feat(otel): support span events

lib/datadog/opentelemetry/sdk/span_processor.rb

@@ -2,6 +2,7 @@
 
 require_relative 'trace/span'
 require_relative '../../tracing/span_link'
+require_relative '../../tracing/span_event'
 require_relative '../../tracing/trace_digest'
 
 module Datadog
@@ -31,6 +32,15 @@ def on_start(span, parent_context)
         #
         # @param [Span] span the {Span} that just ended.
         def on_finish(span)
+          unless span.events.nil?
+            span.datadog_span.span_events = span.events.map do |event|
+              Datadog::Tracing::SpanEvent.new(
+                event.name,
+                attributes: event.attributes,
+                time_unix_nano: event.timestamp
+              )
+            end
+          end
           span.datadog_span.finish(ns_to_time(span.end_timestamp))
         end
 

lib/datadog/tracing/span.rb

@@ -27,6 +27,7 @@ class Span
         :resource,
         :service,
         :links,
+        :events,
         :type,
         :start_time,
         :status,
@@ -60,7 +61,8 @@ def initialize(
         type: nil,
         trace_id: nil,
         service_entry: nil,
-        links: nil
+        links: nil,
+        events: nil
       )
         @name = Core::Utils::SafeDup.frozen_or_dup(name)
         @service = Core::Utils::SafeDup.frozen_or_dup(service)
@@ -90,6 +92,8 @@ def initialize(
 
         @links = links || []
 
+        @events = events || []
+
         # Mark with the service entry span metric, if applicable
         set_metric(Metadata::Ext::TAG_TOP_LEVEL, 1.0) if service_entry
       end
@@ -141,7 +145,8 @@ def to_hash
           span_id: @id,
           trace_id: @trace_id,
           type: @type,
-          span_links: @links.map(&:to_hash)
+          span_links: @links.map(&:to_hash),
+          events: @events.map(&:to_hash)
         }
 
         if stopped?

lib/datadog/tracing/span_operation.rb

@@ -35,7 +35,7 @@ class SpanOperation
         :start_time,
         :trace_id,
         :type
-      attr_accessor :links, :status
+      attr_accessor :links, :status, :span_events
 
       def initialize(
         name,
@@ -49,6 +49,7 @@ def initialize(
         trace_id: nil,
         type: nil,
         links: nil,
+        span_events: nil,
         id: nil
       )
         # Ensure dynamically created strings are UTF-8 encoded.
@@ -68,6 +69,7 @@ def initialize(
         @status = 0
         # stores array of span links
         @links = links || []
+        @span_events = span_events || []
 
         # start_time and end_time track wall clock. In Ruby, wall clock
         # has less accuracy than monotonic clock, so if possible we look to only use wall clock
@@ -455,6 +457,7 @@ def build_span
           type: @type,
           trace_id: @trace_id,
           links: @links,
+          events: @span_events,
           service_entry: parent.nil? || (service && parent.service != service)
         )
       end

lib/datadog/tracing/transport/serializable_trace.rb

@@ -72,6 +72,9 @@ def to_msgpack(packer = nil)
             packer.write_map_header(number_of_elements_to_write) # Set header with how many elements in the map
           end
 
+          # convert span events to tags
+          # span.set_tag('events', span.events.map(&:to_hash).to_json) if span.events
+
           # DEV: We use strings as keys here, instead of symbols, as
           # DEV: MessagePack will ultimately convert them to strings.
           # DEV: By providing strings directly, we skip this indirection operation.

spec/datadog/opentelemetry_spec.rb

@@ -626,6 +626,41 @@
       end
     end
 
+    describe '#add_event' do
+      subject! do
+        start_span
+        start_span.add_event('Exception was raised!', **event_options)
+        start_span.finish
+      end
+
+      let(:start_span) { otel_tracer.start_span('start-span', **span_options) }
+      let(:active_span) { Datadog::Tracing.active_span }
+
+      context 'with name, attributes and timestamp' do
+        let(:event_options) do
+          { attributes: { 'raised' => false, 'handler' => 'default', 'count' => 1 }, timestamp: 17206369349 }
+        end
+
+        it 'adds one event to the span' do
+          expect(span.events.count).to eq(1)
+          expect(span.events[0].name).to eq('Exception was raised!')
+          expect(span.events[0].time_unix_nano).to eq(17206369349000000000)
+          expect(span.events[0].attributes).to eq({ 'raised' => 'false', 'handler' => 'default', 'count' => '1' })
+        end
+      end
+
+      context 'without a timestamp or attributes' do
+        let(:event_options) { {} }
+
+        it 'adds one event with timestamp set to the current time and attributes set to an empty hash' do
+          expect(span.events.count).to eq(1)
+          expect(span.events[0].name).to eq('Exception was raised!')
+          expect(span.events[0].time_unix_nano / 1e9).to be_within(1).of(Time.now.to_f)
+          expect(span.events[0].attributes).to eq({})
+        end
+      end
+    end
+
     describe '#status=' do
       subject! do
         start_span