Module: Datadog::DistributedTracing::Headers::B3

Includes:
Ext::DistributedTracing
Defined in:
lib/ddtrace/distributed_tracing/headers/b3.rb

Overview

B3 provides helpers to inject or extract headers for B3 style headers

Constant Summary

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, Ext::DistributedTracing::PROPAGATION_INJECT_STYLE_ENV, Ext::DistributedTracing::PROPAGATION_STYLE_B3, Ext::DistributedTracing::PROPAGATION_STYLE_B3_SINGLE_HEADER, Ext::DistributedTracing::PROPAGATION_STYLE_DATADOG, Ext::DistributedTracing::SAMPLING_PRIORITY_KEY

Class Method Summary collapse

Class Method Details

.extract(env) ⇒ Object 



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# File 'lib/ddtrace/distributed_tracing/headers/b3.rb', line 25

def self.extract(env)
  # Extract values from headers
  # DEV: B3 doesn't have "origin"
  headers = Headers.new(env)
  trace_id = headers.id(B3_HEADER_TRACE_ID, 16)
  span_id = headers.id(B3_HEADER_SPAN_ID, 16)
  # We don't need to try and convert sampled since B3 supports 0/1 (AUTO_REJECT/AUTO_KEEP)
  sampling_priority = headers.number(B3_HEADER_SAMPLED)

  # Return early if this propagation is not valid
  return unless trace_id && span_id

  ::Datadog::Context.new(trace_id: trace_id,
                         span_id: span_id,
                         sampling_priority: sampling_priority)
end

.inject!(context, env) ⇒ Object 



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# File 'lib/ddtrace/distributed_tracing/headers/b3.rb', line 12

def self.inject!(context, env)
  return if context.nil?

  # DEV: We need these to be hex encoded
  env[B3_HEADER_TRACE_ID] = context.trace_id.to_s(16)
  env[B3_HEADER_SPAN_ID] = context.span_id.to_s(16)

  unless context.sampling_priority.nil?
    sampling_priority = DistributedTracing::Headers::Helpers.clamp_sampling_priority(context.sampling_priority)
    env[B3_HEADER_SAMPLED] = sampling_priority.to_s
  end
end