[Libp2p] Add Libp2p module (part 4) (#545)

## Description

This is another of a series of PRs split out from
#500. Here we add a new
`modules.P2PModule` implementation which utilizes the `typesP2P.Network`
implementation which was added in #540. It will be utilized together
with the config changes introduced by #535 in forthcoming changes to the
node and debug CLI.

## Issue

#347 

## Type of change

Please mark the relevant option(s):

- [x] New feature, functionality or library
- [ ] Bug fix
- [ ] Code health or cleanup
- [ ] Major breaking change
- [ ] Documentation
- [ ] Other <!-- add details here if it a different type of change -->

## List of changes

- Added a new `modules.P2PModule` implementation to the `libp2p` module
directory

## Testing

- [x] `make develop_test`
- [x]
[LocalNet](https://github.com/pokt-network/pocket/blob/main/docs/development/README.md)
w/ all of the steps outlined in the `README`

## Required Checklist

- [x] I have performed a self-review of my own code
- [x] I have commented my code, particularly in hard-to-understand areas
- [ ] I have tested my changes using the available tooling
- [x] 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](https://mermaid-js.github.io) diagrams in the corresponding
README(s)
- [ ] I have added, or updated, documentation and
[mermaid.js](https://mermaid-js.github.io) diagrams in `shared/docs/*`
if I updated `shared/*`README(s)

Author: bryanchriswhite

libp2p/docs/CHANGELOG.md

@@ -5,12 +5,16 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## [Unreleased]
 
+## [0.0.0.2] - 2023-03-03
+
+- Added a new `modules.P2PModule` implementation to the `libp2p` module directory
+
 ## [0.0.0.1] - 2023-03-03
 
 - Added a new `typesP2P.Network` implementation to the `libp2p` module directory
 - Added `PoktProtocolID` for use within the libp2p module or by public API consumers
 
-## [0.0.0.0] - 2023-03-01
+## [0.0.0.0] - 2023-02-23
 
 - prepare pocket repo new libp2p module
 - add pocket / libp2p identity helpers

libp2p/module.go

@@ -0,0 +1,374 @@
+/*
+TECHDEBT: This module currently imports types  from the "legacy" P2P module.
+
+Migration path:
+ 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 doesn't depend on any concrete p2p types
+ 2. Simplify libp2p module implementation
+    - Transport likely reduces to nothing
+    - 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
+*/
+package libp2p
+
+import (
+	"context"
+	"fmt"
+	"io"
+	"time"
+
+	"github.com/libp2p/go-libp2p"
+	pubsub "github.com/libp2p/go-libp2p-pubsub"
+	"github.com/libp2p/go-libp2p/core/host"
+	libp2pNetwork "github.com/libp2p/go-libp2p/core/network"
+	"github.com/multiformats/go-multiaddr"
+	"google.golang.org/protobuf/proto"
+	"google.golang.org/protobuf/types/known/anypb"
+
+	"github.com/pokt-network/pocket/libp2p/network"
+	"github.com/pokt-network/pocket/libp2p/protocol"
+	"github.com/pokt-network/pocket/logger"
+	typesP2P "github.com/pokt-network/pocket/p2p/types"
+	"github.com/pokt-network/pocket/runtime/configs"
+	"github.com/pokt-network/pocket/runtime/configs/types"
+	"github.com/pokt-network/pocket/shared/crypto"
+	"github.com/pokt-network/pocket/shared/messaging"
+	"github.com/pokt-network/pocket/shared/modules"
+	"github.com/pokt-network/pocket/shared/modules/base_modules"
+)
+
+var _ modules.P2PModule = &libp2pModule{}
+
+type libp2pModule struct {
+	base_modules.IntegratableModule
+
+	logger      *modules.Logger
+	cfg         *configs.P2PConfig
+	identity    libp2p.Option
+	listenAddrs libp2p.Option
+	// host encapsulates libp2p peerstore & connection manager
+	host host.Host
+	// pubsub is used for broadcast communication
+	// (i.e. multiple, unidentified receivers)
+	pubsub *pubsub.PubSub
+	// topic similar to pubsub but received messages are filtered by a "topic" string.
+	// Published messages are also given the respective topic before broadcast.
+	topic *pubsub.Topic
+	// subscription provides an interface to continuously read messages from.
+	subscription *pubsub.Subscription
+	network      typesP2P.Network
+}
+
+var (
+	// TECHDEBT: configure timeouts. Consider security exposure vs. real-world conditions).
+	// TECHDEBT: parameterize and expose via config.
+	// readStreamTimeout is the duration to wait for a read operation on a
+	// stream to complete, after which the stream is closed ("timed out").
+	readStreamTimeoutDuration = time.Second * 10
+)
+
+func Create(bus modules.Bus, options ...modules.ModuleOption) (modules.Module, error) {
+	return new(libp2pModule).Create(bus, options...)
+}
+
+func (mod *libp2pModule) GetModuleName() string {
+	return modules.P2PModuleName
+}
+
+func (_ *libp2pModule) Create(bus modules.Bus, options ...modules.ModuleOption) (modules.Module, error) {
+	logger.Global.Debug().Msg("Creating libp2p-backed network module")
+	mod := &libp2pModule{
+		cfg:    bus.GetRuntimeMgr().GetConfig().P2P,
+		logger: logger.Global.CreateLoggerForModule(modules.P2PModuleName),
+	}
+
+	// MUST call before referencing mod.bus to ensure != nil.
+	bus.RegisterModule(mod)
+
+	for _, option := range options {
+		option(mod)
+	}
+
+	// TECHDEBT: investigate any unnecessary
+	// key exposure / duplication in memory
+	privateKey, err := crypto.NewLibP2PPrivateKey(mod.cfg.PrivateKey)
+	if err != nil {
+		return nil, fmt.Errorf("loading private key: %w", err)
+	}
+
+	mod.identity = libp2p.Identity(privateKey)
+
+	// INCOMPLETE: support RainTree network
+	if mod.cfg.UseRainTree {
+		return nil, fmt.Errorf("%s", "raintree is not yet compatible with libp2p")
+	}
+
+	switch mod.cfg.ConnectionType {
+	case types.ConnectionType_TCPConnection:
+		addr, err := mod.getMultiaddr()
+		if err != nil {
+			return nil, fmt.Errorf("parsing multiaddr from config: %w", err)
+		}
+		mod.listenAddrs = libp2p.ListenAddrs(addr)
+	case types.ConnectionType_EmptyConnection:
+		mod.listenAddrs = libp2p.NoListenAddrs
+	default:
+		return nil, fmt.Errorf(
+			// DISCUSS: rename to "transport protocol" instead.
+			"unsupported connection type: %s: %w",
+			mod.cfg.ConnectionType,
+			err,
+		)
+	}
+
+	return mod, nil
+}
+
+func (mod *libp2pModule) Start() error {
+	// IMPROVE: receive context in interface methods.
+	ctx := context.Background()
+
+	// TECHDEBT: metrics integration.
+	var err error
+	opts := []libp2p.Option{
+		mod.identity,
+		// INCOMPLETE(#544): add transport security!
+	}
+
+	// Disable unused libp2p relay and ping services in client debug mode.
+	// (see: https://pkg.go.dev/github.com/libp2p/go-libp2p#DisableRelay
+	// and https://pkg.go.dev/github.com/libp2p/go-libp2p#Ping)
+	if mod.isClientDebugMode() {
+		opts = append(opts,
+			libp2p.DisableRelay(),
+			libp2p.Ping(false),
+			libp2p.NoListenAddrs,
+		)
+	} else {
+		opts = append(opts, mod.listenAddrs)
+	}
+
+	// Represents a libp2p network node, `libp2p.New` configures
+	// and starts listening according to options.
+	// (see: https://pkg.go.dev/github.com/libp2p/go-libp2p#section-readme)
+	mod.host, err = libp2p.New(opts...)
+	if err != nil {
+		return fmt.Errorf("unable to create libp2p host: %w", err)
+	}
+
+	listenAddrLogEvent := mod.logger.Info()
+	for i, addr := range host.InfoFromHost(mod.host).Addrs {
+		listenAddrLogEvent.Str(fmt.Sprintf("listen_addr_%d", i), addr.String())
+	}
+	listenAddrLogEvent.Msg("Listening for incoming connections...")
+
+	// TECHDEBT: use RandomSub or GossipSub once we're on more stable ground.
+	// IMPROVE: consider supporting multiple router types via config.
+	mod.pubsub, err = pubsub.NewFloodSub(ctx, mod.host)
+	if err != nil {
+		return fmt.Errorf("unable to create pubsub: %w", err)
+	}
+
+	// Topic is used to `#Publish` messages.
+	mod.topic, err = mod.pubsub.Join(protocol.DefaultTopicStr)
+	if err != nil {
+		return fmt.Errorf("unable to join pubsub topic: %w", err)
+	}
+
+	// Subscription is notified when a new message is received on the topic.
+	mod.subscription, err = mod.topic.Subscribe()
+	if err != nil {
+		return fmt.Errorf("subscribing to pubsub topic: %w", err)
+	}
+
+	mod.network, err = network.NewLibp2pNetwork(mod.GetBus(), mod.logger, mod.host, mod.topic)
+	if err != nil {
+		return fmt.Errorf("creating network: %w", err)
+	}
+
+	// Don't handle streams or read from the subscription in client debug mode.
+	if !mod.isClientDebugMode() {
+		mod.host.SetStreamHandler(protocol.PoktProtocolID, mod.handleStream)
+		go mod.readFromSubscription(ctx)
+	}
+	return nil
+}
+
+func (mod *libp2pModule) Stop() error {
+	return mod.host.Close()
+}
+
+func (mod *libp2pModule) Broadcast(msg *anypb.Any) error {
+	c := &messaging.PocketEnvelope{
+		Content: msg,
+	}
+	//TECHDEBT: use shared/codec for marshalling
+	data, err := proto.MarshalOptions{Deterministic: true}.Marshal(c)
+	if err != nil {
+		return err
+	}
+	mod.logger.Info().Msg("broadcasting message to network")
+
+	return mod.network.NetworkBroadcast(data)
+}
+
+func (mod *libp2pModule) Send(addr crypto.Address, msg *anypb.Any) error {
+	c := &messaging.PocketEnvelope{
+		Content: msg,
+	}
+	//TECHDEBT: use shared/codec for marshalling
+	data, err := proto.MarshalOptions{Deterministic: true}.Marshal(c)
+	if err != nil {
+		return err
+	}
+
+	return mod.network.NetworkSend(data, addr)
+}
+
+func (mod *libp2pModule) GetAddress() (crypto.Address, error) {
+	privateKey, err := crypto.NewPrivateKey(mod.cfg.PrivateKey)
+	if err != nil {
+		return nil, err
+	}
+
+	return privateKey.Address(), nil
+}
+
+// HandleEvent implements the respective `modules.Module` interface method.
+func (mod *libp2pModule) HandleEvent(msg *anypb.Any) error {
+	return nil
+}
+
+func (mod *libp2pModule) isClientDebugMode() bool {
+	return mod.GetBus().GetRuntimeMgr().GetConfig().ClientDebugMode
+}
+
+// handleStream is called each time a peer establishes a new stream with this
+// module's libp2p `host.Host`.
+func (mod *libp2pModule) handleStream(stream libp2pNetwork.Stream) {
+	peer, err := network.PeerFromLibp2pStream(stream)
+	if err != nil {
+		mod.logger.Error().Err(err).
+			Str("address", peer.Address.String()).
+			Msg("parsing remote peer public key")
+
+		if err = stream.Close(); err != nil {
+			mod.logger.Error().Err(err)
+		}
+	}
+
+	if err := mod.network.AddPeerToAddrBook(peer); err != nil {
+		mod.logger.Error().Err(err).
+			Str("address", peer.Address.String()).
+			Msg("adding remote peer to address book")
+	}
+
+	go mod.readStream(stream)
+}
+
+// readStream is intended to be called in a goroutine. It continuously reads from
+// the given stream for handling at the network level. Used for handling "direct"
+// messages (i.e. one specific target node).
+func (mod *libp2pModule) readStream(stream libp2pNetwork.Stream) {
+	closeStream := func() {
+		if err := stream.Close(); err != nil {
+			mod.logger.Error().Err(err)
+		}
+	}
+
+	// NB: time out if no data is sent to free resources.
+	if err := stream.SetReadDeadline(newReadStreamDeadline()); err != nil {
+		mod.logger.Error().Err(err).Msg("setting stream read deadline")
+		// TODO: abort if we can't set a read deadline?
+	}
+
+	data, err := io.ReadAll(stream)
+	if err != nil {
+		mod.logger.Error().Err(err).Msg("reading from stream")
+		closeStream()
+		// NB: abort this goroutine
+		// TODO: signal this somewhere?
+		return
+	}
+	defer closeStream()
+
+	mod.handleNetworkData(data)
+}
+
+// readFromSubscription is intended to be called in a goroutine. It continuously
+// reads from the subscribed topic in preparation for handling at the network level.
+// Used for handling "broadcast" messages (i.e. no specific target node).
+func (mod *libp2pModule) readFromSubscription(ctx context.Context) {
+	for {
+		select {
+		case <-ctx.Done():
+			return
+		default:
+			msg, err := mod.subscription.Next(ctx)
+			if err != nil {
+				mod.logger.Error().Err(err).
+					Bool("TODO", true).
+					Msg("reading from subscription")
+			}
+
+			// NB: ignore messages from self
+			if msg.ReceivedFrom == mod.host.ID() {
+				continue
+			}
+
+			mod.handleNetworkData(msg.Data)
+		}
+	}
+}
+
+func (mod *libp2pModule) handleNetworkData(data []byte) {
+	appMsgData, err := mod.network.HandleNetworkData(data)
+	if err != nil {
+		mod.logger.Error().Err(err).Msg("handling network data")
+		return
+	}
+
+	// There was no error, but we don't need to forward this to the app-specific bus.
+	// For example, the message has already been handled by the application.
+	if appMsgData == nil {
+		return
+	}
+
+	networkMessage := messaging.PocketEnvelope{}
+	if err := proto.Unmarshal(appMsgData, &networkMessage); err != nil {
+		mod.logger.Error().Err(err).
+			Bool("TODO", true).
+			Msg("Error decoding network message")
+		return
+	}
+
+	event := messaging.PocketEnvelope{
+		Content: networkMessage.Content,
+	}
+
+	mod.GetBus().PublishEventToBus(&event)
+}
+
+// getMultiaddr returns a multiaddr constructed from the `hostname` and `port`
+// in the P2P config which pas provided upon creation.
+func (mod *libp2pModule) getMultiaddr() (multiaddr.Multiaddr, error) {
+	// TECHDEBT: as soon as we add support for multiple transports
+	// (i.e. not just TCP), we'll need to do something else.
+	return network.Libp2pMultiaddrFromServiceURL(fmt.Sprintf(
+		"%s:%d", mod.cfg.Hostname, mod.cfg.Port,
+	))
+}
+
+// newReadStreamDeadline returns a future deadline
+// based on the read stream timeout duration.
+func newReadStreamDeadline() time.Time {
+	return time.Now().Add(readStreamTimeoutDuration)
+}