update one more script to run otlp metrics exporter

examples/metrics_sdk/README.md

@@ -1,29 +1,73 @@
-# OpenTelemetry Ruby Example
+# OpenTelemetry Ruby Metrics SDK Example
 
-## HTTP
+### metrics_collect.rb
 
-This is a simple example that demonstrates tracing an HTTP request from client to server. The example shows several aspects of tracing, such as:
+Running the script to see the metric data from console
 
-* Using the `TracerProvider`
-* Span Attributes
-* Using the console exporter
+```sh
+ruby metrics_collect.rb
+```
+
+### metrics_collect_otlp.rb
+
+**WARN: this example doesn't work on alpine aarch64 container due to grpc installation issue.**
+
+This example test both metrics sdk and metrics otlp http exporter.
 
-### Running the example
+You can view the metrics in your favored backend (e.g. jaeger).
 
-Install gems
+#### 1. Setup the local opentelemetry-collector.
+
+e.g.
 ```sh
-bundle install
+docker pull otel/opentelemetry-collector
+docker run --rm -v $(pwd)/config.yaml:/etc/otel/config.yaml -p 4317:4317 -p 4318:4318 otel/opentelemetry-collector --config /etc/otel/config.yaml
 ```
+Sample config.yaml
+```yaml
+receivers:
+  otlp:
+    protocols:
+      grpc:
+      http:
+      # Default endpoints: 0.0.0.0:4317 for gRPC and 0.0.0.0:4318 for HTTP
 
-Start the server
-```sh
-ruby server.rb
+exporters:
+  logging:
+    loglevel: debug
+
+processors:
+  batch:
+
+service:
+  pipelines:
+    traces:
+      receivers: [otlp]
+      processors: [batch]
+      exporters: [logging]
+    metrics:
+      receivers: [otlp]
+      processors: [batch]
+      exporters: [logging]
 ```
 
-In a separate terminal window, run the client to make a single request:
-```sh
-ruby client.rb
+More information on how to setup the otel collector in [quick start](https://opentelemetry.io/docs/collector/quick-start/).
+
+#### 2. Assign endpoint value to destinated address
+
+e.g.
+```
+# Using environment variable
+ENV['OTEL_EXPORTER_OTLP_METRICS_ENDPOINT'] = 'http://host.docker.internal:4318/v1/metrics'
+
+# Or using export command
+export OTEL_EXPORTER_OTLP_METRICS_ENDPOINT=http://host.docker.internal:4318/v1/metrics
 ```
 
-You should see console exporter output for both the client and server sessions.
+#### 3. Running the script to send metric data to otlp collector
+
+```sh
+ruby metrics_collect_otlp.rb
+```
 
+You should see the metric data appearing in the collector.

examples/metrics_sdk/metrics_collect_otlp.rb

@@ -0,0 +1,34 @@
+# frozen_string_literal: true
+
+require 'bundler/inline'
+
+gemfile(true) do
+  source 'https://rubygems.org'
+  gem "opentelemetry-api"
+  gem "opentelemetry-common"
+  gem "opentelemetry-sdk"
+
+  gem 'opentelemetry-metrics-api', path: '../../metrics_api'
+  gem 'opentelemetry-metrics-sdk', path: '../../metrics_sdk'
+  gem 'opentelemetry-exporter-otlp-metrics', path: '../../exporter/otlp-metrics'
+
+end
+
+require 'opentelemetry/sdk'
+require 'opentelemetry-metrics-sdk'
+require 'opentelemetry-exporter-otlp-metrics'
+
+OpenTelemetry::SDK.configure
+
+console_metric_exporter = OpenTelemetry::Exporter::OTLP::MetricsExporter.new
+
+OpenTelemetry.meter_provider.add_metric_reader(console_metric_exporter)
+
+meter = OpenTelemetry.meter_provider.meter("SAMPLE_METER_NAME")
+
+histogram = meter.create_histogram('histogram', unit: 'smidgen', description: 'desscription')
+
+histogram.record(123, attributes: {'foo' => 'bar'})
+
+OpenTelemetry.meter_provider.metric_readers.each(&:pull)
+OpenTelemetry.meter_provider.shutdown