Reduce memory allocations during tag and metric serialization

lib/datadog/statsd/serialization/stat_serializer.rb

@@ -10,20 +10,20 @@ def initialize(prefix, global_tags: [])
           @tag_serializer = TagSerializer.new(global_tags)
         end
 
-        def format(name, delta, type, tags: [], sample_rate: 1)
-          name = formated_name(name)
+        def format(metric_name, delta, type, tags: [], sample_rate: 1)
+          metric_name = formatted_metric_name(metric_name)
 
           if sample_rate != 1
             if tags_list = tag_serializer.format(tags)
-              "#{@prefix_str}#{name}:#{delta}|#{type}|@#{sample_rate}|##{tags_list}"
+              "#{@prefix_str}#{metric_name}:#{delta}|#{type}|@#{sample_rate}|##{tags_list}"
             else
-              "#{@prefix_str}#{name}:#{delta}|#{type}|@#{sample_rate}"
+              "#{@prefix_str}#{metric_name}:#{delta}|#{type}|@#{sample_rate}"
             end
           else
             if tags_list = tag_serializer.format(tags)
-              "#{@prefix_str}#{name}:#{delta}|#{type}|##{tags_list}"
+              "#{@prefix_str}#{metric_name}:#{delta}|#{type}|##{tags_list}"
             else
-              "#{@prefix_str}#{name}:#{delta}|#{type}"
+              "#{@prefix_str}#{metric_name}:#{delta}|#{type}"
             end
           end
         end
@@ -37,17 +37,18 @@ def global_tags
         attr_reader :prefix
         attr_reader :tag_serializer
 
-        def formated_name(name)
-          if name.is_a?(String)
-            # DEV: gsub is faster than dup.gsub!
-            formated = name.gsub('::', '.')
+        def formatted_metric_name(metric_name)
+          formatted = Symbol === metric_name ? metric_name.name : metric_name.to_s
+
+          if formatted.include?('::')
+            formatted = formatted.gsub('::', '.')
+            formatted.tr!(':|@', '_')
+            formatted
+          elsif formatted.include?(':') || formatted.include?('@') || formatted.include?('|')
+            formatted.tr(':|@', '_')
           else
-            formated = name.to_s
-            formated.gsub!('::', '.')
+            formatted
           end
-
-          formated.tr!(':|@', '_')
-          formated
         end
       end
     end

lib/datadog/statsd/serialization/tag_serializer.rb

@@ -73,7 +73,9 @@ def to_tags_list(tags)
         end
 
         def escape_tag_content(tag)
-          tag.to_s.delete('|,')
+          tag = tag.to_s
+          return tag unless tag.include?('|')
+          tag.delete('|,')        
         end
 
         def dd_tags(env = ENV)

spec/statsd/serialization/stat_serializer_spec.rb

@@ -92,6 +92,22 @@
         expect(subject.format('somecount', 42, 'c', tags: message_tags, sample_rate: 0.5)).to eq 'swag.somecount:42|c|@0.5|#globaltag1:value1,msgtag2:value2'
       end
     end
+
+    context "metric name contains unsupported characters" do
+      it 'does not alter the provided metric name when containing ::' do
+        input = 'somecount::test'
+        output = subject.format(input, 1, 'c')
+        expect(output).to eq 'somecount.test:1|c'
+        expect(input).to eq 'somecount::test'
+      end
+
+      it 'does not alter the provided metric name when containing :|@' do
+        input = 'somecount:|@test'
+        output = subject.format(input, 1, 'c')
+        expect(output).to eq 'somecount___test:1|c'
+        expect(input).to eq 'somecount:|@test'
+      end
+    end
   end
 
   context 'benchmark' do

spec/statsd/serialization/tag_serializer_spec.rb

@@ -142,6 +142,13 @@
       it 'formats frozen tags correctly' do
         expect(subject.format(['name:foobarfoo'.freeze])).to eq 'name:foobarfoo'
       end
+
+      it 'does not alter the provided tag value when containing unsupported characters' do
+        input = 'name|foobar'
+        output = subject.format([input])
+        expect(output).to eq 'namefoobar'
+        expect(input).to eq 'name|foobar'
+      end
     end
 
     context '[testing management of env vars]' do