Regex support for ActiveSupport::Notfications integration

With ActiveSupport notifications, you can use a regular expression to subscribe to events en masse [ref]:

ActiveSupport::Notifications.subscribe /regex/ do |*args|
  # events matching /regex/ are handled here
end

However, trying to use regular expressions in the Honeycomb configuration breaks:

Honeycomb.configure do |config|
  config.notification_events = [/regex/]
end

ActiveSupport::Notifications.instrument 'string_matching_regex'
#=> Exception: NoMethodError: undefined method `call' for nil:NilClass

What's happening is that

beeline-ruby/lib/honeycomb/integrations/active_support.rb

Line 55 in 0285e18

handlers[event] = block

just populates the handlers using the regex as the key:

handlers[/regex/] = block

But ActiveSupport will pass the exact event name string to the subscriber, so

beeline-ruby/lib/honeycomb/integrations/active_support.rb

Line 66 in 0285e18

handlers[name].call(name, span, payload)

will try to invoke the handler like

handlers['string_matching_regex'].call

which of course blows up.

This isn't as much of a bug as it is a feature request. We don't necessarily have to support regexes, but it'd be more consistent with the ActiveSupport::Notifications.subscribe interface.

This is a great suggestion, I think I'll leave it as a feature request for now unless you want to take it on?

Closed by #92.