eth, p2p, rpc/api: polish protocol info gathering

p2p/peer.go

@@ -359,3 +359,49 @@ func (rw *protoRW) ReadMsg() (Msg, error) {
 		return Msg{}, io.EOF
 	}
 }
+
+// PeerInfo represents a short summary of the information known about a connected
+// peer. Sub-protocol independent fields are contained and initialized here, with
+// protocol specifics delegated to all connected sub-protocols.
+type PeerInfo struct {
+	ID      string   `json:"id"`   // Unique node identifier (also the encryption key)
+	Name    string   `json:"name"` // Name of the node, including client type, version, OS, custom data
+	Caps    []string `json:"caps"` // Sum-protocols advertised by this particular peer
+	Network struct {
+		LocalAddress  string `json:"localAddress"`  // Local endpoint of the TCP data connection
+		RemoteAddress string `json:"remoteAddress"` // Remote endpoint of the TCP data connection
+	} `json:"network"`
+	Protocols map[string]interface{} `json:"protocols"` // Sub-protocol specific metadata fields
+}
+
+// Info gathers and returns a collection of metadata known about a peer.
+func (p *Peer) Info() *PeerInfo {
+	// Gather the protocol capabilities
+	var caps []string
+	for _, cap := range p.Caps() {
+		caps = append(caps, cap.String())
+	}
+	// Assemble the generic peer metadata
+	info := &PeerInfo{
+		ID:        p.ID().String(),
+		Name:      p.Name(),
+		Caps:      caps,
+		Protocols: make(map[string]interface{}),
+	}
+	info.Network.LocalAddress = p.LocalAddr().String()
+	info.Network.RemoteAddress = p.RemoteAddr().String()
+
+	// Gather all the running protocol infos
+	for _, proto := range p.running {
+		protoInfo := interface{}("unknown")
+		if query := proto.Protocol.PeerInfo; query != nil {
+			if metadata := query(p.ID()); metadata != nil {
+				protoInfo = metadata
+			} else {
+				protoInfo = "handshake"
+			}
+		}
+		info.Protocols[proto.Name] = protoInfo
+	}
+	return info
+}

p2p/protocol.go

@@ -16,7 +16,11 @@
 
 package p2p
 
-import "fmt"
+import (
+	"fmt"
+
+	"github.com/ethereum/go-ethereum/p2p/discover"
+)
 
 // Protocol represents a P2P subprotocol implementation.
 type Protocol struct {
@@ -39,6 +43,15 @@ type Protocol struct {
 	// any protocol-level error (such as an I/O error) that is
 	// encountered.
 	Run func(peer *Peer, rw MsgReadWriter) error
+
+	// NodeInfo is an optional helper method to retrieve protocol specific metadata
+	// about the host node.
+	NodeInfo func() interface{}
+
+	// PeerInfo is an optional helper method to retrieve protocol specific metadata
+	// about a certain peer in the network. If an info retrieval function is set,
+	// but returns nil, it is assumed that the protocol handshake is still running.
+	PeerInfo func(id discover.NodeID) interface{}
 }
 
 func (p Protocol) cap() Cap {

p2p/server.go

@@ -689,3 +689,66 @@ func (srv *Server) runPeer(p *Peer) {
 		NumConnections: srv.PeerCount(),
 	})
 }
+
+// NodeInfo represents a short summary of the information known about the host.
+type NodeInfo struct {
+	ID    string `json:"id"`    // Unique node identifier (also the encryption key)
+	Name  string `json:"name"`  // Name of the node, including client type, version, OS, custom data
+	Enode string `json:"enode"` // Enode URL for adding this peer from remote peers
+	IP    string `json:"ip"`    // IP address of the node
+	Ports struct {
+		Discovery int `json:"discovery"` // UDP listening port for discovery protocol
+		Listener  int `json:"listener"`  // TCP listening port for RLPx
+	} `json:"ports"`
+	ListenAddr string                 `json:"listenAddr"`
+	Protocols  map[string]interface{} `json:"protocols"`
+}
+
+// Info gathers and returns a collection of metadata known about the host.
+func (srv *Server) NodeInfo() *NodeInfo {
+	node := srv.Self()
+
+	// Gather and assemble the generic node infos
+	info := &NodeInfo{
+		Name:       srv.Name,
+		Enode:      node.String(),
+		ID:         node.ID.String(),
+		IP:         node.IP.String(),
+		ListenAddr: srv.ListenAddr,
+		Protocols:  make(map[string]interface{}),
+	}
+	info.Ports.Discovery = int(node.UDP)
+	info.Ports.Listener = int(node.TCP)
+
+	// Gather all the running protocol infos (only once per protocol type)
+	for _, proto := range srv.Protocols {
+		if _, ok := info.Protocols[proto.Name]; !ok {
+			nodeInfo := interface{}("unknown")
+			if query := proto.NodeInfo; query != nil {
+				nodeInfo = proto.NodeInfo()
+			}
+			info.Protocols[proto.Name] = nodeInfo
+		}
+	}
+	return info
+}
+
+// PeersInfo returns an array of metadata objects describing connected peers.
+func (srv *Server) PeersInfo() []*PeerInfo {
+	// Gather all the generic and sub-protocol specific infos
+	infos := make([]*PeerInfo, 0, srv.PeerCount())
+	for _, peer := range srv.Peers() {
+		if peer != nil {
+			infos = append(infos, peer.Info())
+		}
+	}
+	// Sort the result array alphabetically by node identifier
+	for i := 0; i < len(infos); i++ {
+		for j := i + 1; j < len(infos); j++ {
+			if infos[i].ID > infos[j].ID {
+				infos[i], infos[j] = infos[j], infos[i]
+			}
+		}
+	}
+	return infos
+}