Add shutdown hook

[planetf1]

Is there an existing issue for this?

• [X] I have searched the existing issues

Please describe the new behavior that that will improve Egeria

Add a shutdown hook for Egeria, specifically to handle SIGTERM

In operational environments the system/container/process running an Egeria platform may need to be shutdown externally - a system restart, or Kubernetes killing a pod.

These systems are not aware of Egeria APIs, and will typically send a SIGTERM to the jvm, wait about 30s, and then send a SIGKILL (which cannot be handled/blocked)

Egeria should register a shutdown hook, and on received of a SIGTERM or similar, should do what we can to clean down sufficiently cleanly, for a temporary stop. For example this might include attempting to commit the appropriate Kafka offsets, but also it gives opportunity to do other things, for example it may be possible to call connectors to stop - however timescales are short, and we need to take care with any blocking calls.

This may improve resilience/restart time.

Currently the SIGTERM will directly kill the vm - which does of course work

Alternatives

Currently the SIGTERM will directly kill the vm - which does of course work. We may decide this is sufficient

Any Further Information?

No response

Would you be prepared to be assigned this issue to work on?

• [X] I can work on this

[planetf1]

Came across these options which may be part of the picture -- this will give the spring application 30s to shut down.

It may be we just do this in demos/charts, but would also want to test/document & understand the shutdown behaviour

[planetf1]

Adding container label, as in a dynamic k8s environment, scaling operations may mean this is more important, to ensure our integrity

[github-actions[bot]]

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