THREESCALE-9682: Add support for OpenTelemetry (#405)

* Install OpenTelemetry gems

* Add support for OpenTelemetry

* Add env var to enable otel

`CONFIG_OPENTELEMETRY_ENABLED`

---------

Co-authored-by: Eguzki Astiz Lezaun <[email protected]>

Author: jlledom

Gemfile

@@ -61,6 +61,9 @@ gem 'redis-namespace', '~>1.8'
 gem 'rack', '~> 2.2.8'
 gem 'sinatra', '~> 2.2.4'
 gem 'sinatra-contrib', '~> 2.2.4'
+gem "opentelemetry-sdk", "~> 1.5"
+gem "opentelemetry-instrumentation-sinatra", "~> 0.24.1"
+gem "opentelemetry-exporter-otlp", "~> 0.29.0"
 # Optional external error logging services
 gem 'bugsnag', '~> 6', require: nil
 gem 'yabeda-prometheus', '~> 0.5.0'

Gemfile.lock

@@ -100,6 +100,11 @@ GEM
     fiber-annotation (0.2.0)
     fiber-local (1.0.0)
     gli (2.16.1)
+    google-protobuf (4.28.0)
+      bigdecimal
+      rake (>= 13)
+    googleapis-common-protos-types (1.15.0)
+      google-protobuf (>= 3.18, < 5.a)
     hiredis-client (0.22.1)
       redis-client (= 0.22.1)
     i18n (1.14.5)
@@ -134,6 +139,36 @@ GEM
       mini_portile2 (~> 2.8.2)
       racc (~> 1.4)
     openssl (3.2.0)
+    opentelemetry-api (1.4.0)
+    opentelemetry-common (0.21.0)
+      opentelemetry-api (~> 1.0)
+    opentelemetry-exporter-otlp (0.29.0)
+      google-protobuf (>= 3.18)
+      googleapis-common-protos-types (~> 1.3)
+      opentelemetry-api (~> 1.1)
+      opentelemetry-common (~> 0.20)
+      opentelemetry-sdk (~> 1.2)
+      opentelemetry-semantic_conventions
+    opentelemetry-instrumentation-base (0.22.6)
+      opentelemetry-api (~> 1.0)
+      opentelemetry-common (~> 0.21)
+      opentelemetry-registry (~> 0.1)
+    opentelemetry-instrumentation-rack (0.24.6)
+      opentelemetry-api (~> 1.0)
+      opentelemetry-instrumentation-base (~> 0.22.1)
+    opentelemetry-instrumentation-sinatra (0.24.1)
+      opentelemetry-api (~> 1.0)
+      opentelemetry-instrumentation-base (~> 0.22.1)
+      opentelemetry-instrumentation-rack (~> 0.21)
+    opentelemetry-registry (0.3.1)
+      opentelemetry-api (~> 1.1)
+    opentelemetry-sdk (1.5.0)
+      opentelemetry-api (~> 1.1)
+      opentelemetry-common (~> 0.20)
+      opentelemetry-registry (~> 0.2)
+      opentelemetry-semantic_conventions
+    opentelemetry-semantic_conventions (1.10.1)
+      opentelemetry-api (~> 1.0)
     pkg-config (1.1.9)
     power_assert (2.0.3)
     process-metrics (0.2.1)
@@ -276,6 +311,9 @@ DEPENDENCIES
   license_finder (~> 7.0)
   mocha (~> 1.3)
   nokogiri (~> 1.16.5)
+  opentelemetry-exporter-otlp (~> 0.29.0)
+  opentelemetry-instrumentation-sinatra (~> 0.24.1)
+  opentelemetry-sdk (~> 1.5)
   pkg-config (~> 1.1.7)
   pry (~> 0.14)
   pry-byebug (~> 3)

docs/configuration.md

@@ -10,6 +10,7 @@ variables.
 - [Integration with Porta](#integration-with-porta)
 - [Logging](#logging)
 - [Prometheus metrics](#prometheus-metrics)
+- [OpenTelemetry](#opentelemetry)
 - [Feature flags](#feature-flags)
 - [Async](#async)
 - [Performance](#performance)
@@ -356,6 +357,14 @@ print the logs in both formats.
 - Applies to: worker.
 - Format: integer.
 
+## OpenTelemetry
+
+### CONFIG_OPENTELEMETRY_ENABLED
+
+- Enables OpenTelemetry instrumentation
+- Optional. Defaults to `false`.
+- Applies to: listener.
+- Format: `true` or `false`.
 
 ## Feature flags
 

lib/3scale/backend/configuration.rb

@@ -49,6 +49,7 @@ def parse_int(value, default)
       config.add_section(:internal_api, :user, :password)
       config.add_section(:master, :metrics)
       config.add_section(:worker_prometheus_metrics, :enabled, :port)
+      config.add_section(:opentelemetry, :enabled)
 
       config.add_section(
           :async_worker,

lib/3scale/backend/opentelemetry.rb

@@ -0,0 +1,9 @@
+require 'opentelemetry/sdk'
+require 'opentelemetry/instrumentation/sinatra'
+require 'opentelemetry-exporter-otlp'
+require '3scale/backend/configuration'
+
+OpenTelemetry::SDK.configure do |c|
+  c.service_name = '3scale-backend'
+  c.use 'OpenTelemetry::Instrumentation::Sinatra'
+end if ThreeScale::Backend.configuration.opentelemetry.enabled

lib/3scale/backend/server.rb

@@ -1,4 +1,5 @@
 require '3scale/backend/util'
+require '3scale/backend/opentelemetry'
 
 module ThreeScale
   module Backend

openshift/3scale_backend.conf

@@ -74,4 +74,5 @@ ThreeScale::Backend.configure do |config|
   config.async_worker.max_pending_jobs = parse_int_env('CONFIG_ASYNC_WORKER_MAX_PENDING_JOBS')
   config.async_worker.seconds_before_fetching_more = parse_int_env('CONFIG_ASYNC_WORKER_WAIT_SECONDS_FETCHING')
   config.legacy_referrer_filters = parse_boolean_env('CONFIG_LEGACY_REFERRER_FILTERS')
+  config.opentelemetry.enabled = parse_boolean_env('CONFIG_OPENTELEMETRY_ENABLED')
 end