fix(bunny): headers property needs to exist (#661)

* [bunny] fix: headers property needs to exist

* add test for nil headers from producer

instrumentation/bunny/lib/opentelemetry/instrumentation/bunny/patch_helpers.rb

@@ -35,6 +35,7 @@ def self.destination_name(exchange, routing_key)
         def self.extract_context(properties)
           # use the receive span as parent context
           parent_context = OpenTelemetry.propagation.extract(properties[:tracer_receive_headers])
+          return [parent_context, nil] if properties[:headers].nil?
 
           # link to the producer context
           producer_context = OpenTelemetry.propagation.extract(properties[:headers])

instrumentation/bunny/test/opentelemetry/instrumentation/bunny/patch_helpers_test.rb

@@ -0,0 +1,36 @@
+# frozen_string_literal: true
+
+# Copyright The OpenTelemetry Authors
+#
+# SPDX-License-Identifier: Apache-2.0
+
+require_relative '../../../../lib/opentelemetry/instrumentation/bunny/patch_helpers'
+
+describe OpenTelemetry::Instrumentation::Bunny::PatchHelpers do
+  let(:properties) do
+    {
+      headers: {
+        'traceparent' => '00-eab67ae26433f603121bd5674149d9e1-2007f3325d3cb6d6-01'
+      },
+      tracer_receive_headers: {
+        'traceparent' => '00-cd52775b3cb38931adf5fa880f890c25-cddb52a470027489-01'
+      }
+    }
+  end
+
+  describe '.extract_context' do
+    it 'returns the parent context with links when headers from producer exists' do
+      parent_context, links = OpenTelemetry::Instrumentation::Bunny::PatchHelpers.extract_context(properties)
+      _(parent_context).must_be_instance_of(OpenTelemetry::Context)
+      _(links).must_be_instance_of(Array)
+      _(links.first).must_be_instance_of(OpenTelemetry::Trace::Link)
+    end
+
+    it 'returns the parent context with no links when headers from producer not present' do
+      properties.delete(:headers)
+      parent_context, links = OpenTelemetry::Instrumentation::Bunny::PatchHelpers.extract_context(properties)
+      _(parent_context).must_be_instance_of(OpenTelemetry::Context)
+      _(links).must_be_nil
+    end
+  end
+end

instrumentation/bunny/test/test_helper.rb

@@ -19,4 +19,5 @@
   c.error_handler = ->(exception:, message:) { raise(exception || message) }
   c.logger = Logger.new($stderr, level: ENV.fetch('OTEL_LOG_LEVEL', 'fatal').to_sym)
   c.add_span_processor SPAN_PROCESSOR
+  c.propagators = [OpenTelemetry::Trace::Propagation::TraceContext.text_map_propagator]
 end