Tracing on the shoulders of giants
Jacek Królikowski
Story time!
"The eager rate-limter"
"Standard approach"
def suspicious_function(arg1, arg2, opts \\ []) do
IO.inspect {arg1, arg2, opts} # Logging the arguments
# do some work here
# ret = do_some_more_work()
IO.inspect ret
end
Debugging, the Erlang way
- "trace bifs" (erlang:trace_pattern/3)
- very powerful
- very not user friendly
- OTP dbg
- still not very user friendly
- it's easy to overload the node
-
redbug (!)
- easy to use
- production-friendly
- still very powerful
:redbug example in Erlang
(Audience participation)
-
:ets.lookup
-
Acme.Palindrome.is_palindrome?("don't nod")
Rate-limiting story conclusion
redbug is great anyways!
Birth of
- Elixir syntax
- the same redbug power*
- argument matching
- remote nodes
- targetting individual processes
- analogous API, you can use them interchangeably
- now available on hex.pm!
Takeaways
- It's worth it to know Erlang syntax sometimes
- redbug is awesome
- Rexbug is a thing
- There are other tracing debuggers (!)
- fishcakez/dbg
- liveforeverx/exrun
- andytill/erlyberly (GUI)
- ferd/recon (Erlang)
Links
- https://github.com/massemanet/redbug
- https://massemanet.github.io/eper/redbug
-
https://github.com/nietaki/rexbug
- (almost feature complete, feel free to contribute)
- https://slides.com/nietaki/tracing-on-the-shoulders-of-giants
Tracing on the shoulders of giants
By Jacek Królikowski
Tracing on the shoulders of giants
The Erlang ecosystem comes with many almost magical tools. But sometimes using them in the Elixir context is less than straightforward... Or is it?
