Add `--exit-epoch` flag to validator-manager

[xenowits]

Description

This is a feature request to add an --exit-epoch flag to the lighthouse account validator exit command.

This feature allows the user to set a specific epoch for the voluntary exit. It is supported by other validator clients such as teku, lodestar and nimbus.

Version

None.

Present Behaviour

Currently, a user can't specify the desired epoch to exit and the lighthouse VC broadcasts exit message with the current epoch.

Expected Behaviour

The validator client should allow a user to set a desired exit epoch.

Steps to resolve

• Add a new flag --exit-epoch to https://github.com/sigp/lighthouse/blob/stable/account_manager/src/validator/exit.rs.
• Modify publish_voluntary_exit() function to use the epoch provided above (if any).

[michaelsproul]

@xenowits As a workaround, try using the keymanager API for exits: https://ethereum.github.io/keymanager-APIs/?urls.primaryName=dev#/Voluntary%20Exit/signVoluntaryExit

Info on setting up the Lighthouse VC API can be found here: https://lighthouse-book.sigmaprime.io/api-vc.html

[michaelsproul]

This may also be already implemented by https://github.com/sigp/lighthouse/pull/3502, I'm not sure.

[xenowits]

This may also be already implemented by https://github.com/sigp/lighthouse/pull/3502, I'm not sure.

Thanks for the workaround!

But, do you think it is feasible to introduce this feature or are there some limitations?

[michaelsproul]

@xenowits It's definitely feasible. The lighthouse validator-manager is a new CLI that uses the API, so it would be super easy to include it there. We could also add it to the existing CLI easily enough, but would probably move people towards the validator-manager long term.

[xenowits]

okay, so the validator-manager is a new CLI feature that is not yet released i suppose?

Yeah, this subcommand would be cool to use for exits then 👍

[xenowits]

@michaelsproul is the lighthouse validator-manager command released?

[michaelsproul]

No, not yet. The PR hasn't merged to unstable yet

[chong-he]

Specifying --exit-epoch is now available using the lighthouse vm exit command: https://lighthouse-book.sigmaprime.io/validator_manager_api.html#exit

Added in #6612