[P2P] Initial libp2p integration

[bryanchriswhite]

Description

Adds a new P2P module implementation which wraps libp2p abstractions (mainly host.Host and pubsub.Pubsub) and adapts them to the current interfaces (modules.Module, types.Network, types.Transport).

Network Implementation

For "broadcast" messages (i.e. send to the network), the network implementation utilizes go-libp2p-pubsub to establish a publish / subscribe relationship between network nodes. A pubsub router implementation is used to determine which nodes to send which messages. For simplicity, this initial implementation uses the basic FloodSubRouter, which causes each node to contact every other node directly (i.e. fully-connected network); however, more sophisticated options are available, such as RandomSubRouter and GossipSubRouter.

For "direct" messages (i.e. send to specific node by identity), the network implementation opens a new stream to the desired peer, writes the network level message, establishing a connection to the peer if one does not already exist in the libp2p-managed connection pool, and then closes the stream. On the receiving side, peers watch for incoming streams on network start. When a new stream is opened by a remote peer, it's read from until EOF (i.e. stream closes) or until the read deadline times out.

Address Book

The network interface makes its API responsible for managing the address book (i.e. adding / removing peers). As this is encapsulated by the host.Host implementation in the libp2p regime, the new network implementation maintains a map of pocket peers by pocket "address", analogous to other network implementations; however, the pocket peers retrieved from this map are subsequently converted to their respective libp2p representations (peer.AddrInfo) for use by libp2p. The "pocket address book" is also updated when a remote peer opens a new stream, keeping it in sync with libp2p's.

Next Steps

1. Redefine P2P concrete types in terms of interfaces
   • PeersManager (raintree/peersManager)
   • Peer (p2p/types/NetworkPeer)
   • AddrBook (p2p/types/AddrBook)
   • AddrBookMap (p2p/types/NetworkPeer)
   • rainTreeNetwork shouldn't depend on any concrete p2p types
2. Simplify libp2p module implementation
   • The Transport interface likely reduces to nothing
   • The Network interface can be simplified
   • Consider renaming "network" as it functions more like a "router"
     (NB: could be replaced in future iterations with a "raintree pubsub router")
3. Remove "legacy" P2P module & rename libp2p module directory (possibly object names as well)
   • P2PModule interface can be simplified
   • Clean up TECHDEBT introduced in debug CLI and node startup

Issue

Relates to #347

Type of change

Please mark the relevant option(s):

• New feature, functionality or library
• Bug fix
• Code health or cleanup
• Major breaking change
• Documentation
• Other

List of changes

• Adds a new libp2p-based P2P modules.Module implementation in p2p/libp2p.
• Adds a new types.Network implemenation.
• Adds a new types.Transport.
• Adds new P2P config options:
  • use_lib_p2p to switch between the two P2P modules.
  • hostname to specify a registered name or IP address to listen on.

Testing

• make develop_test
• LocalNet w/ all of the steps outlined in the README

Required Checklist

• I have performed a self-review of my own code
• I have commented my code, particularly in hard-to-understand areas
• I have tested my changes using the available tooling
• I have updated the corresponding CHANGELOG

If Applicable Checklist

• I have updated the corresponding README(s); local and/or global
• I have added tests that prove my fix is effective or that my feature works
• I have added, or updated, mermaid.js diagrams in the corresponding README(s)
• I have added, or updated, documentation and mermaid.js diagrams in shared/docs/* if I updated shared/*README(s)

[bryanchriswhite]

Closing in preparation for splitting.