Add before_send_transaction hook (#1989)

CHANGELOG.md

@@ -17,7 +17,20 @@
 
 - Add global event processor in OpenTelemetry `SpanProcessor` to link errors with transactions [#1983](https://github.com/getsentry/sentry-ruby/pull/1983)
 - Fix some inconsistencies in setting name/op/status in OpenTelemetry `SpanProcessor` [#1987](https://github.com/getsentry/sentry-ruby/pull/1987)
+- Add `config.before_send_transaction` hook [#1989](https://github.com/getsentry/sentry-ruby/pull/1989)
 
+    Users can now configure a `before_send_transaction` callback that runs similar to `before_send` but for transaction events.
+
+    ```rb
+    config.before_send_transaction = lambda do |event, hint|
+      # skip unimportant transactions or strip sensitive data
+      if event.transaction == "/healthcheck/route"
+        nil
+      else
+        event
+      end
+    end
+    ```
 
 ### Bug Fixes
 

sentry-ruby/lib/sentry/client.rb

@@ -122,6 +122,16 @@ def send_event(event, hint = nil)
         end
       end
 
+      if event_type == TransactionEvent::TYPE && configuration.before_send_transaction
+        event = configuration.before_send_transaction.call(event, hint)
+
+        if event.nil?
+          log_info("Discarded event because before_send_transaction returned nil")
+          transport.record_lost_event(:before_send, 'transaction')
+          return
+        end
+      end
+
       transport.send_event(event)
 
       event

sentry-ruby/lib/sentry/configuration.rb

@@ -72,6 +72,19 @@ class Configuration
     # @return [Proc]
     attr_reader :before_send
 
+    # Optional Proc, called before sending an event to the server
+    # @example
+    #   config.before_send_transaction = lambda do |event, hint|
+    #     # skip unimportant transactions or strip sensitive data
+    #     if event.transaction == "/healthcheck/route"
+    #       nil
+    #     else
+    #       event
+    #     end
+    #   end
+    # @return [Proc]
+    attr_reader :before_send_transaction
+
     # An array of breadcrumbs loggers to be used. Available options are:
     # - :sentry_logger
     # - :http_logger
@@ -287,6 +300,7 @@ def initialize
       self.instrumenter = :sentry
 
       self.before_send = nil
+      self.before_send_transaction = nil
       self.rack_env_whitelist = RACK_ENV_WHITELIST_DEFAULT
       self.traces_sample_rate = nil
       self.traces_sampler = nil
@@ -338,6 +352,12 @@ def before_send=(value)
       @before_send = value
     end
 
+    def before_send_transaction=(value)
+      check_callable!("before_send_transaction", value)
+
+      @before_send_transaction = value
+    end
+
     def before_breadcrumb=(value)
       check_callable!("before_breadcrumb", value)
 

sentry-ruby/spec/sentry/client/event_sending_spec.rb

@@ -224,6 +224,15 @@
           expect(event["tags"]["called"]).to eq(true)
         end
       end
+
+      it "doesn't apply before_send_transaction to Event" do
+        dbl = double("before_send_transaction")
+        allow(dbl).to receive(:call)
+        configuration.before_send_transaction = dbl
+
+        expect(dbl).not_to receive(:call)
+        subject.send_event(event)
+      end
     end
 
     it_behaves_like "Event in send_event" do
@@ -246,6 +255,26 @@
 
         subject.send_event(event)
       end
+
+      it "applies before_send_transaction callback before sending the event" do
+        configuration.before_send_transaction = lambda do |event, _hint|
+          if event.is_a?(Sentry::TransactionEvent)
+            event.tags[:called] = true
+          else
+            event["tags"]["called"] = true
+          end
+
+          event
+        end
+
+        subject.send_event(event)
+
+        if event.is_a?(Sentry::Event)
+          expect(event.tags[:called]).to eq(true)
+        else
+          expect(event["tags"]["called"]).to eq(true)
+        end
+      end
     end
 
     it_behaves_like "TransactionEvent in send_event" do
@@ -451,6 +480,20 @@
           expect(subject.transport).to have_recorded_lost_event(:before_send, 'event')
         end
       end
+
+      context "before_send_transaction returns nil" do
+        before do
+          configuration.before_send_transaction = lambda do |_event, _hint|
+            nil
+          end
+        end
+
+        it "records lost event" do
+          transaction_event = subject.event_from_transaction(Sentry::Transaction.new(hub: hub))
+          subject.send_event(transaction_event)
+          expect(subject.transport).to have_recorded_lost_event(:before_send, 'transaction')
+        end
+      end
     end
   end
 end

sentry-ruby/spec/sentry/configuration_spec.rb

@@ -127,6 +127,12 @@
     expect { subject.before_send = true }.to raise_error(ArgumentError, "before_send must be callable (or nil to disable)")
   end
 
+  it 'raises error when setting before_send_transaction to anything other than callable or nil' do
+    subject.before_send_transaction = -> {}
+    subject.before_send_transaction = nil
+    expect { subject.before_send_transaction = true }.to raise_error(ArgumentError, "before_send_transaction must be callable (or nil to disable)")
+  end
+
   it 'raises error when setting before_breadcrumb to anything other than callable or nil' do
     subject.before_breadcrumb = -> {}
     subject.before_breadcrumb = nil