Add RSpec listener to report slow tests to Sentryrs-slow-specs-to-sentry

When configured, this listener will report any example that has a run
time exceeding a defined threshold to Sentry.

1 files changed, 80 insertions, 0 deletions

diff --git a/spec/support/listeners/slow_example_listener.rb b/spec/support/listeners/slow_example_listener.rb
new file mode 100644
index 00000000000..80b7def7483
--- /dev/null
+++ b/spec/support/listeners/slow_example_listener.rb
@@ -0,0 +1,80 @@
+# frozen_string_literal: true
+
+# Reports slow example runtimes to a configured Sentry DSN
+class SlowExampleListener
+  # Maximum execution time for a single example
+  DEFAULT_THRESHOLD = 10.0
+
+  # Type-specific maximum execution times for a single example
+  TYPE_THRESHOLDS = {
+    feature: -> (meta) { meta[:js] ? 20.0 : DEFAULT_THRESHOLD }
+  }.freeze
+
+  def self.enabled?
+    (ENV['CI'] || ENV['ENABLE_RSPEC_TIMINGS']) &&
+      ENV['RSPEC_TIMINGS_DSN'].present?
+  end
+
+  def initialize
+    @raven = Raven::Instance.new(Raven::Context.new, Raven::Configuration.new)
+    @raven.configure do |config|
+      config.dsn = ENV['RSPEC_TIMINGS_DSN']
+      config.silence_ready = true
+    end
+  end
+
+  def threshold(meta)
+    threshold = TYPE_THRESHOLDS.fetch(meta[:type], DEFAULT_THRESHOLD)
+
+    if threshold.respond_to?(:call)
+      threshold.call(meta)
+    else
+      threshold
+    end
+  end
+
+  def example_passed(notification)
+    example = notification.example
+    metadata = example.metadata
+    result = example.execution_result
+    threshold = threshold(metadata)
+
+    if result.run_time > threshold
+      message = "Slow example: #{metadata[:location]}"
+
+      extra = metadata
+        .slice(:file_path, :line_number, :location, :full_description)
+        .merge({ run_time: result.run_time, threshold: threshold })
+
+      capture_message(
+        message,
+        extra: extra,
+        fingerprint: fingerprint(metadata),
+        tags: metadata.slice(:type, :js)
+      )
+    end
+  rescue StandardError => ex
+    @raven.capture_exception(ex)
+  end
+
+  private
+
+  def fingerprint(meta)
+    # Fingerprint on the full description, otherwise the example's location
+    # changing would create a new event
+    [Digest::SHA256.hexdigest(meta[:full_description])]
+  end
+
+  def capture_message(message, options = {})
+    # Temporarily disable WebMock so that Raven can post the message
+    WebMock.disable!
+    @raven.capture_message(message, options)
+    WebMock.enable!
+  end
+end
+
+if SlowExampleListener.enabled?
+  RSpec.configure do |config|
+    config.reporter.register_listener SlowExampleListener.new, :example_passed
+  end
+end