Add remote? to SpanContext

api/lib/opentelemetry/trace/span_context.rb

@@ -7,25 +7,43 @@
 module OpenTelemetry
   module Trace
     # A SpanContext contains the state that must propagate to child {Span}s and across process boundaries.
-    # It contains the identifiers (a trace ID and span ID) associated with the {Span} and a set of
-    # {TraceFlags}.
+    # It contains the identifiers (a trace ID and span ID) associated with the {Span}, a set of
+    # {TraceFlags}, and a boolean indicating that the SpanContext was extracted from the wire.
     class SpanContext
-      attr_reader :trace_id, :span_id, :trace_flags
+      attr_reader :trace_id, :span_id, :trace_flags, :remote
 
+      # Returns a new {SpanContext}.
+      #
+      # @param [optional String] trace_id The trace ID associated with a {Span}.
+      # @param [optional String] span_id The span ID associated with a {Span}.
+      # @param [optional TraceFlags] trace_flags The trace flags associated with a {Span}.
+      # @param [optional Boolean] remote Whether the {SpanContext} was extracted from the wire.
+      # @return [SpanContext]
       def initialize(
         trace_id: Trace.generate_trace_id,
         span_id: Trace.generate_span_id,
-        trace_flags: TraceFlags::DEFAULT
+        trace_flags: TraceFlags::DEFAULT,
+        remote: false
       )
         @trace_id = trace_id
         @span_id = span_id
         @trace_flags = trace_flags
+        @remote = remote
       end
 
+      # Returns true if the {SpanContext} has a non-zero trace ID and non-zero span ID.
+      #
+      # @return [Boolean]
       def valid?
         @trace_id != INVALID_TRACE_ID && @span_id != INVALID_SPAN_ID
       end
 
+      # Returns true if the {SpanContext} was propagated from a remote parent.
+      #
+      # @return [Boolean]
+      alias remote? remote
+
+      # Represents an invalid {SpanContext}, with an invalid trace ID and an invalid span ID.
       INVALID = new(trace_id: INVALID_TRACE_ID, span_id: INVALID_SPAN_ID)
     end
   end

api/test/opentelemetry/trace/span_context_test.rb

@@ -23,6 +23,17 @@
     end
   end
 
+  describe '#remote?' do
+    it 'is false by default' do
+      span_context.wont_be(:remote?)
+    end
+
+    it 'reflects the value passed in' do
+      context = OpenTelemetry::Trace::SpanContext.new(remote: true)
+      context.must_be(:remote?)
+    end
+  end
+
   describe '#trace_id' do
     it 'reflects the value passed in' do
       trace_id = OpenTelemetry::Trace.generate_trace_id