Remove metastruct_size (no usage)

Split set_metastruct into deep_merge_metastruct! and metastruct=

Author: vpellan

lib/datadog/tracing/metadata/metastruct.rb

@@ -5,16 +5,27 @@ module Tracing
     module Metadata
       # Adds complex structures tagging behavior through metastruct
       module Metastruct
-        def set_metastruct(metastruct)
-          self.metastruct.merge!(metastruct)
+        def metastruct=(second)
+          @metastruct = second
         end
 
-        def get_metastruct(key)
-          metastruct[key]
+        def deep_merge_metastruct!(second)
+          merger = proc do |_, v1, v2|
+            if v1.is_a?(Hash) && v2.is_a?(Hash)
+              v1.merge(v2, &merger)
+            elsif v1.is_a?(Array) && v2.is_a?(Array)
+              v1.concat(v2)
+            elsif v2.nil?
+              v1
+            else
+              v2
+            end
+          end
+          metastruct.merge!(second.to_h, &merger)
         end
 
-        def metastruct_size
-          metastruct.size
+        def get_metastruct(key)
+          metastruct[key]
         end
 
         protected

lib/datadog/tracing/trace_operation.rb

@@ -106,7 +106,7 @@ def initialize(
         # Generic tags
         set_tags(tags) if tags
         set_tags(metrics) if metrics
-        set_metastruct(metastruct) if metastruct
+        self.metastruct = metastruct if metastruct
 
         # State
         @root_span = nil
@@ -175,10 +175,6 @@ def get_metric(key)
         super || (root_span && root_span.get_metric(key))
       end
 
-      def get_metastruct(key)
-        super || (root_span && root_span.get_metastruct(key))
-      end
-
       def tags
         all_tags = {}
         all_tags.merge!(root_span&.tags || {}) if root_span
@@ -187,12 +183,6 @@ def tags
         all_tags
       end
 
-      def metastruct_size
-        size = super
-        size += root_span.metastruct_size if root_span
-        size
-      end
-
       # Returns true if the resource has been explicitly set
       #
       # @return [Boolean]

lib/datadog/tracing/transport/trace_formatter.rb

@@ -93,7 +93,7 @@ def set_trace_tags!
         def set_metastruct!
           return if partial?
 
-          root_span.set_metastruct(trace.send(:metastruct))
+          root_span.deep_merge_metastruct!(trace.send(:metastruct))
         end
 
         def tag_agent_sample_rate!

sig/datadog/tracing/metadata/metastruct.rbs

@@ -2,11 +2,11 @@ module Datadog
   module Tracing
     module Metadata
       module Metastruct
-        def set_metastruct: (Hash[String, untyped] metastruct) -> void
+        def metastruct=: (Hash[String, untyped] second) -> void
 
-        def get_metastruct: (String key) -> untyped
+        def deep_merge_metastruct!: (Hash[String, untyped] second) -> void
 
-        def metastruct_size: () -> Integer
+        def get_metastruct: (String key) -> untyped
 
         def metastruct: () -> Hash[String, untyped]
       end

spec/datadog/tracing/metadata/meta_struct_spec.rb

@@ -0,0 +1,83 @@
+require 'datadog/tracing/metadata/metastruct'
+
+RSpec.describe Datadog::Tracing::Metadata::Metastruct do
+  subject(:test_object) { test_class.new }
+  let(:test_class) { Class.new { include Datadog::Tracing::Metadata::Metastruct } }
+
+  describe '#metastruct=' do
+    subject(:metastruct_instance_var) { test_object.send(:metastruct) }
+
+    context 'when setting meta struct' do
+      before do
+        test_object.instance_variable_set(:@metastruct, preexisting_metastruct)
+        test_object.metastruct = new_metastruct
+      end
+
+      let(:preexisting_metastruct) { nil }
+
+      context 'with empty preexisting metastruct' do
+        let(:new_metastruct) { { 'key' => 'value' } }
+
+        it { is_expected.to eq({ 'key' => 'value' }) }
+      end
+
+      context 'with preexisting metastruct' do
+        let(:preexisting_metastruct) { { 'old_key' => 'old_value' } }
+
+        context 'with new key' do
+          let(:new_metastruct) { { 'new_key' => 'new_value' } }
+
+          it { is_expected.to eq({ 'new_key' => 'new_value' }) }
+        end
+
+        context 'with existing key' do
+          let(:new_metastruct) { { 'old_key' => 'new_value' } }
+
+          it { is_expected.to eq({ 'old_key' => 'new_value' }) }
+        end
+      end
+    end
+  end
+
+  describe '#deep_merge_metastruct!' do
+    subject(:metastruct_instance_var) { test_object.send(:metastruct) }
+
+    context 'when merging meta struct' do
+      before do
+        test_object.instance_variable_set(:@metastruct, preexisting_metastruct)
+        test_object.deep_merge_metastruct!(new_metastruct)
+      end
+
+      let(:preexisting_metastruct) { nil }
+
+      context 'with empty preexisting metastruct' do
+        let(:new_metastruct) { { 'key' => 'value' } }
+
+        it { is_expected.to eq({ 'key' => 'value' }) }
+      end
+
+      context 'with simple preexisting metastruct' do
+        let(:preexisting_metastruct) { { 'old_key' => 'old_value' } }
+
+        context 'with new key' do
+          let(:new_metastruct) { { 'new_key' => 'new_value' } }
+
+          it { is_expected.to eq({ 'old_key' => 'old_value', 'new_key' => 'new_value' }) }
+        end
+
+        context 'with existing key' do
+          let(:new_metastruct) { { 'old_key' => 'new_value' } }
+
+          it { is_expected.to eq({ 'old_key' => 'new_value' }) }
+        end
+      end
+
+      context 'with nested preexisting metastruct, containing arrays' do
+        let(:preexisting_metastruct) { { 'key' => { 'nested_key' => ['value1'] } } }
+        let(:new_metastruct) { { 'key' => { 'nested_key' => ['value2'], 'second_nested_key' => ['value3'] } } }
+
+        it { is_expected.to eq({ 'key' => { 'nested_key' => ['value1', 'value2'], 'second_nested_key' => ['value3'] } }) }
+      end
+    end
+  end
+end

spec/datadog/tracing/metadata/metastruct_spec.rb

@@ -1175,17 +1175,6 @@
     end
   end
 
-  describe '#set_metastruct' do
-    it 'sets metastruct' do
-      trace_op.set_metastruct({ 'foo' => 'bar', 'baz' => { 'value' => 42 } })
-      trace_op.measure('top') {}
-
-      trace = trace_op.flush!
-
-      expect(trace.send(:metastruct)).to eq({ 'foo' => 'bar', 'baz' => { 'value' => 42 } })
-    end
-  end
-
   describe '#build_span' do
     subject(:build_span) { trace_op.build_span(span_name, **span_options) }
     let(:span_name) { 'web.request' }

spec/datadog/tracing/trace_operation_spec.rb

@@ -164,7 +164,7 @@
         it { expect(trace_segment.send(:metrics)).to eq({ 'foo' => 42.0 }) }
       end
 
-      context ':metastruct do
+      context ':metastruct' do
         let(:options) { { metastruct: metastruct } }
         let(:metastruct) { { 'foo' => 'bar' } }