P2P docs

p2p/README.md

@@ -1,35 +1,77 @@
-# P2P Module
+# `tendermint/p2p`
 
-P2P provides an abstraction around peer-to-peer communication.<br/>
-Communication happens via Reactors that react to messages from peers.<br/>
-Each Reactor has one or more Channels of communication for each Peer.<br/>
-Channels are multiplexed automatically and can be configured.<br/>
-A Switch is started upon app start, and handles Peer management.<br/>
-A PEXReactor implementation is provided to automate peer discovery.<br/>
+`tendermint/p2p` provides an abstraction around peer-to-peer communication.<br/>
 
-## Channels
+## Peer/MConnection/Channel
 
-Each peer connection is multiplexed into channels.
-The p2p module comes with a channel implementation used for peer
-discovery (called PEX, short for "peer exchange").
+Each peer has one `MConnection` (multiplex connection) instance.
 
-<table>
-  <tr>
-    <td><b>Channel</b></td>
-    <td>"PEX"</td>
-  </tr>
-  <tr>
-    <td><b>Messages</b></td>
-    <td>
-      <ul>
-        <li>pexRequestMsg</li>
-        <li>pexResponseMsg</li>
-      </ul>
-    </td>
-  </tr>
-</table>
-<hr />
+__multiplex__ *noun* a system or signal involving simultaneous transmission of
+several messages along a single channel of communication.
 
-## Resources
+Each `MConnection` handles message transmission on multiple abstract communication
+`Channel`s.  Each channel has a globally unique byte id.
+The byte id and the relative priorities of each `Channel` are configured upon
+initialization of the connection.
 
-* http://www.upnp-hacks.org/upnp.html
+There are two methods for sending messages:
+```go
+func (m MConnection) Send(chId byte, msg interface{}) bool {}
+func (m MConnection) TrySend(chId byte, msg interface{}) bool {}
+```
+
+`Send(chId, msg)` is a blocking call that waits until `msg` is successfully queued
+for the channel with the given id byte `chId`.  The message `msg` is serialized
+using the `tendermint/binary` submodule's `WriteBinary()` reflection routine.
+
+`TrySend(chId, msg)` is a nonblocking call that returns false if the channel's
+queue is full.
+
+`Send()` and `TrySend()` are also exposed for each `Peer`.
+
+## Switch/Reactor
+
+The `Switch` handles peer connections and exposes an API to receive incoming messages
+on `Reactors`.  Each `Reactor` is responsible for handling incoming messages of one
+or more `Channels`.  So while sending outgoing messages is typically performed on the peer,
+incoming messages are received on the reactor.
+
+```go
+// Declare a MyReactor reactor that handles messages on MyChannelId.
+type MyReactor struct{}
+
+func (reactor MyReactor) GetChannels() []*ChannelDescriptor {
+    return []*ChannelDescriptor{ChannelDescriptor{Id:MyChannelId, Priority: 1}}
+}
+
+func (reactor MyReactor) Receive(chId byte, peer *Peer, msgBytes []byte) {
+    r, n, err := bytes.NewBuffer(msgBytes), new(int64), new(error)
+    msgString := ReadString(r, n, err)
+    fmt.Println(msgString)
+}
+
+// Other Reactor methods omitted for brevity
+...
+
+switch := NewSwitch([]Reactor{MyReactor{}})
+
+...
+
+// Send a random message to all outbound connections
+for _, peer := range switch.Peers().List() {
+    if peer.IsOutbound() {
+        peer.Send(MyChannelId, "Here's a random message")
+    }
+}
+```
+
+### PexReactor/AddrBook
+
+A `PEXReactor` reactor implementation is provided to automate peer discovery.
+
+```go
+book := p2p.NewAddrBook(config.AddrBookFile())
+pexReactor := p2p.NewPEXReactor(book)
+...
+switch := NewSwitch([]Reactor{pexReactor, myReactor, ...})
+```

p2p/connection.go

@@ -34,8 +34,27 @@ type receiveCbFunc func(chId byte, msgBytes []byte)
 type errorCbFunc func(interface{})
 
 /*
-A MConnection wraps a network connection and handles buffering and multiplexing.
-<essages are sent with ".Send(channelId, msg)".
+Each peer has one `MConnection` (multiplex connection) instance.
+
+__multiplex__ *noun* a system or signal involving simultaneous transmission of
+several messages along a single channel of communication.
+
+Each `MConnection` handles message transmission on multiple abstract communication
+`Channel`s.  Each channel has a globally unique byte id.
+The byte id and the relative priorities of each `Channel` are configured upon
+initialization of the connection.
+
+There are two methods for sending messages:
+	func (m MConnection) Send(chId byte, msg interface{}) bool {}
+	func (m MConnection) TrySend(chId byte, msg interface{}) bool {}
+
+`Send(chId, msg)` is a blocking call that waits until `msg` is successfully queued
+for the channel with the given id byte `chId`.  The message `msg` is serialized
+using the `tendermint/binary` submodule's `WriteBinary()` reflection routine.
+
+`TrySend(chId, msg)` is a nonblocking call that returns false if the channel's
+queue is full.
+
 Inbound message bytes are handled with an onReceive callback function.
 */
 type MConnection struct {

p2p/listener.go

@@ -10,18 +10,13 @@ import (
 	"github.com/tendermint/tendermint/p2p/upnp"
 )
 
-/*
-Listener is part of a Server.
-*/
 type Listener interface {
 	Connections() <-chan net.Conn
 	ExternalAddress() *NetAddress
 	Stop()
 }
 
-/*
-DefaultListener is an implementation of Listener.
-*/
+// Implements Listener
 type DefaultListener struct {
 	listener    net.Listener
 	extAddr     *NetAddress

p2p/netaddress.go

@@ -11,8 +11,6 @@ import (
 	"time"
 )
 
-/* NetAddress */
-
 type NetAddress struct {
 	IP   net.IP
 	Port uint16

p2p/peer.go

@@ -10,8 +10,6 @@ import (
 	. "github.com/tendermint/tendermint/common"
 )
 
-/* Peer */
-
 type Peer struct {
 	outbound bool
 	mconn    *MConnection

p2p/peer_set.go

@@ -4,9 +4,7 @@ import (
 	"sync"
 )
 
-/*
-IPeerSet has a (immutable) subset of the methods of PeerSet.
-*/
+// IPeerSet has a (immutable) subset of the methods of PeerSet.
 type IPeerSet interface {
 	Has(key string) bool
 	List() []*Peer
@@ -15,10 +13,8 @@ type IPeerSet interface {
 
 //-----------------------------------------------------------------------------
 
-/*
-PeerSet is a special structure for keeping a table of peers.
-Iteration over the peers is super fast and thread-safe.
-*/
+// PeerSet is a special structure for keeping a table of peers.
+// Iteration over the peers is super fast and thread-safe.
 type PeerSet struct {
 	mtx    sync.Mutex
 	lookup map[string]*peerSetItem

p2p/switch.go

@@ -22,19 +22,10 @@ type Reactor interface {
 //-----------------------------------------------------------------------------
 
 /*
-All communication amongst peers are multiplexed by "channels".
-(Not the same as Go "channels")
-
-To send a message, serialize it into a ByteSlice and send it to each peer.
-For best performance, re-use the same immutable ByteSlice to each peer.
-You can also use a TypedBytes{} struct for convenience.
-You can find all connected and active peers by iterating over ".Peers().List()".
-".Broadcast()" is provided for convenience, but by iterating over
-the peers manually the caller can decide which subset receives a message.
-
-Inbound messages are received by calling ".Receive()".
-The receiver is responsible for decoding the message bytes, which may be preceded
-by a single type byte if a TypedBytes{} was used.
+The `Switch` handles peer connections and exposes an API to receive incoming messages
+on `Reactors`.  Each `Reactor` is responsible for handling incoming messages of one
+or more `Channels`.  So while sending outgoing messages is typically performed on the peer,
+incoming messages are received on the reactor.
 */
 type Switch struct {
 	reactors     []Reactor

p2p/upnp/README.md

@@ -0,0 +1,5 @@
+# `tendermint/p2p/upnp`
+
+## Resources
+
+* http://www.upnp-hacks.org/upnp.html