Class: OpenTelemetry::Propagator::XRay::LambdaTextMapPropagator

Inherits:
TextMapPropagator show all
Defined in:
lib/opentelemetry/propagator/xray/lambda_text_map_propagator.rb

Overview

Implementation of AWS X-Ray Trace Header propagation with special handling for Lambda's _X_AMZN_TRACE_ID environment variable

Constant Summary collapse

AWS_TRACE_HEADER_ENV_KEY = 
'_X_AMZN_TRACE_ID'

Instance Method Summary collapse

Methods inherited from TextMapPropagator

#inject

Instance Method Details

#extract(carrier, context: Context.current, getter: Context::Propagation.text_map_getter) ⇒ Context

Extract trace context from the supplied carrier or from Lambda environment variable If extraction fails, the original context will be returned

Parameters:

  • carrier (Carrier) —

    The carrier to get the header from

  • context (optional Context) (defaults to: Context.current) —

    Context to be updated with the trace context extracted from the carrier. Defaults to +Context.current+.

  • getter (optional Getter) (defaults to: Context::Propagation.text_map_getter) —

    If the optional getter is provided, it will be used to read the header from the carrier, otherwise the default text map getter will be used.

Returns:

  • (Context) —

    context updated with extracted baggage, or the original context if extraction fails



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# File 'lib/opentelemetry/propagator/xray/lambda_text_map_propagator.rb', line 35

def extract(carrier, context: Context.current, getter: Context::Propagation.text_map_getter)
  # Check if the original input context already has a valid span
  span_context = Trace.current_span(context).context
  # If original context is valid, just return it - do not extract from carrier
  return context if span_context.valid?

  # First try to extract from the carrier using the standard X-Ray propagator
  xray_context = super

  # Check if we successfully extracted a context from the carrier
  span_context = Trace.current_span(xray_context).context
  return xray_context if span_context.valid?

  # If not, check for the Lambda environment variable
  trace_header = ENV.fetch(AWS_TRACE_HEADER_ENV_KEY, nil)
  return xray_context unless trace_header

  # Create a carrier with the trace header and extract from it
  env_carrier = { XRAY_CONTEXT_KEY => trace_header }
  super(env_carrier, context: xray_context, getter: getter)
rescue OpenTelemetry::Error
  context
end