Register Sentry's ErrorSubscriber for Rails 7.0+ apps (#1705)

* Register Sentry's ErrorSubscriber for Rails 7.0+ apps

* Mark captured exceptions to avoid duplicated reporting

* Prevent ActiveSupport::ExecutionContext pollute reported events in tests

* Update changelog

CHANGELOG.md

@@ -3,6 +3,7 @@
 ### Features
 
 - Support serializing ActiveRecord job arguments in global id form [#1688](https://github.com/getsentry/sentry-ruby/pull/1688)
+- Register Sentry's ErrorSubscriber for Rails 7.0+ apps [#1705](https://github.com/getsentry/sentry-ruby/pull/1705)
 
 ## 5.0.2
 

sentry-rails/lib/sentry/rails/error_subscriber.rb

@@ -0,0 +1,20 @@
+module Sentry
+  module Rails
+    # This is not a user-facing class. You should use it with Rails 7.0's error reporter feature and its interfaces.
+    # See https://github.com/rails/rails/blob/main/activesupport/lib/active_support/error_reporter.rb for more information.
+    class ErrorSubscriber
+      def report(error, handled:, severity:, context:)
+        # a component may already have an integration to capture exceptions while its operation is also wrapped inside an `app.executor.wrap` (e.g. ActionCable)
+        # in such condition, the exception would be captured repeatedly. it usually happens in this order:
+        #
+        # 1. exception captured and reported by the component integration and re-raised
+        # 2. exception captured by the executor, which then reports it with executor.error_reporter
+        #
+        # and because there's no direct communication between the 2 callbacks, we need a way to identify if an exception has been captured before
+        # using a Sentry-specific intance variable should be the last impactful way
+        return if error.instance_variable_get(:@__sentry_captured)
+        Sentry::Rails.capture_exception(error, level: severity, contexts: { "rails.error" => context }, tags: { handled: handled })
+      end
+    end
+  end
+end

sentry-rails/lib/sentry/rails/railtie.rb

@@ -46,6 +46,8 @@ class Railtie < ::Rails::Railtie
       setup_backtrace_cleanup_callback
       inject_breadcrumbs_logger
       activate_tracing
+
+      register_error_subscriber(app) if ::Rails.version.to_f >= 7.0
     end
 
     runner do
@@ -115,5 +117,10 @@ def activate_tracing
         Sentry::Rails::Tracing.patch_active_support_notifications
       end
     end
+
+    def register_error_subscriber(app)
+      require "sentry/rails/error_subscriber"
+      app.executor.error_reporter.subscribe(Sentry::Rails::ErrorSubscriber.new)
+    end
   end
 end

sentry-rails/spec/sentry/rails_spec.rb

@@ -207,4 +207,33 @@
       expect(Sentry.configuration.trusted_proxies).to eq(["5.5.5.5"])
     end
   end
+
+  describe "error reporter integration", skip: Rails.version.to_f < 7.0 do
+    before do
+      make_basic_app
+    end
+
+    it "registers Sentry::Rails::ErrorSubscriber to Rails" do
+      Rails.error.report(Exception.new, handled: false)
+
+      expect(transport.events.count).to eq(1)
+
+      ActiveSupport.error_reporter.report(Exception.new, handled: false)
+
+      expect(transport.events.count).to eq(2)
+    end
+
+    it "sets correct contextual data to the reported event" do
+      Rails.error.handle(severity: :info, context: { foo: "bar" }) do
+        1/0
+      end
+
+      expect(transport.events.count).to eq(1)
+
+      event = transport.events.first
+      expect(event.tags).to eq({ handled: true })
+      expect(event.level).to eq(:info)
+      expect(event.contexts).to include({ "rails.error" => { foo: "bar" }})
+    end
+  end
 end

sentry-rails/spec/support/test_rails_app/app.rb

@@ -166,6 +166,11 @@ def make_basic_app
   # the callbacks duplicate after each time we initialize the application and cause issues when they're executed
   ActiveSupport::Executor.reset_callbacks(:run)
   ActiveSupport::Executor.reset_callbacks(:complete)
+
+  # Rails uses this module to set a global context for its ErrorReporter feature.
+  # this needs to be cleared so previously set context won't pollute later reportings (see ErrorSubscriber).
+  ActiveSupport::ExecutionContext.clear if defined?(ActiveSupport::ExecutionContext)
+
   if defined?(ActionCable)
     ActionCable::Channel::Base.reset_callbacks(:subscribe)
     ActionCable::Channel::Base.reset_callbacks(:unsubscribe)

sentry-ruby/lib/sentry/hub.rb

@@ -102,7 +102,10 @@ def capture_exception(exception, **options, &block)
 
       return unless event
 
-      capture_event(event, **options, &block)
+      capture_event(event, **options, &block).tap do
+        # mark the exception as captured so we can use this information to avoid duplicated capturing
+        exception.instance_variable_set(:@__sentry_captured, true)
+      end
     end
 
     def capture_message(message, **options, &block)