Feature Request: Read process interleaved with stream assignment

[ad-si]

It would be cool to have a function a la

readProcessTimed
  :: MonadIO m	  
  => ProcessConfig stdin stdoutIgnored stderrIgnored	  
  -> m (ExitCode, [(ByteString, ByteString, ByteString)])

which would results in something like this:

( ExitSuccess,
    [ ( "2022-10-29T15:20:12.168Z", "stdout", "Hello World!" ) ] 
    , ( "2022-10-29T15:20:12.175Z", "stderr", "ERROR: World not available" ) ] 
    ]
)

• There should probably be a version with and without timestamp (or make it configurable)
• It should probably use a more elaborate data type than a tuple of strings

[tomjaguarpaw]

I don't think I follow. What do the timestamps refer to here? The first time some data was available on that stream?

[ad-si]

Well, that's up for debate I guess, but Google Cloud Functions for example uses a timestamp for each line (terminated by \n). I guess it's the moment the \n appears on the stream.

[tomjaguarpaw]

Personally I'd say that kind of thing belongs in a higher level library and that typed-process is too low-level for that. @snoyberg makes the final decision though.

[snoyberg]

I agree with @tomjaguarpaw's assessment.

[ad-si]

Ok, but even for a version without timestamps, but tags where each chunk came from?

( ExitSuccess,
    [ Stdout "Hello World!"
    , Stderr "ERROR: World not available"
    ]
)

[tomjaguarpaw]

Yes, even for that. How about this: you write something that does that, use it happily in production for a year, and then come back here with a PR saying "this is rock solid in production and really useful, would you like to incorporate it?". Then we're more likely to add it to the library.