Add "debug connect" command.

Command Debug.go

@@ -0,0 +1,93 @@
+/*
+File Name:  Command Debug.go
+Copyright:  2021 Peernet Foundation s.r.o.
+Author:     Peter Kleissner
+*/
+
+package main
+
+import (
+	"encoding/hex"
+	"fmt"
+	"sync"
+	"time"
+
+	"github.com/PeernetOfficial/core"
+	"github.com/PeernetOfficial/core/dht"
+)
+
+// debugCmdConnect connects to the node ID
+func debugCmdConnect(nodeID []byte) {
+	fmt.Printf("---------------- Connect to node %s ----------------\n", hex.EncodeToString(nodeID))
+	defer fmt.Printf("---------------- done node %s ----------------\n", hex.EncodeToString(nodeID))
+
+	// in local DHT list?
+	_, peer := core.IsNodeContact(nodeID)
+	if peer != nil {
+		fmt.Printf("* In local routing table: Yes.\n")
+	} else {
+		fmt.Printf("* In local routing table: No. Lookup via DHT. Timeout = 10 seconds.\n")
+
+		addKeyMonitor(nodeID)
+		defer removeKeyMonitor(nodeID)
+
+		// Discovery via DHT.
+		_, peer, _ = core.FindNode(nodeID, time.Second*10)
+		if peer == nil {
+			fmt.Printf("Not found via DHT :(\n")
+			return
+		}
+
+		fmt.Printf("Successfully discovered via DHT.\n")
+	}
+
+	// virtual peer?
+	if peer.IsVirtual() {
+		fmt.Printf("* Peer is virtual and was not contacted before. It will show no active connections until contacted.\n")
+	}
+
+	fmt.Printf("* Peer details:\n")
+	fmt.Printf("%s", textPeerConnections(peer))
+
+	// ping via all connections TODO
+	//fmt.Printf("* Sending ping:\n")
+}
+
+// debug output of monitored keys searched in the DHT
+
+var monitorKeys map[string]struct{}
+var monitorKeysMutex sync.RWMutex
+
+func addKeyMonitor(key []byte) {
+	monitorKeysMutex.Lock()
+	monitorKeys[string(key)] = struct{}{}
+	monitorKeysMutex.Unlock()
+}
+
+func removeKeyMonitor(key []byte) {
+	monitorKeysMutex.Lock()
+	delete(monitorKeys, string(key))
+	monitorKeysMutex.Unlock()
+}
+
+func filterSearchStatus(client *dht.SearchClient, function, format string, v ...interface{}) {
+	// check if the search client is actively being monitored
+	monitorKeysMutex.Lock()
+	_, ok := monitorKeys[string(client.Key)]
+	monitorKeysMutex.Unlock()
+	if !ok {
+		return
+	}
+
+	keyA := client.Key
+	if len(keyA) > 8 {
+		keyA = keyA[:8]
+	}
+
+	intend := " ->"
+	if function == "sendInfoRequest" {
+		intend = "    >"
+	}
+
+	fmt.Printf(intend+" ["+function+" "+hex.EncodeToString(keyA)+"] "+format, v...)
+}