Hermes feature: Query the balance for a key

[andynog]

Crate

ibc-relayer-cli

Summary

It would be nice to be able to query a balance for a key used in the relayer directly from hermes

Problem Definition

A user needs to track the balance remaining in a account (for a key) configured in the relayer. This will make it easier to know when you need to add more funds to the key or even switch to a different account that has enough funds to submit transactions.

Proposal

Implement a command such as keys balance [chain-id] [keyname]. This probably can be accomplished using a GRPC call to the bank module.

Acceptance Criteria

The balance for the account associated with the key is returned.

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[ljoss17]

I'm looking at this issue and stumbled upon a detail which could be interesting for future improvement of this feature.
At the moment, it is possible to query the balance using the CosmosSdkChain method query_balance, but this will query the balance of the gas price denom only, which is defined inside the config file.
Since the main interest is to be able to see if there are enough funds to pay the transaction, this shouldn't be a problem at the moment. But might it be useful to be able to list all the balances associated to a key in a future improvement ?