add test and update readme

Author: chris-olszewski

README.md

@@ -27,6 +27,7 @@ Prerequisites:
 * [encryption](encryption) - Demonstrates how to make a codec for end-to-end encryption.
 * [env_config](env_config) - Load client configuration from TOML files with programmatic overrides.
 * [message_passing_simple](message_passing_simple) - Simple workflow that accepts signals, queries, and updates.
+* [opentelemetry](opentelemetry) - Demonstrates how to use OpenTelemetry tracing and metrics with the Ruby SDK
 * [polling/infrequent](polling/infrequent) - Implement an infrequent polling mechanism using Temporal's automatic Activity Retry feature.
 * [rails_app](rails_app) - Basic Rails API application using Temporal workflows and activities.
 * [saga](saga) - Using undo/compensation using a very simplistic Saga pattern.
@@ -40,4 +41,3 @@ Prerequisites:
 To check format and test this repository, run:
 
     bundle exec rake
-

opentelemetry/README.md

@@ -1,4 +1,33 @@
-TODO: Doc that you have to use the below image, and how to see metrics and traces (traces are via
-Explore -> Tempo -> Query Type: Search).
+# OpenTelemetry Sample
 
-> docker run -p 3000:3000 -p 4317:4317 -p 4318:4318 --rm -ti grafana/otel-lgtm
+Demonstrates how to use OpenTelemetry tracing and metrics with the Ruby SDK
+
+## How to Run
+
+First, in another terminal start up a Grafana OpenTelemetry instance which will
+collect telemetry and provide the Grafana UI for viewing the data.
+
+```bash
+  docker compose up
+```
+
+In another terminal, start the worker
+
+```bash
+  bundle exec ruby worker.rb
+```
+
+Finally start the workflow
+
+```bash
+  bundle exec ruby starter.rb
+```
+
+You should be able to see the result in the terminal.
+
+To view the Grafana dashboard go to `http://localhost:3000`
+
+You can find the trace by clicking on the "Explore" tab,
+selecting "Tempo" as the data source, and switching the query type to "Search".
+
+There will be a trace for `my-service` containing the workflow trace.

opentelemetry/docker-compose.yaml

@@ -0,0 +1,8 @@
+services:
+  grafana-dashboard:
+    image: grafana/otel-lgtm:latest
+    tty: true
+    ports:
+      - 3000:3000
+      - 4317:4317
+      - 4318:4318

opentelemetry/util.rb

@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require 'opentelemetry/exporter/otlp'
 require 'opentelemetry/sdk'
 require 'temporalio/contrib/open_telemetry'
@@ -18,8 +20,8 @@ def self.configure_metrics_and_tracing
           )
         )
       )
-      # Globally configure the Ruby OpenTelemetry library for tracing purposes. As of this writing, OpenTelemetry Ruby does
-      # not support OTLP over gRPC, so we use the HTTP endpoint instead.
+      # Globally configure the Ruby OpenTelemetry library for tracing purposes. As of this writing, OpenTelemetry Ruby
+      # does not support OTLP over gRPC, so we use the HTTP endpoint instead.
       OpenTelemetry::SDK.configure do |c|
         c.service_name = 'my-service'
         c.use_all

opentelemetry/worker.rb

@@ -18,7 +18,7 @@
                    .record(1.23)
 
 # Create a client with the tracing interceptor set using the tracer
-tracer = OpenTelemetry.tracer_provider.tracer('temporal_ruby_sample', '0.1.0')
+tracer = OpenTelemetry.tracer_provider.tracer('opentelemetry_sample', '1.0.0')
 client = Temporalio::Client.connect(
   'localhost:7233',
   'default',

test/opentelemetry/greeting_workflow_test.rb

@@ -0,0 +1,51 @@
+# frozen_string_literal: true
+
+require 'test'
+require 'opentelemetry/compose_greeting_activity'
+require 'opentelemetry/greeting_workflow'
+require 'opentelemetry/sdk'
+require 'securerandom'
+require 'temporalio/client'
+require 'temporalio/contrib/open_telemetry'
+require 'temporalio/testing'
+require 'temporalio/worker'
+
+module OpenTelemetrySample
+  class GreetingWorkflowTest < Test
+    def test_workflow
+      # Setup in memory buffer for telemetry events
+      metrics_buffer = Temporalio::Runtime::MetricBuffer.new(1024)
+      runtime = Temporalio::Runtime.new(
+        telemetry: Temporalio::Runtime::TelemetryOptions.new(
+          metrics: Temporalio::Runtime::MetricsOptions.new(
+            buffer: metrics_buffer
+          )
+        )
+      )
+      tracer = OpenTelemetry.tracer_provider.tracer('opentelemetry_sample_test', '1.0.0')
+      Temporalio::Testing::WorkflowEnvironment.start_local(
+        runtime:,
+        interceptors: [Temporalio::Contrib::OpenTelemetry::TracingInterceptor.new(tracer)]
+      ) do |env|
+        # Run workflow in a worker
+        env.client
+        worker = Temporalio::Worker.new(
+          client: env.client,
+          task_queue: "tq-#{SecureRandom.uuid}",
+          activities: [ComposeGreetingActivity.new(tracer)],
+          workflows: [GreetingWorkflow]
+        )
+        result = worker.run do
+          handle = env.client.start_workflow(
+            GreetingWorkflow, 'Temporal',
+            id: "wf-#{SecureRandom.uuid}",
+            task_queue: worker.task_queue
+          )
+          handle.result
+        end
+        assert_equal 'Hello, Temporal!', result
+        assert !metrics_buffer.retrieve_updates.empty?
+      end
+    end
+  end
+end