Package peer provides a common base for creating and managing network peers.
This package has intentionally been designed so it can be used as a standalone package for any projects needing a full featured soter peer base to build on.
This package builds upon the wire package, which provides the fundamental
primitives necessary to speak the soter wire protocol, in order to simplify
the process of creating fully functional peers. In essence, it provides a
common base for creating concurrent safe fully validating nodes, Simplified
Payment Verification (SPV) nodes, proxies, etc.
A quick overview of the major features peer provides are as follows:
- Provides a basic concurrent safe soter peer for handling soter communications via the peer-to-peer protocol
- Full duplex reading and writing of soter protocol messages
- Automatic handling of the initial handshake process including protocol version negotiation
- Asynchronous message queueing of outbound messages with optional channel for notification when the message is actually sent
- Flexible peer configuration
- Caller is responsible for creating outgoing connections and listening for incoming connections so they have flexibility to establish connections as they see fit (proxies, etc)
- User agent name and version
- soter network
- Service support signalling (full nodes, bloom filters, etc)
- Maximum supported protocol version
- Ability to register callbacks for handling soter protocol messages
- Inventory message batching and send trickling with known inventory detection and avoidance
- Automatic periodic keep-alive pinging and pong responses
- Random nonce generation and self connection detection
- Proper handling of bloom filter related commands when the caller does not
specify the related flag to signal support
- Disconnects the peer when the protocol version is high enough
- Does not invoke the related callbacks for older protocol versions
- Snapshottable peer statistics such as the total number of bytes read and written, the remote address, user agent, and negotiated protocol version
- Helper functions pushing addresses, getblocks, getheaders, and reject
messages
- These could all be sent manually via the standard message output function, but the helpers provide additional nice functionality such as duplicate filtering and address randomization
- Ability to wait for shutdown/disconnect
- Comprehensive test coverage
While soterd implements soter p2p protocol and an RPC protocol with overlapping functionality, soterd only exchanges blocks with peers via the p2p protocol.
$ go get -u github.com/soteria-dag/soterd/peerThis example demonstrates the basic process for initializing and creating an outbound peer. Peers negotiate by exchanging version and verack messages. For demonstration, a simple handler for the version message is attached to the peer.
package main
import (
"fmt"
"net"
"time"
"github.com/soteria-dag/soterd/chaincfg"
"github.com/soteria-dag/soterd/peer"
"github.com/soteria-dag/soterd/wire"
)
// mockRemotePeer creates a basic inbound peer listening on the simnet port for
// use with Example_peerConnection. It does not return until the listner is
// active.
func mockRemotePeer() error {
// Configure peer to act as a simnet node that offers no services.
peerCfg := &peer.Config{
UserAgentName: "peer", // User agent name to advertise.
UserAgentVersion: "1.0.0", // User agent version to advertise.
ChainParams: &chaincfg.SimNetParams,
TrickleInterval: time.Second * 10,
}
// Accept connections on the simnet port.
listener, err := net.Listen("tcp", "127.0.0.1:18555")
if err != nil {
return err
}
go func() {
conn, err := listener.Accept()
if err != nil {
fmt.Printf("Accept: error %v\n", err)
return
}
// Create and start the inbound peer.
p := peer.NewInboundPeer(peerCfg)
p.AssociateConnection(conn)
}()
return nil
}
// This example demonstrates the basic process for initializing and creating an
// outbound peer. Peers negotiate by exchanging version and verack messages.
// For demonstration, a simple handler for version message is attached to the
// peer.
func main() {
// Ordinarily this will not be needed since the outbound peer will be
// connecting to a remote peer, however, since this example is executed
// and tested, a mock remote peer is needed to listen for the outbound
// peer.
if err := mockRemotePeer(); err != nil {
fmt.Printf("mockRemotePeer: unexpected error %v\n", err)
return
}
// Create an outbound peer that is configured to act as a simnet node
// that offers no services and has listeners for the version and verack
// messages. The verack listener is used here to signal the code below
// when the handshake has been finished by signalling a channel.
verack := make(chan struct{})
peerCfg := &peer.Config{
UserAgentName: "peer", // User agent name to advertise.
UserAgentVersion: "1.0.0", // User agent version to advertise.
ChainParams: &chaincfg.SimNetParams,
Services: 0,
TrickleInterval: time.Second * 10,
Listeners: peer.MessageListeners{
OnVersion: func(p *peer.Peer, msg *wire.MsgVersion) {
fmt.Println("outbound: received version")
},
OnVerAck: func(p *peer.Peer, msg *wire.MsgVerAck) {
verack <- struct{}{}
},
},
}
p, err := peer.NewOutboundPeer(peerCfg, "127.0.0.1:18555")
if err != nil {
fmt.Printf("NewOutboundPeer: error %v\n", err)
return
}
// Establish the connection to the peer address and mark it connected.
conn, err := net.Dial("tcp", p.Addr())
if err != nil {
fmt.Printf("net.Dial: error %v\n", err)
return
}
p.AssociateConnection(conn)
// Wait for the verack message or timeout in case of failure.
select {
case <-verack:
case <-time.After(time.Second * 1):
fmt.Printf("Example_peerConnection: verack timeout")
}
// Disconnect the peer.
p.Disconnect()
p.WaitForDisconnect()
}Package peer is licensed under the copyfree ISC License.