Export wallet address for Prometheus metrics

[boojamya]

This adds the wallet address to the cosmos_relayer_wallet_balance and cosmos_relayer_fees_spent prometheus logs

[boojamya]

Closes: #1203

[DavidNix]

Yes! This is really close. Only 1 comment that needs addressing.

Prometheus requires label cardinality and label values to equal or else it panics. I think those look correct and I'm assuming some integration or e2e test would fail if not.

[DavidNix]

Are we sure it's safe to return here if we can't get the address?

This changes the control flow. If we error here, then line 225 go cc.waitForTx(asyncCtx, res.Hash, msgs, asyncTimeout, asyncCallback) never gets called.

This differs from the previous control flow that will always reach line 225.

We could log an error and continue as normal; only recording the metric if we get an address.

[boojamya]

I think the previous control flow does return an error prior to 225? line: 199 and 214.
Maybe I'm overlooking something.

Regardless, I like your idea of simply logging the the error rather than returning.

[DavidNix]

Line 199 and 214 do return an error and exit appropriately.

However, we're introducing a new error path if cc.Address() fails. cc.waitForTx will never be called if cc.Address() fails.

[boojamya]

Yes. I see. I mis-interpreted your first comment above.
Thanks for the explanations @DavidNix

[nourspace]

I wonder how we are using the same address in this loop. Is it supposed to be the same address for all iterations?

[boojamya]

Hmm, I'm not sure I full understand what you're saying.
It should however be noted that this metric will NOT be logged if somehow the wallet balance is exactly 0.

Maybe we should consider removing/altering this if statement...

[boojamya]

I adjusted this logic. See note below.

[nourspace]

I'm unfamiliar with how the relayer works, so I was wondering how we use the same address for different denoms.

[DavidNix]

style nit: Go convention is to use lower case for error messages. Also the comma is uncommon. I'm surprised a linter isn't catching this.

So

return fmt.Errorf("failed to get relayer bech32 wallet addresss: %w", err)

[DavidNix]

I also typically exclude "failed to" and other words because the error message, as it travels up the stack, often looks like:

failed to do X: error doing Y: failed to get Z

So I'd opt for this message:

return fmt.Errorf("get relayer bech32 wallet addresss: %w", err)

[boojamya]

Noted! Yea, this repo is fairly inconsistent with cap : /

Since we switched from returning to logging the error, I kept "failed..."

[boojamya]

The most rescent commit (702e084) ensures this metric gets logged EVEN IF the wallet has a 0 balance of the gas denom.

Note: if gas-prices in the relayer config are set to 0, for example gas-prices: 0ustake, than this metric will not be logged)