feat: use persistent to reuse cert

examples/autotls/.gitignore

@@ -1,2 +1,3 @@
 autotls
 p2p-forge-certs/
+identity.key

examples/autotls/identity.go

@@ -0,0 +1,49 @@
+package main
+
+// Borrowed from https://github.com/libp2p/go-libp2p-relay-daemon/blob/master/identity.go
+
+import (
+	"os"
+
+	"github.com/libp2p/go-libp2p/core/crypto"
+)
+
+// LoadIdentity reads a private key from the given path and, if it does not
+// exist, generates a new one.
+func LoadIdentity(keyPath string) (crypto.PrivKey, error) {
+	if _, err := os.Stat(keyPath); err == nil {
+		return ReadIdentity(keyPath)
+	} else if os.IsNotExist(err) {
+		logger.Infof("Generating peer identity in %s\n", keyPath)
+		return GenerateIdentity(keyPath)
+	} else {
+		return nil, err
+	}
+}
+
+// ReadIdentity reads a private key from the given path.
+func ReadIdentity(path string) (crypto.PrivKey, error) {
+	bytes, err := os.ReadFile(path)
+	if err != nil {
+		return nil, err
+	}
+
+	return crypto.UnmarshalPrivateKey(bytes)
+}
+
+// GenerateIdentity writes a new random private key to the given path.
+func GenerateIdentity(path string) (crypto.PrivKey, error) {
+	privk, _, err := crypto.GenerateKeyPair(crypto.Ed25519, 0)
+	if err != nil {
+		return nil, err
+	}
+
+	bytes, err := crypto.MarshalPrivateKey(privk)
+	if err != nil {
+		return nil, err
+	}
+
+	err = os.WriteFile(path, bytes, 0400)
+
+	return privk, err
+}

examples/autotls/main.go

@@ -18,20 +18,21 @@ import (
 	ws "github.com/libp2p/go-libp2p/p2p/transport/websocket"
 )
 
-var logger = log.Logger("example")
+var logger = log.Logger("autotls-example")
 
 const userAgent = "go-libp2p/example/autotls"
+const identityKeyFile = "identity.key"
 
 func main() {
 	// Create a background context
 	ctx := context.Background()
 
 	log.SetLogLevel("*", "error")
-	log.SetLogLevel("example", "debug")   // Set the log level for the example to debug
-	log.SetLogLevel("basichost", "info")  // Set the log level for the basichost package to info
-	log.SetLogLevel("autotls", "debug")   // Set the log level for the autotls-example package to debug
-	log.SetLogLevel("p2p-forge", "debug") // Set the log level for the p2pforge package to debug
-	log.SetLogLevel("nat", "debug")       // Set the log level for the libp2p nat package to debug
+	log.SetLogLevel("autotls-example", "debug") // Set the log level for the example to debug
+	log.SetLogLevel("basichost", "info")        // Set the log level for the basichost package to info
+	log.SetLogLevel("autotls", "debug")         // Set the log level for the autotls-example package to debug
+	log.SetLogLevel("p2p-forge", "debug")       // Set the log level for the p2pforge package to debug
+	log.SetLogLevel("nat", "debug")             // Set the log level for the libp2p nat package to debug
 
 	certLoaded := make(chan bool, 1) // Create a channel to signal when the cert is loaded
 
@@ -74,9 +75,16 @@ func main() {
 	certManager.Start()
 	defer certManager.Stop()
 
+	// Load or generate a persistent peer identity key
+	privKey, err := LoadIdentity(identityKeyFile)
+	if err != nil {
+		panic(err)
+	}
+
 	opts := []libp2p.Option{
-		libp2p.DisableRelay(), // Disable relay, since we need a public IP address
-		libp2p.NATPortMap(),   // Attempt to open ports using UPnP for NATed hosts.
+		libp2p.Identity(privKey), // Use the loaded identity key
+		libp2p.DisableRelay(),    // Disable relay, since we need a public IP address
+		libp2p.NATPortMap(),      // Attempt to open ports using UPnP for NATed hosts.
 
 		libp2p.ListenAddrStrings(
 			// Configure default catch-all listeners for TCP and UDP