Skip to content

Commit

Permalink
fix: use AS::N subscriber for serialize events (#1075)
Browse files Browse the repository at this point in the history
* fix: use AS::N subscriber for serialize events

The details for Context management (i.e. setting current span) are
already handled by the OTel ActiveSupport instrumentation. Reuse
the notifications subscriber here for ActiveModel serialization events.

Reworked the example app into two: one Rails which works with the usual
SDK configuration and one standalone (no Rails) to demonstrate that the
subscription needs to be made after the SDK configuration is complete.
If the subscription is created during instrumentation install, the
subscription's tracer will be a NO-OP API tracer and won't produce
spans.

* update comments to reference Rails components consistently

Co-authored-by: Kayla Reopelle <[email protected]>

* default to console exporter

... but leave OTLP exporter gem in dependencies so that a curious person
can override without code changes to send to some OTLP receiver by
setting the appropriate environment variables.

* differentiate example app output from trace console output

* fixup! default to console exporter

* fixup! differentiate example app output from trace console output

---------

Co-authored-by: Kayla Reopelle <[email protected]>
Co-authored-by: Ariel Valentin <[email protected]>
  • Loading branch information
3 people authored Dec 2, 2024
1 parent 2d07298 commit 92d59eb
Show file tree
Hide file tree
Showing 10 changed files with 199 additions and 98 deletions.
9 changes: 0 additions & 9 deletions instrumentation/active_model_serializers/example/Gemfile

This file was deleted.

This file was deleted.

74 changes: 74 additions & 0 deletions instrumentation/active_model_serializers/example/rails_app.rb
Original file line number Diff line number Diff line change
@@ -0,0 +1,74 @@
# frozen_string_literal: true

# Copyright The OpenTelemetry Authors
#
# SPDX-License-Identifier: Apache-2.0

require 'bundler/inline'

gemfile(true) do
source 'https://rubygems.org'

gem 'rails'
gem 'active_model_serializers'
gem 'opentelemetry-api'
gem 'opentelemetry-common'
gem 'opentelemetry-instrumentation-active_model_serializers', path: '../'
gem 'opentelemetry-sdk'
gem 'opentelemetry-exporter-otlp'
end

ENV['OTEL_TRACES_EXPORTER'] ||= 'console'
OpenTelemetry::SDK.configure do |c|
c.service_name = 'active_model_serializers_example'
c.use 'OpenTelemetry::Instrumentation::ActiveModelSerializers'
end

# no manual subscription trigger

at_exit do
OpenTelemetry.tracer_provider.shutdown
end

# TraceRequestApp is a minimal Rails application inspired by the Rails
# bug report template for Action Controller.
# The configuration is compatible with Rails 6.0
class TraceRequestApp < Rails::Application
config.root = __dir__
config.hosts << 'example.org'
credentials.secret_key_base = 'secret_key_base'

config.eager_load = false

config.logger = Logger.new($stdout)
Rails.logger = config.logger
end

# Rails app initialization will pick up the instrumentation Railtie
# and subscribe to Active Support notifications
TraceRequestApp.initialize!

ExampleAppTracer = OpenTelemetry.tracer_provider.tracer('example_app')

class TestModel
include ActiveModel::API
include ActiveModel::Serialization

attr_accessor :name

def attributes
{ 'name' => nil,
'screaming_name' => nil }
end

def screaming_name
ExampleAppTracer.in_span('screaming_name transform') do |span|
name.upcase
end
end
end

model = TestModel.new(name: 'test object')
serialized_model = ActiveModelSerializers::SerializableResource.new(model).serializable_hash

puts "\n*** The serialized object: #{serialized_model}"
57 changes: 57 additions & 0 deletions instrumentation/active_model_serializers/example/standalone.rb
Original file line number Diff line number Diff line change
@@ -0,0 +1,57 @@
# frozen_string_literal: true

# Copyright The OpenTelemetry Authors
#
# SPDX-License-Identifier: Apache-2.0

require 'bundler/inline'

gemfile(true) do
source 'https://rubygems.org'

gem 'active_model_serializers'
gem 'opentelemetry-api'
gem 'opentelemetry-common'
gem 'opentelemetry-instrumentation-active_model_serializers', path: '../'
gem 'opentelemetry-sdk'
gem 'opentelemetry-exporter-otlp'
end

ENV['OTEL_TRACES_EXPORTER'] ||= 'console'
OpenTelemetry::SDK.configure do |c|
c.service_name = 'active_model_serializers_example'
c.use_all
end

# without Rails and the Railtie automation, must manually trigger
# instrumentation subscription after SDK is configured
OpenTelemetry::Instrumentation::ActiveModelSerializers.subscribe

at_exit do
OpenTelemetry.tracer_provider.shutdown
end

ExampleAppTracer = OpenTelemetry.tracer_provider.tracer('example_app')

class TestModel
include ActiveModel::API
include ActiveModel::Serialization

attr_accessor :name

def attributes
{ 'name' => nil,
'screaming_name' => nil }
end

def screaming_name
ExampleAppTracer.in_span('screaming_name transform') do |span|
name.upcase
end
end
end

model = TestModel.new(name: 'test object')
serialized_model = ActiveModelSerializers::SerializableResource.new(model).serializable_hash

puts "\n*** The serialized object: #{serialized_model}"

This file was deleted.

Original file line number Diff line number Diff line change
Expand Up @@ -4,16 +4,24 @@
#
# SPDX-License-Identifier: Apache-2.0

require 'opentelemetry-instrumentation-active_support'

module OpenTelemetry
module Instrumentation
module ActiveModelSerializers
# Instrumentation class that detects and installs the ActiveModelSerializers instrumentation
class Instrumentation < OpenTelemetry::Instrumentation::Base
# Minimum supported version of the `active_model_serializers` gem
MINIMUM_VERSION = Gem::Version.new('0.10.0')

# ActiveSupport::Notification topics to which the instrumentation subscribes
SUBSCRIPTIONS = %w[
render.active_model_serializers
].freeze

install do |_config|
install_active_support_instrumenation
require_dependencies
register_event_handler
end

present do
Expand All @@ -24,24 +32,39 @@ class Instrumentation < OpenTelemetry::Instrumentation::Base
!defined?(::ActiveSupport::Notifications).nil? && gem_version >= MINIMUM_VERSION
end

def subscribe
SUBSCRIPTIONS.each do |subscription_name|
OpenTelemetry.logger.debug("Subscribing to #{subscription_name} notifications with #{_tracer}")
OpenTelemetry::Instrumentation::ActiveSupport.subscribe(_tracer, subscription_name, default_attribute_transformer)
end
end

private

def _tracer
self.class.instance.tracer
end

def gem_version
Gem::Version.new(::ActiveModel::Serializer::VERSION)
end

def require_dependencies
require_relative 'event_handler'
def install_active_support_instrumenation
OpenTelemetry::Instrumentation::ActiveSupport::Instrumentation.instance.install({})
end

def register_event_handler
::ActiveSupport::Notifications.subscribe(event_name) do |_name, start, finish, _id, payload|
EventHandler.handle(start, finish, payload)
end
def require_dependencies
require_relative 'railtie'
end

def event_name
'render.active_model_serializers'
def default_attribute_transformer
lambda { |payload|
{
'serializer.name' => payload[:serializer].name,
'serializer.renderer' => 'active_model_serializers',
'serializer.format' => payload[:adapter]&.class&.name || 'default'
}
}
end
end
end
Expand Down
Original file line number Diff line number Diff line change
@@ -0,0 +1,24 @@
# frozen_string_literal: true

# Copyright The OpenTelemetry Authors
#
# SPDX-License-Identifier: Apache-2.0

module OpenTelemetry
module Instrumentation
module ActiveModelSerializers # :nodoc:
def self.subscribe
Instrumentation.instance.subscribe
end

if defined?(::Rails::Railtie)
# This Railtie sets up subscriptions to relevant ActiveModelSerializers notifications
class Railtie < ::Rails::Railtie
config.after_initialize do
::OpenTelemetry::Instrumentation::ActiveModelSerializers.subscribe
end
end
end
end
end
end
Original file line number Diff line number Diff line change
Expand Up @@ -26,6 +26,7 @@ Gem::Specification.new do |spec|
spec.required_ruby_version = '>= 3.0'

spec.add_dependency 'opentelemetry-api', '~> 1.0'
spec.add_dependency 'opentelemetry-instrumentation-active_support', '>= 0.6.0'
spec.add_dependency 'opentelemetry-instrumentation-base', '~> 0.22.1'

spec.add_development_dependency 'active_model_serializers', '>= 0.10.0'
Expand Down
Original file line number Diff line number Diff line change
Expand Up @@ -7,16 +7,17 @@
require_relative '../../../test_helper'

# require instrumentation so we do not have to depend on the install hook being called
require_relative '../../../../lib/opentelemetry/instrumentation/active_model_serializers/event_handler'
require_relative '../../../../lib/opentelemetry/instrumentation/active_model_serializers/instrumentation'

describe OpenTelemetry::Instrumentation::ActiveModelSerializers::EventHandler do
describe OpenTelemetry::Instrumentation::ActiveModelSerializers::Instrumentation do
let(:instrumentation) { OpenTelemetry::Instrumentation::ActiveModelSerializers::Instrumentation.instance }
let(:exporter) { EXPORTER }
let(:span) { exporter.finished_spans.first }
let(:model) { TestHelper::Model.new(name: 'test object') }

before do
instrumentation.install
instrumentation.subscribe
exporter.reset

# this is currently a noop but this will future proof the test
Expand All @@ -38,7 +39,7 @@
_(exporter.finished_spans.size).must_equal 1

_(span).must_be_kind_of OpenTelemetry::SDK::Trace::SpanData
_(span.name).must_equal 'ModelSerializer render'
_(span.name).must_equal 'render.active_model_serializers'
_(span.attributes['serializer.name']).must_equal 'TestHelper::ModelSerializer'
_(span.attributes['serializer.renderer']).must_equal 'active_model_serializers'
_(span.attributes['serializer.format']).must_equal 'ActiveModelSerializers::Adapter::Attributes'
Expand All @@ -54,7 +55,7 @@
_(exporter.finished_spans.size).must_equal 1

_(span).must_be_kind_of OpenTelemetry::SDK::Trace::SpanData
_(span.name).must_equal 'ModelSerializer render'
_(span.name).must_equal 'render.active_model_serializers'
_(span.attributes['serializer.name']).must_equal 'TestHelper::ModelSerializer'
_(span.attributes['serializer.renderer']).must_equal 'active_model_serializers'
_(span.attributes['serializer.format']).must_equal 'TestHelper::Model'
Expand Down
Original file line number Diff line number Diff line change
Expand Up @@ -37,11 +37,15 @@
end
end

describe 'install' do
describe 'subscribe' do
before do
instrumentation.subscribe
end

it 'subscribes to ActiveSupport::Notifications' do
subscriptions = ActiveSupport::Notifications.notifier.instance_variable_get(:@string_subscribers)
subscriptions = subscriptions['render.active_model_serializers']
assert(subscriptions.detect { |s| s.is_a?(ActiveSupport::Notifications::Fanout::Subscribers::Timed) })
assert(subscriptions.detect { |s| s.is_a?(ActiveSupport::Notifications::Fanout::Subscribers::Evented) })
end
end
end

0 comments on commit 92d59eb

Please sign in to comment.