
if job && job.is_a?(ActionMailer::DeliveryJob)
{
"class" => job.arguments.first,
"jid" => job.job_id
}
else
job
end
end
end
end
end
# frozen_string_literal: true
require 'spec_helper'
describe 'Marginalia spec' do
class MarginaliaTestController < ActionController::Base
def first_user
User.first
render body: nil
end
end
class MarginaliaTestJob
include Sidekiq::Worker
def perform
User.first
end
end
class MarginaliaTestMailer < BaseMailer
def first_user
User.first
end
end
def add_sidekiq_middleware
# Reference: https://github.com/mperham/sidekiq/wiki/Testing#testing-server-middlewaresidekiq
# Sidekiq test harness fakes worker without its server middlewares, so include instrumentation to 'Sidekiq::Testing' server middleware.
Sidekiq::Testing.server_middleware do |chain|
chain.add Marginalia::SidekiqInstrumentation::Middleware
end
end
def remove_sidekiq_middleware
Sidekiq::Testing.server_middleware do |chain|
chain.remove Marginalia::SidekiqInstrumentation::Middleware
end
end
def stub_feature(value)
allow(Gitlab::Marginalia).to receive(:cached_feature_enabled?).and_return(value)
end
def make_request(correlation_id)
request_env = Rack::MockRequest.env_for('/')
::Labkit::Correlation::CorrelationId.use_id(correlation_id) do
MarginaliaTestController.action(:first_user).call(request_env)
end
end
describe 'For rails web requests' do
let(:correlation_id) { SecureRandom.uuid }
let(:recorded) { ActiveRecord::QueryRecorder.new { make_request(correlation_id) } }
let(:component_map) do
{
"application" => "test",
"controller" => "marginalia_test",
"action" => "first_user",
"line" => "/spec/support/helpers/query_recorder.rb",
"correlation_id" => correlation_id
}
end
context 'when the feature is enabled' do
before do
stub_feature(true)
end
it 'generates a query that includes the component and value' do
component_map.each do |component, value|
expect(recorded.log.last).to include("#{component}:#{value}")
end
end
end
context 'when the feature is disabled' do
before do
stub_feature(false)
end
it 'excludes annotations in generated queries' do
expect(recorded.log.last).not_to include("/*")
expect(recorded.log.last).not_to include("*/")
end
end
end
describe 'for Sidekiq worker jobs' do
before(:all) do
add_sidekiq_middleware
# Because of faking, 'Sidekiq.server?' does not work so implicitly set application name which is done in config/initializers/0_marginalia.rb
Marginalia.application_name = "sidekiq"
end
after(:all) do
MarginaliaTestJob.clear
remove_sidekiq_middleware
end
around do |example|
Sidekiq::Testing.fake! { example.run }
end
before do
MarginaliaTestJob.perform_async
end
let(:sidekiq_job) { MarginaliaTestJob.jobs.first }
let(:recorded) { ActiveRecord::QueryRecorder.new { MarginaliaTestJob.drain } }
let(:component_map) do
{
"application" => "sidekiq",
"job_class" => "MarginaliaTestJob",
"line" => "/spec/support/sidekiq_middleware.rb",
"correlation_id" => sidekiq_job['correlation_id'],
"jid" => sidekiq_job['jid']
}
end
context 'when the feature is enabled' do
before do
stub_feature(true)
end
it 'generates a query that includes the component and value' do
component_map.each do |component, value|
expect(recorded.log.last).to include("#{component}:#{value}")
end
end
describe 'for ActionMailer delivery jobs' do
let(:delivery_job) { MarginaliaTestMailer.first_user.deliver_later }
let(:recorded) do
ActiveRecord::QueryRecorder.new do
delivery_job.perform_now
end
end
let(:component_map) do
{
"application" => "sidekiq",
"line" => "/lib/gitlab/i18n.rb",
"jid" => delivery_job.job_id,
"job_class" => delivery_job.arguments.first
}
end
it 'generates a query that includes the component and value' do
component_map.each do |component, value|
expect(recorded.log.last).to include("#{component}:#{value}")
end
end
end
end
context 'when the feature is disabled' do
before do
stub_feature(false)
end
it 'excludes annotations in generated queries' do
expect(recorded.log.last).not_to include("/*")
expect(recorded.log.last).not_to include("*/")
end
end
end
end
......@@ -130,10 +130,10 @@ describe PipelineSerializer do
it 'preloads related merge requests' do
recorded = ActiveRecord::QueryRecorder.new { subject }
expected_query = "SELECT \"merge_requests\".* FROM \"merge_requests\" " \
"WHERE \"merge_requests\".\"id\" IN (#{merge_request_1.id}, #{merge_request_2.id})"
expect(recorded.log)
.to include("SELECT \"merge_requests\".* FROM \"merge_requests\" " \
"WHERE \"merge_requests\".\"id\" IN (#{merge_request_1.id}, #{merge_request_2.id})")
expect(recorded.log).to include(a_string_starting_with(expected_query))
end
end
......
......@@ -159,6 +159,9 @@ RSpec.configure do |config|
.with(:force_autodevops_on_by_default, anything)
.and_return(false)
# Enable Marginalia feature for all specs in the test suite.
allow(Gitlab::Marginalia).to receive(:cached_feature_enabled?).and_return(true)
# The following can be removed once Vue Issuable Sidebar
# is feature-complete and can be made default in place
# of older sidebar.
......
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