perf: set sync-timeout

[jumpeiMano]

Edit: Resolves #3278

I modified sync.go to use SyncTimeout in Daemon.Sync function.
Because sometimes I have saw errors like this.

caller=loop.go:108 component=sync-loop err="loading resources from repo: 
error executing generator command \"kustomize build .\" from file \".flux.yaml\": context deadline exceeded
error output:
generated output:\n"

[jumpeiMano]

@squaremo @stefanprodan Cloud you please check this PR? 🙇

[yebyen]

Hi @jumpeiMano I wonder if you can elaborate on why this change is needed? I see you've provided some context already.

What is timing out, or is there a point at which the timeout was not being honored that this change fixes? How does this fix it? Could we add a test that shows how it was failing before, or can we give some explanation for why this change is needed?

Flux v1 is in maintenance mode, but I'm sure if this fixes something important it can be included in a next release soon!

[jumpeiMano]

@yebyen Thank you for your comment!

why this change is needed?

I am using the patchUpdated feature of flux v1. The command I have written in the .flux.yaml is below:

ls -d */ | xargs -I % sh -c 'echo ---; kustomize build %;'

This kustomize build command's result is sometimes huge. Often, there is a timeout error here, as described in the description.

In flux v1, there are some timeout-related flags, like git-timeout and sync-timeout, but neither of these flags are applied to this command execution, and the default context created by context.Background() is used, I have no way to extend the timeout value. Therefore, I have now made a fix so that the sync-timeout value is adopted in the Sync() function.

[kingdonb]

Hi, I'd really like to include this in 1.22.0 if it solves some weird timeout situations.

Can you add your --sign-off to the commit with

git commit --amend --signoff

and

git push --force-with-lease origin set-sync-timeout

per the details posted through DCO bot in the checks?

No need to rebase, as I will rebase anyway into #3442,
I should be able to force push into this branch, (but I cannot add your sign-off.)

[jumpeiMano]

@kingdonb Thank you for your reviewing! Done!! d0ff266

[yebyen]

I think this resolves #3372

We should be able to test and close both of these in Flux 1.23.0, it may turn out to take a couple of weeks more, past the milestone assigned date though.

[kingdonb]

I'm planning on merging this right after #3250 and cutting a release 1.22.2 that will include this change today.

[kingdonb]

LGTM

[kingdonb]

This PR may have caused an issue that is reported in #3500

If there is any insight you can provide, or an updated/different PR that does not cause the reported ephemeral storage growth issue (unbounded) when timeout is engaging, it would be preferable to fix forward than to simply revert the PR.

@jumpeiMano Do you mind taking a look at this issue, and letting me know if you can confirm the details reported there?

It appears this was a red herring, the culprit is most likely an upgrade to Kustomize.