Work with tail -f

[SimenB]

Would it be possible for this to work on stdin as well?

I'd like to tail a log and send it into this, and be able to interactively filter it. jq handles stdin just fine, if that matters 😄

[fiatjaf]

Well, it does work with stdin content. Actually, it only works with stdin, I think. It should work with other types of input.

echo {} | jiq actually raises an error, but it shouldn't. However, echo {"a": "b"} | jiq and other valid JSON over stdin works well. What error are you seeing?

[SimenB]

Yeah, that was imprecise of me, sorry.
What I meant is e.g. tailing a log using the follow option. If I do tail -f something.json | jq, jq will also format anything new added to the something.json file. If I pipe into jiq though, I never get anything at all. Not even the original content of the file.

My real use case is that I currently tail a log and send it into jq for formatting, which works fine, but I'd also like to be able to apply filters on the fly, instead of restarting jq all the time.

Does that make sense?

[fiatjaf]

Oh, I see it now. This seems complicated. I don't know how tail -f works, nor how jq does what it does. It doesn't seem to work if you modify an existing JSON object on the file, only if you add a new line, right?

Sorry, but I think I will not be able to include this feature anytime soon, but if you (or anyone else) did a PR I would be glad to merge it.

[SimenB]

Yes, just adding a new line. And logs are append only, so no real issue.

Ok, that's fine 😄

[fiatjaf]

It has something to do with reading Stdin as a stream, right? It shouldn't be difficult.

[SimenB]

Yup, sounds right.
I don't know Go at all, so won't be able to provide a PR, unfortunately.