add example for x-ray sampling on rails

Author: jj22ee

sampler/xray/example/xray_sampling_on_rails_demonstration.ru

@@ -0,0 +1,101 @@
+# 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 'concurrent-ruby', '1.3.4'
+  gem 'rails', '~> 7.0.4'
+  gem 'puma'
+
+  gem 'opentelemetry-sdk'
+  gem 'opentelemetry-instrumentation-rails'
+  gem 'opentelemetry-sampler-xray', path: './../' # Use local version of the X-Ray Sampler
+  # gem 'opentelemetry-sampler-xray' # Use RubyGems version of the X-Ray Sampler
+end
+
+require "action_controller/railtie"
+require "action_mailer/railtie"
+require "rails/test_unit/railtie"
+
+class App < Rails::Application
+  config.root = __dir__
+  config.consider_all_requests_local = true
+
+  routes.append do
+    root to: 'welcome#index'
+    get "/test" => 'welcome#test'
+  end
+end
+
+class WelcomeController < ActionController::Base
+  def index
+    render inline: 'Successfully called "/" endpoint'
+  end
+
+  def test
+    render inline: 'Successfully called "/test" endpoint'
+  end
+end
+
+ENV['OTEL_TRACES_EXPORTER'] = 'console'
+ENV['OTEL_SERVICE_NAME'] = 'xray-sampler-on-rails-service'
+OpenTelemetry::SDK.configure do |c|
+  c.use_all({ 'OpenTelemetry::Instrumentation::ActiveRecord' => { enabled: false } })
+end
+
+OpenTelemetry.tracer_provider.sampler = OpenTelemetry::Sampler::XRay::AWSXRayRemoteSampler.new(resource:OpenTelemetry::SDK::Resources::Resource.create({
+  "service.name"=>"xray-sampler-on-rails-service"
+}))
+
+App.initialize!
+
+run App
+
+#### Running and using the Sample App
+# To run this example run the `rackup` command with this file
+# Example: rackup trace_request_demonstration.ru
+# Navigate to http://localhost:9292/
+# Spans for any requests sampled by the X-Ray Sampler will appear in the console
+
+#### Required configuration in the OpenTelemetry Collector
+# In order for sampling rules to be obtained from AWS X-Ray, the awsproxy extension
+# must be configured in the OpenTelemetry Collector, which will use your AWS credentials.
+# - https://github.com/open-telemetry/opentelemetry-collector-contrib/tree/main/extension/awsproxy#aws-proxy
+# Without the awsproxy extension, the X-Ray Sampler will use a fallback sampler
+# with a sampling strategy of "1 request/second, plus 5% of any additional requests"
+
+#### Testing out configurable X-Ray Sampling Rules against the "service.name" resource attribute.
+# Create a new Sampling Rule with the following matching criteria in AWS CloudWatch Settings for X-Ray Traces.
+# - https://console.aws.amazon.com/cloudwatch/home#xray:settings/sampling-rules
+    # Matching Criteria
+    # ServiceName = xray-sampler-on-rails-service
+    # ServiceType = *
+    # Host = *
+    # ResourceARN = *
+    # HTTPMethod = *
+    # URLPath = *
+# For the above matching criteria, try out the following settings to sample or not sample requests
+# - Limit to 0r/sec then 0 fixed rate
+# - Limit to 1r/sec then 0 fixed rate (May take 30 seconds for this setting to apply)
+# - Limit to 0r/sec then 100% fixed rate
+
+#### Testing out configurable X-Ray Sampling Rules against the "/test" endpoint in this sample app.
+# Create a new Sampling Rule with the following matching criteria in AWS CloudWatch Settings for X-Ray Traces.
+# - https://console.aws.amazon.com/cloudwatch/home#xray:settings/sampling-rules
+    # Matching Criteria
+    # ServiceName = *
+    # ServiceType = *
+    # Host = *
+    # ResourceARN = *
+    # HTTPMethod = *
+    # URLPath = /test
+# For the above matching criteria, try out the following settings to sample or not sample requests
+# - Limit to 0r/sec then 0 fixed rate
+# - Limit to 1r/sec then 0 fixed rate (May take 30 seconds for this setting to apply)
+# - Limit to 0r/sec then 100% fixed rate