In the last few weeks I've created a PHP Agent for the Elastic APM product and it would be great to get some feedback from the Elastic (APM) community on the interface and the developer experience. If you're a PHP developer I'd love to hear your thoughts!
Go have a look at https://github.com/frankkoornstra/elastic-apm-agent and let me know what you think.
A little background: (almost) the whole library is based on immutability. I don't want to force you into using specific dependencies for some stuff like the http client or the logger so for that it only relies on virtual packages for which you can choose any implementation you like. It's 100% covered by unit tests (although that obviously doesn't tell the whole story) and all behaviour is tested through Behat tests. Code quality is a little bit important to me so that explains the Scrutinizer quality score of 10.
Contributing (if you feel so inclined) is quite easy: there's a contributing document that tells you what's what. All tests are run on every PR so you'll get immediate feedback. You can run the tests yourself with the makefile.