p2p: force direct connections

[xenowits]

Force direct connection when there is an existing relay connection to the peer.

category: feature
ticket: #2114

[codecov]

Codecov Report

Patch coverage has no change and project coverage change: +0.15 🎉

Comparison is base (b3d0ba0) 53.67% compared to head (3467bbd) 53.82%.

❗ Current head 3467bbd differs from pull request most recent head 08ad13d. Consider uploading reports for the commit 08ad13d to get more accurate results

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #2222      +/-   ##
==========================================
+ Coverage   53.67%   53.82%   +0.15%     
==========================================
  Files         186      187       +1     
  Lines       24345    24965     +620     
==========================================
+ Hits        13066    13438     +372     
- Misses       9657     9876     +219     
- Partials     1622     1651      +29     

Impacted Files	Coverage Δ
app/app.go	6.72% <0.00%> (-0.03%)	⬇️
app/lifecycle/orderstart_string.go	40.00% <ø> (ø)
cmd/relay/p2p.go	38.46% <ø> (ø)
p2p/p2p.go	22.54% <0.00%> (-3.29%)	⬇️

... and 16 files with indirect coverage changes

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[xenowits]

Screenshot of a compose run:

[OisinKyne]

Can we write a hypothesis here to test this? e.g. how many situations do we end up stuck, and how often does the 'force' succeed? Are there any negative consequences of this?

[xenowits]

We tested this in prod starting with the core team cluster. It has a success rate of 100% for forced direct connections, you're never stuck. This force feature is not an exotic thing we do, libp2p does this a lot under the hood.

AFAIK, there are no negative consequences for this. But as with any new feature, we need to monitor this feature in production clusters from release v0.16.0