Add basic wallet functionality: check balance, unlock, transfer to external address

[kilrau]

Abstract

For our use case, the following API calls are missing, see specification.

Motivation

We want to be able to 1) check our on-chain balance and 2) unlock an ethereum keystore file 3) send on-chain funds to an external address. All directly through raiden, without dealing with another client (e.g. geth).

This is mainly to enable the user to stick with one keystore file/account managed solely by raiden. Using another client touching the keystore to e.g. transfer funds out on-chain causes severe issues (crashes) for raiden because the nonce counting gets messed up.

Specification

API calls:

1. check our own on-chain balance of ETH and token(s).
2. unlock a keystore file (not via password file, this is security-wise problematic: feat: create eth keystore with master seed ExchangeUnion/xud#1247 (review)), something like v1/api/unlock - { address: "...", password: "pswd" }
3. send on-chain ETH and Token(s) to an external address

*1) should be relatively easy to expose since functionality already exists.

Backwards Compatibility

It's new calls, I don't see a problem here.

[pirapira]

This sounds related to the "withdraw" feature that's currently being implemented #4130

[pirapira]

send on-chain ETH and Token(s) to an external address

should this "send"ing happen using Raiden, or a usual gas-eating transfer?

[kilrau]

on-chain, gas-eating, to an arbitrary external address

[pirapira]

Then that sounds exactly like the "withdraw".

[LefterisJP]

check our own on-chain balance of ETH and token(s).

Why does this need to happen through the Raiden API?
This is simple web3 calls to the ethereum chain.

send on-chain ETH and Token(s) to an external address

The only reason for this is since we need to do nonce counting inside Raiden, right?

[pirapira]

Ah, maybe I was mistaken. @kilrau is this issue about moving fund from a Raiden channel to somewhere?

[kilrau]

Why does this need to happen through the Raiden API?

Good point. Doesn't need to since the functionality is there via a L1 web3 call, like you said. It just would be nice. It's just more convenient for projects building on top of Raiden to not have to deal with API's of (differing) lower layer clients, like an ethereum full node. Checking wallet/account balance is IMHO an essential feature that probably most projects building on top of Raiden need at some point, so it would be nice to have it exposed directly through the Raiden API. Especially since Raiden has the functionality already:

Your account's balance is below the estimated gas reserve of 0.003573350023965722 eth. This may lead to a loss of of funds because your account will be unable to perform on-chain transactions. Please add funds to your account as soon as possible.

send on-chain ETH and Token(s) to an external address

The only reason for this is since we need to do nonce counting inside Raiden, right?
Ah, maybe I was mistaken. @kilrau is this issue about moving fund from a Raiden channel to somewhere?

Yes, because of nonce counting and also the same reason as above - abstracting from the lower layer client. And no, it's about sending tokens on-chain using gas to another external address on-chain. No channels involved at all. So if the withdrawal feature allows that (skimmed through the PR, but was a bit hard to find out if it only supports channel-related withdrawals), we are good here.

In summary do the two features above provide basic wallet functionality.

[rakanalh]

The only reason for this is since we need to do nonce counting inside Raiden, right?

Yes. Otherwise, Raiden will crash / behave inconsistently if the private key was used outside to perform a transaction on-chain to transfer funds or anything else for that matter.

I think that as long as the "private key should only be used by Raiden" rule stands, basic on-chain functions such as transferring ETH from one account to another should be provided by Raiden.

However, since this feature is "nice to have", then the priority of this needs to be determined.

[kilrau]

Also we noticed different kind of errors when we moved funds out of the raiden keystore file. Restarting raiden solved it. We should investigate the reason for this, and will details of the errors in the course of this issue.

[LefterisJP]

@kilrau If that happened while raiden was running this is a known issue. It has to do with the nonce handling.