setupAccount's implementation differs from the spec

[georgeroman]

The implementation of the setupAccount action differs from the official specification (https://github.com/interledger/rfcs/blob/master/0038-settlement-engines/0038-settlement-engines.md#setup-an-account). Here are the differences:

• the specification doesn't say anything about passing an empty settlement account id, but here an account id is automatically generated if none is passed
• the specification doesn't say anything about returning the settlement account id back to the connector (it only requires a 201 status code in case of success), but here the account id is returned as well (of course, this is to make the connector aware of the settlement account id generated by the settlement engine)

I'm not sure which is the correct way to implement the setup account action. It looks like interledger-rs works fine with following the official specs but ilpv4-connector doesn't and requires the extra steps.

Here is the setupAccount implementation:

settlement-core/src/controllers.ts

Lines 30 to 60 in b261b51

	setupAccount: async (req, res) => {
	const accountId = req.body.id || uuid() // Create account ID if none was provided
	if (!isSafeKey(accountId)) {
	return res.status(400).send('Account ID includes unsafe characters')
	}
	/**
	* TODO
	* Before creating the accout/calling setup, ensure the peer is reachable:
	* Try pinging them and await either a response or a ping from said peer
	*/
	try {
	await store.createAccount(accountId)
	} catch (err) {
	log(`Failed to setup account: account=${accountId}`, err)
	return res.sendStatus(500)
	}
	if (engine.setupAccount) {
	try {
	await engine.setupAccount(accountId) // TODO Is it safe if this is called multiple times?
	} catch (err) {
	log(`Failed to setup account: account=${accountId}`, err)
	return res.sendStatus(500)
	}
	}
	res.status(201).send({
	id: accountId
	})