Module: Datadog::OpenTracer::TextMapPropagator

Extended by:
Ext::DistributedTracing, Propagator
Includes:
Ext::DistributedTracing
Defined in:
lib/ddtrace/opentracer/text_map_propagator.rb

Overview

OpenTracing propagator for Datadog::OpenTracer::Tracer

Constant Summary collapse

BAGGAGE_PREFIX = 
'ot-baggage-'.freeze

Constants included from Ext::DistributedTracing

Ext::DistributedTracing::B3_HEADER_SAMPLED, Ext::DistributedTracing::B3_HEADER_SINGLE, Ext::DistributedTracing::B3_HEADER_SPAN_ID, Ext::DistributedTracing::B3_HEADER_TRACE_ID, Ext::DistributedTracing::GRPC_METADATA_ORIGIN, Ext::DistributedTracing::GRPC_METADATA_PARENT_ID, Ext::DistributedTracing::GRPC_METADATA_SAMPLING_PRIORITY, Ext::DistributedTracing::GRPC_METADATA_TRACE_ID, Ext::DistributedTracing::HTTP_HEADER_ORIGIN, Ext::DistributedTracing::HTTP_HEADER_PARENT_ID, Ext::DistributedTracing::HTTP_HEADER_SAMPLING_PRIORITY, Ext::DistributedTracing::HTTP_HEADER_TRACE_ID, Ext::DistributedTracing::ORIGIN_KEY, Ext::DistributedTracing::PROPAGATION_EXTRACT_STYLE_ENV_OLD, Ext::DistributedTracing::PROPAGATION_INJECT_STYLE_ENV_OLD, Ext::DistributedTracing::PROPAGATION_STYLE_B3, Ext::DistributedTracing::PROPAGATION_STYLE_B3_SINGLE_HEADER, Ext::DistributedTracing::PROPAGATION_STYLE_DATADOG, Ext::DistributedTracing::PROPAGATION_STYLE_EXTRACT_ENV, Ext::DistributedTracing::PROPAGATION_STYLE_INJECT_ENV, Ext::DistributedTracing::SAMPLING_PRIORITY_KEY

Class Method Summary collapse

Methods included from Propagator

extract, inject

Class Method Details

.extract(carrier) ⇒ SpanContext?

Extract a SpanContext in TextMap format from the given carrier.

Parameters:

  • carrier (Carrier) —

    A carrier object of TextMap type

Returns:

  • (SpanContext, nil) —

    the extracted SpanContext or nil if none could be found



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# File 'lib/ddtrace/opentracer/text_map_propagator.rb', line 40

def extract(carrier)
  # First extract & build a Datadog context
  headers = DistributedHeaders.new(carrier)

  datadog_context = if headers.valid?
                      Datadog::Context.new(
                        trace_id: headers.trace_id,
                        span_id: headers.parent_id,
                        sampling_priority: headers.sampling_priority,
                        origin: headers.origin
                      )
                    else
                      Datadog::Context.new
                    end

  # Then extract any other baggage
  baggage = {}
  carrier.each do |key, value|
    baggage[item_to_baggage(key)] = value if baggage_item?(key)
  end

  SpanContextFactory.build(datadog_context: datadog_context, baggage: baggage)
end

.inject(span_context, carrier) ⇒ Object

Inject a SpanContext into the given carrier

Parameters:



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# File 'lib/ddtrace/opentracer/text_map_propagator.rb', line 19

def inject(span_context, carrier)
  # Inject Datadog trace properties
  span_context.datadog_context.tap do |datadog_context|
    carrier[HTTP_HEADER_TRACE_ID] = datadog_context.trace_id
    carrier[HTTP_HEADER_PARENT_ID] = datadog_context.span_id
    carrier[HTTP_HEADER_SAMPLING_PRIORITY] = datadog_context.sampling_priority
    carrier[HTTP_HEADER_ORIGIN] = datadog_context.origin
  end

  # Inject baggage
  span_context.baggage.each do |key, value|
    carrier[BAGGAGE_PREFIX + key] = value
  end

  nil
end