Document how to register loggers

[DjebbZ]

Hi, long time no see IRL :)

I'm trying to slience the post-eval-logger because the data I want to inspect and play with is big, and logging it hides the Execution point haha.

I've tried registering globally a no-op function with (sc.api.logging/register-cs-logger :sc/spy-ep-post-eval-logger (fn [_])) but it didn't work. The only thing that worked was passing this function explicitly at call site of spy : (sc.api/spy {:sc/spy-ep-post-eval-logger (fn [_])} (my-code ...)).

Bug or mistake ? If it's a mistake, please correct me. In exchange you'll get a PR with documentation for this feature. Deal ?

[DjebbZ]

The bug exists in both "0.1.3" and "0.1.4".

And I think I have a hint at why. I'm using a REPL with the usual REPL-friendly reloaded workflow, but I've just remember that multimethods aren't REPL-friendly like that. So I've dived a little bit in the code and found that in spy-emit instead of calling the log-cs multimethod it directly calls sc.api.logging/log-spy-ep-post-eval or the version installed in the map. So registering a logger has no use here ?

[vvvvalvalval]

Hi, long time no see IRL :)

Hi! Yeah, a Paris Meetup should be announced soon :)

I've tried registering globally a no-op function with (sc.api.logging/register-cs-logger :sc/spy-ep-post-eval-logger (fn [_])) but it didn't work.

Yes, it's a mistake of usage, I think there are several misunderstandings to address here:

1. What you want is to register a 'Post-Eval' logger, which implements the notification sent after evaluation at an Execution Point, at evaluation-time. However, you are using sc.api.logging/register-cs-logger, which is intended to define a 'Code Site' logger, which implements the notification sent when compiling a Code Site, at macro-expansion-time.
2. In order to be a robust foundation for tooling, scope-capture does not currently allow you to "override global configuration" for loggers: instead, the recommended way to use your custom loggers is either to refer to them inline (as you did with (sc.api/spy {:sc/spy-ep-post-eval-logger (fn [_])} (my-code ...))) or to define your own spy macro with different defaults.

The Customization section of the Tutorial shows an example of defining both a custom Code Site Logger and a custom Post Eval Logger.

In your case, defining a silent Post-Eval Logger would consist of something like:

(defn noop-spy-post-eval 
  [_ep-data])

(def my-spy-opts
  ;; mind the syntax-quote '`'
  `{:sc/spy-ep-post-eval-logger noop-spy-post-eval})

(defmacro my-spy
  ([] (sc.api/spy-emit my-spy-opts nil &env &form))
  ([expr] (sc.api/spy-emit my-spy-opts expr &env &form))
  ([opts expr] (sc.api/spy-emit (merge my-spy-opts opts) expr &env &form)))

If you really wanted to change the configuration globally, you could use the following dark magic hack:

;; HACK changing the impl of the default Post Eval Logger via Var mutation
(alter-var-root #'sc.api.logging/log-spy-ep-post-eval 
  (constantly noop-spy-post-eval))

I would happily accept PRs that makes the doc clearer in this matter.

[DjebbZ]

My bad, I didn't see the Tutorial at all. What I ended up doing is copy-paste the slient Post-Eval logger snippet in my profile.boot and call (boot.user/my-spy (my-code ...)). The only difference is that I had to remove the syntax quote, otherwise it was thinking that the fully qualified symbol was from clojure.core. Dark macro magic...

I'll think on a PR.

[vvvvalvalval]

Alright, given that you didn't see the Tutorial I'll close this issue, but of course you are still welcome to open more specific issues or PRs regarding this topic.