Recover original "swarm connect" behaviour with a flag

[hsanjuan]

Version information: master

Type: Enhancement

Description:

From 0.4.20 swarm connect tags connections with a harcoded weight of 100:

https://github.com/ipfs/go-ipfs/blob/master/core/coreapi/swarm.go#L31

This should indicate the ConnManager that those connections should be kept alive (although it may not work #6271 ). That happens around here:

https://github.com/libp2p/go-libp2p-connmgr/blob/master/connmgr.go#L157

where peers are sorted based on the value resulting from the sum of their tags.

There should be a way (an extra flag for example) to just swarm connect normally to a peer like it happened before. The idea is tha swarm connect can be used to bootstrap the swarm but does not necessarily mean that the connected peer should have priority over any others when it comes to disposing of connections. Or at least the weight should be selectable by the user.

I was going to do this but it seems to require changes to coreapi (to pass tags/weights), so better discuss before.

[Stebalien]

I'd also be happy to make setting a weight a flag.

[hsanjuan]

We can either extend the Connect core api method to take a weight, or we could start carrying connmgr tags in PeerInfos objects (which doesn't sound completely out of place at least, given that connmgr tags are peer information in end)...

[Stebalien]

We can also just tag outside the CoreAPI manually (until we come up with a nice API for this). Alternatively, allowing options is probably sane. We can then just make this:

ipfs swarm connect --tag myservice=50 --tag other=2