Logs

carlos logs is one timeline rather than two. Your app's own stdout and stderr come back interleaved with the platform's account of what happened to it — which instance woke and on what version, when something restarted it, and when a wake failed, with the reason.

carlos logs -app hello -since 1h

Lines print oldest to newest: a UTC timestamp, the stream, the instance, the message, and any structured fields your app attached, dimmed at the end.

Following

-f leaves the command running and polls for new lines every two seconds.

carlos logs -app hello -f

It runs close to live, not exactly live. Boxes ship what they have collected every ten seconds or so, so a follow arrives in small batches instead of scrolling a character at a time. Start one before a deploy and you will see the wake and the first requests.

Cutting it down

An hour of a busy app is more than anyone reads. -since takes a duration back from now (15m, 24h) or an RFC3339 timestamp, and -until closes the far end of the window. -grep matches an RE2 pattern against the message. -host narrows to a single instance when the app runs more than one. -n caps how many lines come back — a thousand by default, five thousand at most — and when the window has more than that, it tells you it is showing the newest.

There is also -stream. -stream app drops the platform's commentary and leaves your own output; -stream platform does the opposite.

The half you can't get any other way

Your app's output you could always have arranged for yourself. The platform stream is the part that needs a view from outside the process: instance woke (version a1b2c3), instance restarting (carlos restart), instance stopping, and — when a request got a 503 you cannot reproduce — a wake failure written in terms you can act on, like a socket left behind by a previous run, or nothing promoted on the channel this instance follows.

A static site has no process and so has no app stream at all. Its platform events still show up, and they are the reason to run carlos logs against a site.

How far back it goes

Seven days, and a size ceiling per app that drops the oldest hour first if an app is unusually chatty. If you need a longer record than that, have the app ship its own copy somewhere; the platform's retention is sized for debugging this week.

An empty result is usually honest, and worth a second look. Platform events only happen when something happens — a wake, a restart, a failure — so a quiet hour of a quiet app really does have nothing in it. Widen to -since 24h before you conclude that logging is broken.

The remaining flags, including -level and the repeatable -field, are in carlos logs.