Class: OpenTelemetry::Trace::Propagation::TraceContext::TextMapPropagator

Inherits:
Object
  • Object
show all
Defined in:
lib/opentelemetry/trace/propagation/trace_context/text_map_propagator.rb

Overview

Propagates trace context using the W3C Trace Context format

Instance Method Summary collapse

Instance Method Details

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

Extract trace context from the supplied carrier. 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

[View source]

47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
 
# File 'lib/opentelemetry/trace/propagation/trace_context/text_map_propagator.rb', line 47

def extract(carrier, context: Context.current, getter: Context::Propagation.text_map_getter)
  trace_parent_value = getter.get(carrier, TRACEPARENT_KEY)
  return context unless trace_parent_value

  tp = TraceParent.from_string(trace_parent_value)
  tracestate = Tracestate.from_string(getter.get(carrier, TRACESTATE_KEY))

  span_context = Trace::SpanContext.new(trace_id: tp.trace_id,
                                        span_id: tp.span_id,
                                        trace_flags: tp.flags,
                                        tracestate: tracestate,
                                        remote: true)
  span = OpenTelemetry::Trace.non_recording_span(span_context)
  OpenTelemetry::Trace.context_with_span(span, parent_context: context)
rescue OpenTelemetry::Error
  context
end

#fields ⇒ Array<String>

Returns the predefined propagation fields. If your carrier is reused, you should delete the fields returned by this method before calling inject.

Returns:

  • (Array<String>) —

    a list of fields that will be used by this propagator.

[View source]

69
70
71
 
# File 'lib/opentelemetry/trace/propagation/trace_context/text_map_propagator.rb', line 69

def fields
  FIELDS
end

#inject(carrier, context: Context.current, setter: Context::Propagation.text_map_setter) ⇒ Object

Inject trace context into the supplied carrier.

Parameters:

  • carrier (Carrier) —

    The mutable carrier to inject trace context into

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

    The context to read trace context from

  • setter (optional Setter) (defaults to: Context::Propagation.text_map_setter) —

    If the optional setter is provided, it will be used to write context into the carrier, otherwise the default text map setter will be used.

[View source]

26
27
28
29
30
31
32
33
 
# File 'lib/opentelemetry/trace/propagation/trace_context/text_map_propagator.rb', line 26

def inject(carrier, context: Context.current, setter: Context::Propagation.text_map_setter)
  span_context = Trace.current_span(context).context
  return unless span_context.valid?

  setter.set(carrier, TRACEPARENT_KEY, TraceParent.from_span_context(span_context).to_s)
  setter.set(carrier, TRACESTATE_KEY, span_context.tracestate.to_s) unless span_context.tracestate.empty?
  nil
end