Class: OpenTelemetry::Exporters::Datadog::Propagator

Inherits:
Object
  • Object
show all
Includes:
Context::Propagation::DefaultGetter, Context::Propagation::DefaultSetter
Defined in:
lib/opentelemetry/exporters/datadog/propagator.rb

Overview

Injects context into carriers using the W3C Trace Context format

Constant Summary collapse

TRACE_ID_KEY = 
'x-datadog-trace-id'
PARENT_ID_KEY = 
'x-datadog-parent-id'
SAMPLING_PRIORITY_KEY = 
'x-datadog-sampling-priority'
ORIGIN_KEY = 
'x-datadog-origin'
DD_ORIGIN = 
'_dd_origin'
ORIGIN_REGEX = 
/#{DD_ORIGIN}\=(.*?)($|,)/.freeze
DEFAULT_INJECTORS = 
[
  OpenTelemetry::Trace::Propagation::TraceContext.text_map_injector,
  OpenTelemetry::Baggage::Propagation.text_map_injector
].freeze
DEFAULT_EXTRACTORS = 
[
  OpenTelemetry::Trace::Propagation::TraceContext.rack_extractor,
  OpenTelemetry::Baggage::Propagation.rack_extractor
].freeze

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize ⇒ Propagator

Returns a new Propagator



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# File 'lib/opentelemetry/exporters/datadog/propagator.rb', line 37

def initialize
  # pass
  @truncation_helper = ::Datadog::DistributedTracing::Headers::Headers.new({})
end

Class Method Details

.auto_configure ⇒ Object 



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# File 'lib/opentelemetry/exporters/datadog/propagator.rb', line 102

def self.auto_configure
  default_propagator = new
  updated_injectors = DEFAULT_INJECTORS + [default_propagator]
  updated_extractors = DEFAULT_EXTRACTORS + [default_propagator]
  OpenTelemetry.propagation.http = OpenTelemetry::Context::Propagation::CompositePropagator.new(
    updated_injectors,
    updated_extractors
  )
end

Instance Method Details

#extract(carrier, context, &getter) {|Carrier, String| ... } ⇒ Context

Extract a remote Trace::SpanContext from the supplied carrier. Invalid headers will result in a new, valid, non-remote Trace::SpanContext.

Parameters:

  • carrier (Carrier) —

    The carrier to get the header from.

  • context (Context) —

    The context to be updated with extracted context

  • getter (optional Callable) —

    An optional callable that takes a carrier and a key and returns the value associated with the key. If omitted the default getter will be used which expects the carrier to respond to [] and []=.

Yields:

  • (Carrier, String) —

    if an optional getter is provided, extract will yield the carrier and the header key to the getter.

Returns:

  • (Context) —

    Updated context with span context from the header, or the original context if parsing fails.



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# File 'lib/opentelemetry/exporters/datadog/propagator.rb', line 76

def extract(carrier, context, &getter)
  getter ||= default_getter
  trace_id = getter.call(carrier, TRACE_ID_KEY) || getter.call(carrier, rack_helper(TRACE_ID_KEY))
  span_id = getter.call(carrier, PARENT_ID_KEY) || getter.call(carrier, rack_helper(PARENT_ID_KEY))
  sampled = getter.call(carrier, SAMPLING_PRIORITY_KEY) || getter.call(carrier, rack_helper(SAMPLING_PRIORITY_KEY))
  origin = getter.call(carrier, ORIGIN_KEY) || getter.call(carrier, rack_helper(ORIGIN_KEY))

  is_sampled = sampled.to_i.positive? ? 1 : 0

  tracestate = origin ? "#{DD_ORIGIN}=#{origin}" : nil

  return context if trace_id.nil? || span_id.nil?

  span_context = Trace::SpanContext.new(trace_id: Array(trace_id.to_i.to_s(16)).pack('H*'),
                                        span_id: Array(span_id.to_i.to_s(16)).pack('H*'),
                                        trace_flags: OpenTelemetry::Trace::TraceFlags.from_byte(is_sampled),
                                        tracestate: tracestate,
                                        remote: true)

  span = Trace::Span.new(span_context: span_context)
  Trace.context_with_span(span, parent_context: context)
rescue StandardError => e
  OpenTelemetry.logger.debug("error extracting datadog propagation, #{e.message}")
  context
end

#inject(carrier, context, &setter) ⇒ Object

Set the span context on the supplied carrier.

Parameters:

  • context (Context) —

    The active Context.

  • setter (optional Callable) —

    An optional callable that takes a carrier and a key and a value and assigns the key-value pair in the carrier. If omitted the default setter will be used which expects the carrier to respond to [] and []=.

Returns:

  • (Object) —

    the carrier with context injected



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# File 'lib/opentelemetry/exporters/datadog/propagator.rb', line 49

def inject(carrier, context, &setter)
  return carrier unless (span_context = span_context_from(context))

  sampled = span_context.trace_flags&.sampled? ? 1 : 0

  origin = get_origin_string(span_context.tracestate)
  setter ||= DEFAULT_SETTER
  setter.call(carrier, PARENT_ID_KEY, @truncation_helper.value_to_id(span_context.span_id.unpack1('H*'), 16).to_s)
  setter.call(carrier, TRACE_ID_KEY, @truncation_helper.value_to_id(span_context.trace_id.unpack1('H*'), 16).to_s)
  setter.call(carrier, SAMPLING_PRIORITY_KEY, sampled.to_s)
  setter.call(carrier, ORIGIN_KEY, origin) if origin

  carrier
end