Using instrumentation libraries

アプリを開発する際、作業を加速するためにサードパーティのライブラリやフレームワークを使用することがあるでしょう。 OpenTelemetryを使用してアプリを計装する場合、使用するサードパーティのライブラリやフレームワークにトレース、ログ、メトリクスを手動で追加するために時間を費やすことを避けたいことがあります。

多くのライブラリやフレームワークはすでにOpenTelemetryをサポートしているか、OpenTelemetryの計装を介してサポートされているため、テレメトリーを生成してオブザーバビリティバックエンドにエクスポートできます。

サードパーティのライブラリやフレームワークを使用しているアプリやサービスを計装する場合は、このページの手順に従って、ネイティブに計装されたライブラリと依存関係の計装ライブラリの使用方法を学んでください。

ネイティブに計装されたライブラリを使用する

デフォルトでOpenTelemetryサポートが付属しているライブラリの場合、アプリにOpenTelemetry SDKを追加して設定することで、そのライブラリから発行されるトレース、メトリクス、ログを取得できます。

ライブラリによっては、計装のために追加の構成が必要な場合があります。 詳細はライブラリごとのドキュメントをご覧ください。

• Elasticsearch Ruby Client

Use Instrumentation Libraries

If a library does not come with OpenTelemetry out of the box, you can use instrumentation libraries in order to generate telemetry data for a library or framework.

For example, if you are using Rails and enable opentelemetry-instrumentation-rails, your running Rails app will automatically generate telemetry data for inbound requests to your controllers.

Configuring all instrumentation libraries

OpenTelemetry Ruby provides the metapackage opentelemetry-instrumentation-all that bundles all ruby-based instrumentation libraries into a single package. It’s a convenient way to add telemetry for all your libraries with minimal effort:

gem 'opentelemetry-sdk'
gem 'opentelemetry-exporter-otlp'
gem 'opentelemetry-instrumentation-all'

and configure it early in your application lifecycle. See the example below using a Rails initializer:

# config/initializers/opentelemetry.rb
require 'opentelemetry/sdk'
require 'opentelemetry/exporter/otlp'
require 'opentelemetry/instrumentation/all'
OpenTelemetry::SDK.configure do |c|
  c.service_name = '<YOUR_SERVICE_NAME>'
  c.use_all() # enables all instrumentation!
end

This will install all instrumentation libraries and enable the ones that match up to libraries you’re using in your app.

Overriding configuration for specific instrumentation libraries

If you are enabling all instrumentation but want to override the configuration for a specific one, call use_all with a configuration map parameter, where the key represents the library, and the value is its specific configuration parameter.

For example, here’s how you can install all instrumentations except the Redis instrumentation into your app:

require 'opentelemetry/sdk'
require 'opentelemetry/instrumentation/all'

OpenTelemetry::SDK.configure do |c|
  config = {'OpenTelemetry::Instrumentation::Redis' => { enabled: false }}
  c.use_all(config)
end

To override more instrumentation, add another entry in the config map.

Overriding configuration for specific instrumentation libraries with environment variables

You can also disable specific instrumentation libraries using environment variables. An instrumentation disabled by an environment variable takes precedence over local config. The convention for environment variable names is the library name, upcased with :: replaced by underscores, OPENTELEMETRY shortened to OTEL_LANG, and _ENABLED appended.

For example, the environment variable name for OpenTelemetry::Instrumentation::Sinatra is OTEL_RUBY_INSTRUMENTATION_SINATRA_ENABLED.

export OTEL_RUBY_INSTRUMENTATION_SINATRA_ENABLED=false

Configuring specific instrumentation libraries

If you prefer more selectively installing and using only specific instrumentation libraries, you can do that too. For example, here’s how to use only Sinatra and Faraday, with Faraday being configured with an additional configuration parameter.

First, install the specific instrumentation libraries you know you want to use:

gem install opentelemetry-instrumentation-sinatra
gem install opentelemetry-instrumentation-faraday

Then configure them:

require 'opentelemetry/sdk'

# install all compatible instrumentation with default configuration
OpenTelemetry::SDK.configure do |c|
  c.use 'OpenTelemetry::Instrumentation::Sinatra'
  c.use 'OpenTelemetry::Instrumentation::Faraday', { opt: 'value' }
end

Configuring specific instrumentation libraries with environment variables

You can also define the option for specific instrumentation libraries using environment variables. By convention, the environment variable will be the name of the instrumentation, upcased with :: replaced by underscores, OPENTELEMETRY shortened to OTEL_{LANG}, and _CONFIG_OPTS appended.

For example, the environment variable name for OpenTelemetry::Instrumentation::Faraday is OTEL_RUBY_INSTRUMENTATION_FARADAY_CONFIG_OPTS. A value of peer_service=new_service;span_kind=client overrides the options set from previous section for Faraday.

export OTEL_RUBY_INSTRUMENTATION_FARADAY_CONFIG_OPTS="peer_service=new_service;span_kind=client"

The following table lists the acceptable format for values according to the option data type:

Next steps

Instrumentation libraries are the easiest way to generate lots of useful telemetry data about your Ruby apps. But they don’t generate data specific to your application’s logic! To do that, you’ll need to enrich the instrumentation from instrumentation libraries with your own instrumentation code.