Odigos will automatically instrument your services and record semantic spans from popular modules. Many users find the automatic instrumentation data sufficient for their needs. However, if there is anything specific to your application that you want to record, you can enrich the data by adding custom spans to your code. This is sometimes referred to as manual instrumentation.

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Use Cases

Examples of custom spans you might want to add to your code include:
  • Spans for the execution of some potentially heavy or slow computation in you service.
  • Tracing for internal or third party libraries for which you don’t have automatic or integrated instrumentation.
  • Spans to describe some logical operations in your business logic that are meaningful in your domain.

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Required Dependencies

Add the following dependencies to your project by running: 
gem install opentelemetry-sdk

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Creating a Span

To acquire a tracer: 
# If in a Rails app, this lives in config/initializers/opentelemetry.rb
require "opentelemetry/sdk"

OpenTelemetry::SDK.configure do |c|
  c.service_name = '<YOUR_SERVICE_NAME>'
end

# 'MyAppTracer' can be used throughout your code now
MyAppTracer = OpenTelemetry.tracer_provider.tracer('<YOUR_TRACER_NAME>')
To create a new span: 
require "opentelemetry/sdk"

def do_work
  MyAppTracer.in_span("do_work") do |span|
    # do some work that the 'do_work' span tracks!
  end
end

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Additional Information

For more use cases, see the OpenTelemetry Ruby API documentation.