`nelm release install` with `--auto-rollback` should rollback on SIGINT, SIGTERM

[pznamensky]

Before proceeding

• I didn't find a similar issue

Version

werf 2.6.0

How to reproduce

1. Run an upgrade for any chart using --atomic flag: werf helm upgrade --install some-chart --atomic -f values.yaml
2. Press Ctrl+C (or send SIGINT signal)

Result

Werf will print "Release my-release has been cancelled" and the chart will remain in "pending-*" state.
You can check it like this: helm ls -a

Expected result

The release will be rolled back due --atomic is set.

Additional information

This is how helm works:

^CRelease my-release has been cancelled.
Error: release my-release failed, and has been uninstalled due to atomic being set: context canceled

It would be great if werf could work the same way there.

[pznamensky]

Just wanted to note that this is quite important in workflows where a werf is invoked from CI/CD, as after cancelling a deployment you need to manually resolve an issue with a pending release.
Usually that's quite inconvenient as the needed access to k8s cluster can only have a limited number of people.

[ilya-lesikov]

In a few months we will release Nelm (our new deployment engine for werf) as a standalone utility. Nelm will be the Helm 3 replacement, making werf helm obsolete. If everything goes right we plan on removing werf helm afterwards, probably in werf 3.0.

Nelm and werf converge have their own release locking system, which does not rely on the last release status (pending), like Helm. So if nelm/werf is killed, then the lock will be automatically released in a few seconds.

[pznamensky]

Awesome, thank you.

[ilya-lesikov]

Nelm 1.0 released. Release in a pending-* state doesn't block further nelm release install or werf converge. Yet we still need to capture INT, TERM signals and proceed to the rollback, if enabled. Second INT, TERM must stop the rollback.

[pznamensky]

I've noticed that rollback seems to be working as expected in werf helm ... now, so I just thought that it might be possible to cherry pick the fix from werf. If that make sense of course.

[ilya-lesikov]

At this point werf helm and werf converge/nelm release install share only like half of the codebase. We haven't updated werf helm in quite a while. The plan is to remove werf helm in the next major in favor of just using nelm binary if you don't want the extra things that come with werf (image building, giterminism, ...).