Clojurians Log v2

How to retrieve items from multiple channels (each containing 0-1 items)? What I want to do is something like this:

(let [[err-ch data-ch] (a/split throwable? input-chan)
      result-ch (a/reduce extract-and-combine-data nil data-ch)
      errors-ch (a/into [] err-ch)]
  (a/go {:result (a/<! result-ch) :errors (a/<! errors-ch)}))

(a/go (let [[v ch] (a/alts! [result-ch errors-ch])
              res (if (= ch result-ch) v (a/<! result-ch))
              err (if (= ch errors-ch) v (a/<! errors-ch))]
          {:result res :errors err}))

How do you do troubleshooting with async? Normally I just put (def *args [arg1 ...]) into a function to capture its arguments and be able to play with it from the REPL but that is useless for channels as they will be already consumed. So I guess I need to make a copy of the channel using mult. Or?

@holyjak why do you need to process both the results and errors at the same time? why not have separate functions/go blocks?

1. I assume I must consume both channels so that the writer isn't blocked. 2. I want to report # errors vs # ordinary items.

@holyjak, If I correctly understood your problem: have you tried to consume all items into a collection to “unpack” data from the channels?

(a/into coll input-chan)

(split-with throwable? coll)

what about attaching the cat transducer to a chan?

Apparently, all data is already being streamed through the input-chan. Unless, I’m missing something. It would be a matter of consuming everything into a collection then splitting later. Considering that the input channel is to be closed signaling the completion.