Ignore low-level Puma exceptions by default (#2055)

* Ignore low-level Puma exceptions by default

This is a follow-up to #2026. The idea is to ignore low-level Puma
exceptions by default, but allow users to opt-in to capturing them.

Please see comments in #2026
for more details.

* Update changelog

CHANGELOG.md

@@ -10,6 +10,7 @@
 ### Bug Fixes
 
 - Support Rails 7.1's show exception check [#2049](https://github.com/getsentry/sentry-ruby/pull/2049)
+- Ignore low-level Puma exceptions by default [#2055](https://github.com/getsentry/sentry-ruby/pull/2055)
 
 ## 5.9.0
 

sentry-ruby/lib/sentry/configuration.rb

@@ -257,6 +257,15 @@ def capture_exception_frame_locals=(value)
     # @!visibility private
     attr_reader :errors, :gem_specs
 
+    # These exceptions could enter Puma's `lowlevel_error_handler` callback and the SDK's Puma integration
+    # But they are mostly considered as noise and should be ignored by default
+    # Please see https://github.com/getsentry/sentry-ruby/pull/2026 for more information
+    PUMA_IGNORE_DEFAULT = [
+      'Puma::MiniSSL::SSLError',
+      'Puma::HttpParserError',
+      'Puma::HttpParserError501'
+    ].freeze
+
     # Most of these errors generate 4XX responses. In general, Sentry clients
     # only automatically report 5xx responses.
     IGNORE_DEFAULT = [
@@ -306,7 +315,7 @@ def initialize
       self.environment = environment_from_env
       self.enabled_environments = []
       self.exclude_loggers = []
-      self.excluded_exceptions = IGNORE_DEFAULT.dup
+      self.excluded_exceptions = IGNORE_DEFAULT + PUMA_IGNORE_DEFAULT
       self.inspect_exception_causes_for_exclusion = true
       self.linecache = ::Sentry::LineCache.new
       self.logger = ::Sentry::Logger.new(STDOUT)

sentry-ruby/spec/isolated/puma_spec.rb

@@ -77,6 +77,39 @@ def server_run(app, lowlevel_error_handler: nil, &block)
     end
   end
 
+  context "when puma raises its own errors" do
+    [Puma::MiniSSL::SSLError, Puma::HttpParserError, Puma::HttpParserError501].each do |error_class|
+      it "doesn't capture #{error_class}" do
+        app = proc { raise error_class.new("foo") }
+
+        res = server_run(app) do |server|
+          server.send_http_and_read("GET / HTTP/1.0\r\n\r\n")
+        end
+
+        expect(res).to match(/500 Internal Server Error/)
+        events = sentry_events
+        expect(events.count).to eq(0)
+      end
+
+      it "captures #{error_class} when it is removed from the SDK's config.excluded_exceptions" do
+        Sentry.configuration.excluded_exceptions.delete(error_class.name)
+
+        app = proc { raise error_class.new("foo") }
+
+        res = server_run(app) do |server|
+          server.send_http_and_read("GET / HTTP/1.0\r\n\r\n")
+        end
+
+        expect(res).to match(/500 Internal Server Error/)
+        events = sentry_events
+        expect(events.count).to eq(1)
+        event = events.first
+        expect(event.exception.values.first.type).to match(error_class.name)
+        expect(event.exception.values.first.value).to match("foo")
+      end
+    end
+  end
+
   context "when Sentry.capture_exception causes error" do
     it "doesn't affect the response" do
       expect(Sentry).to receive(:capture_exception).and_raise("bar")