Support kickstarting swaps

[lukechilds]

https://modulelab.slack.com/archives/C8ADPSWTB/p1525328006000031

Sindre Sorhus [1:13 PM]
@Luke Childs https://github.com/jl777/SuperNET/commit/8725909b3c12f8df17de0b075422ad3676cc5195 

Have you thought about how the kickstart thing will work? I assume it's just a temporary workaround until mm does this automatically?

Luke Childs [1:14 PM]
no we’ll need kickstart long term
so if they quit the app with pending trades
or in process trades
then restart
we need to filter all the in progress trades and tell mm to resume them
I think it will be a fair bit of work to integrate
mm will most likely give us no helpful feedback in the event that:
- the trade doesn’t exist 
- exists but can’t be restarted
- was already automatically restarted
- is in the progress of being rolled back (edited)
we need to handle all those cases
and we probably won’t get enough information to
and we also need to re-attach event listeners so we get socket updates on restarted trades
if mm auto restarts them without telling us we’ll miss them
so many things that can go wrong
this is exactly why we shouldn’t have two separate swap DB instances…
😞
For v2 we need to push for a built in swap DB in mm that actually works and scales
so we have no internal copy
we just query mm as the single source of truth
They could use sqlite or LevelDB or something light weight

[lukechilds]

Related:

• Kickstart stuck swap lukechilds/hyperdex-bugtracker#1
• swap status stuck on 'Pending' for hours lukechilds/hyperdex-bugtracker#10
• Swap status stays "pending" if application is interrupted by machine sleep lukechilds/hyperdex-bugtracker#16
• Swaps stuck as pending jl777/SuperNET#775

[lukechilds]

Just saving this snippet here for future reference:

_swapDB._getSwapData('f8b3d902d9c21ed0a2231ade8965f6f710d04953c27f00156e9a346550de1b20')
	.then(data => data.messages.reduce((ids, msg) => {
		ids.requestid = msg.requestid || ids.requestid;
		ids.quoteid = msg.quoteid || ids.quoteid;
		return ids;
	}, {}))
	.then(ids => {
		console.log(ids);
		_api.debug({method: 'kickstart', ...ids});
	});

[lukechilds]

This behaviour is too unreliable right now and doesn't appear to be as important as we first thought:

kickstart can only make progress if progress is possible. likely you need to wait the 4hrs and unless the .finished file was created in error, kickstart wont be needed

lukechilds/hyperdex-bugtracker#1 (comment)

There's no way for us to reliably know if a kickstart is needed and or if it has been successful.