Is it possible to use this gem with Newrelic?

[abezzub]

When I try to set this up on an app that also uses Newrelic it produces stack overflow error:

Unable to load application: SystemStackError: stack level too deep
/app/vendor/bundle/ruby/2.4.0/gems/newrelic_rpm-4.2.0.334/lib/new_relic/agent/instrumentation/rack.rb:20:in `>=': stack level too deep (SystemStackError)
from /app/vendor/bundle/ruby/2.4.0/gems/newrelic_rpm-4.2.0.334/lib/new_relic/agent/instrumentation/rack.rb:20:in `rack_version_supported?'
from /app/vendor/bundle/ruby/2.4.0/gems/newrelic_rpm-4.2.0.334/lib/new_relic/agent/instrumentation/rack.rb:12:in `version_supported?'
from /app/vendor/bundle/ruby/2.4.0/gems/newrelic_rpm-4.2.0.334/lib/new_relic/agent/instrumentation/rack.rb:32:in `middleware_instrumentation_enabled?'
from /app/vendor/bundle/ruby/2.4.0/gems/newrelic_rpm-4.2.0.334/lib/new_relic/agent/instrumentation/rack.rb:94:in `use_with_newrelic'
from /app/vendor/bundle/ruby/2.4.0/gems/rack-freeze-1.2.0/lib/rack/freeze/builder.rb:28:in `use'
from /app/vendor/bundle/ruby/2.4.0/gems/newrelic_rpm-4.2.0.334/lib/new_relic/agent/instrumentation/rack.rb:96:in `use_with_newrelic'
from /app/vendor/bundle/ruby/2.4.0/gems/rack-freeze-1.2.0/lib/rack/freeze/builder.rb:28:in `use'
from /app/vendor/bundle/ruby/2.4.0/gems/newrelic_rpm-4.2.0.334/lib/new_relic/agent/instrumentation/rack.rb:96:in `use_with_newrelic'
 ... 9702 levels...
from /app/vendor/bundle/ruby/2.4.0/gems/puma-3.9.0/lib/puma/cli.rb:77:in `run'
from /app/vendor/bundle/ruby/2.4.0/gems/puma-3.9.0/bin/puma:10:in `<top (required)>'
from /app/vendor/bundle/ruby/2.4.0/bin/puma:22:in `load'
from /app/vendor/bundle/ruby/2.4.0/bin/puma:22:in `<main>'

From what I understand newrelic also wraps all middleware classes in its own class, which conflicts with rack-freeze:
https://github.com/newrelic/rpm/blob/master/lib/new_relic/agent/instrumentation/rack.rb#L142

[ioquatix]

It should be, but I'll need to investigate exactly what is going on here.

[ioquatix]

We've got this working, and not had the same issues - if you change the order of loading new relic and rack/freeze - do you get any changes?

[abezzub]

Thanks, requiring newrelic before rack-freeze solved the issue.

[ioquatix]

Awesome! I was actually surprised to see how deep new relic messes with things.