Should be possible to set an actual revision timeout (max duration, not first byte)

[julz]

/area API

Describe the feature

The revision spec.TimeoutSeconds feature was changed at some point to only be a timeout until the first byte of the response is sent. This is useful for WebSocket apps because it avoids timing out idle long running websockets. Unfortunately it defeats quite a lot of the point of a timeout because it doesn't stop requests running for an arbitrarily long time. This makes it hard to ensure it's safe to drain a node or avoid infinite-looping requests costing money for unbounded periods (absent a liveness check, anyway).

We should add a MaxDurationSeconds field to the spec to limit the actual max duration a request can run. This would be useful for users and operators who want to set an actual max duration a request/function can run. To avoid problems with websockets this would be an optional field defaulting to 0=infinity.

[evankanderson]

Is this separate from #10852? The two seem related/duplicate.

If we're updating the timeout lifecycle, it seems like it would be reasonable to have one issue to track both knobs.

/triage needs-user-input

[julz]

I think they're two separate features. One is an idle timeout, one is the maximum length of a "function"/request. It's easy to imagine us only implementing/prioritising one or the other, and I definitely think a PR that did both at once would be too big.

[github-actions]

This issue is stale because it has been open for 90 days with no
activity. It will automatically close after 30 more days of
inactivity. Reopen the issue with /reopen. Mark the issue as
fresh by adding the comment /remove-lifecycle stale.

[julz]

/remove-lifecycle stale

I still think this is good, I just didn’t get to it yet

[evankanderson]

I'm going to guess here:

/good-first-issue
/help

/remove-triage needs-user-input
/triage accepted

[knative-prow-robot]

@evankanderson:
This request has been marked as suitable for new contributors.

Please ensure the request meets the requirements listed here.

If this request no longer meets these requirements, the label can be removed
by commenting with the /remove-good-first-issue command.

In response to this:

I'm going to guess here:

/good-first-issue
/help

/remove-triage needs-user-input
/triage accepted

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[skonto]

@julz you mind if I work on this?

[julz]

not at all!

/assign @dprotaso to make sure you're ok with the api (tldr a MaxDurationSeconds field which is the actual max request length, not just time to first byte).

/assign @skonto

[dprotaso]

Yeah 👍

[skonto]

Back to this, now that idle timeout final piece is close to merge.