Ruby agent v8.14.0

v8.14.0

Version 8.14.0 of the agent restores desired Capistrano-based changelog lookup functionality when a deployment is performed, speeds up GUID generation, delivers support for instrumenting Rails custom event notifications, fixes potential compatibility issues with the RedisClient gem, and fixes bugs related to initialization in Rails.

• Deployment Recipe: Restore desired Capistrano-based changelog lookup behavior

  The New Relic Ruby agent offers a Capistrano recipe for recording app deployments. The recipe code was significantly cleaned up with PR#1498 which inadvertently changed the way the recipe handles the changelog for a deployment. Community member @arthurwozniak spotted and corrected this change in order to restore the desired changelog lookup functionality while retaining all of the previous cleanup. Thank you very much for your contribution, @arthurwozniak! PR#1653

• Speed up GUID generation

  The agent leverages random numbers in its GUID (globally unique identifier) generation and would previously always freshly calculate the result of 16^16 or 32^32 before generating a random number. Given that those 16^16 and 32^32 operations are expected, it makes sense to calculate their results up front and store them in constants to be referred to later. Doing so has resulted in a performance gain for the generation of GUIDs. Many thanks to @tungmq for contributing this optimisation and the benchmarks to support it! PR#1693

• Support for Rails ActiveSupport::Notifications for custom events

  When the new active_support_custom_events_names configuration parameter is set equal to an array of custom event names to subscribe to, the agent will now subscribe to each of the names specified and report instrumentation for the events when they take place. Creating custom events is simple and now reporting instrumentation for them to New Relic is simple as well. PR#1659

• Bugfix: Support older versions of the RedisClient gem, handle unknown Redis database index

  With version 8.13.0 of the agent, support was added for the redis-rb gem v5+ and the new RedisClient gem. With versions of RedisClient older than v0.11, the agent could cause the monitored application to crash when attempting to determine the Redis database index. Version 8.14.0 adds two related improvements. Firstly, support for RedisClient versions older than v0.11 has been added to get at the database index value. Secondly, the agent will no longer crash or impact the monitored application in the event that the database index cannot be obtained. Thank you very much to our community members @mbsmartee and @patatepartie for bringing this issue to our attention, for helping us determine how to best reproduce it, and for testing out the update. We appreciate your help! Issue#1650 PR#1673

• Bugfix: Defer agent startup in Rails until after application-defined initializers have run

  In Rails, the agent previously loaded before any application-defined initializers. This allowed initializers to reference the add_method_tracer API. However, this had the side-effect of forcing some framework libraries to load before initializers ran, preventing any configuration values related to these libraries from being applied. This fix provides an option to split initialization into two parts: load add_method_tracer before application-defined initializers and start the agent after application-defined initializers. This may cause other initializers to behave differently.

  If you'd like to use this feature, set defer_rails_initialization to true. It is false by default, but may become true by default in a future release.

  Furthermore, our Action View instrumentation was missing an ActiveSupport.on_load block around the code that loads our instrumentation.

  Thank you @jdelStrother for bringing this to our attention and collaborating with us on a fix. PR#1658

  Unfortunately, this bugfix is unreachable as written because the configuration value used to access the bugfix won't be applied until after initialization. Follow along for updates at Issue#662.