add example

ssh/doc.go

@@ -6,7 +6,7 @@
 Package ssh in sshpiper is compatible with golang.org/x/crypto/ssh.
 All func and datatype left unchanged. You can use it like golang.org/x/crypto/ssh.
 
-Also, sshpiper provide additional APIs that allows build a piped ssh connection.
+Also, sshpiper provide additional APIs that allows you to build a piped ssh connection.
 
 SSH is a transport security protocol, an authentication protocol and a
 family of application protocols. The most typical application level

ssh/sshpiper_test.go

@@ -0,0 +1,56 @@
+package ssh
+
+import (
+	"io/ioutil"
+	"net"
+)
+
+func ExampleNewSSHPiperConn() {
+
+	// upstream addr
+	const serverAddr = "127.0.0.1:22"
+
+	piper := &SSHPiperConfig{
+		// return conn dial to serverAddr
+		FindUpstream: func(conn ConnMetadata) (net.Conn, error) {
+			c, err := net.Dial("tcp", serverAddr)
+			if err != nil {
+				return nil, err
+			}
+
+			return c, nil
+		},
+	}
+
+	// add private key
+	privateBytes, err := ioutil.ReadFile("id_rsa")
+	if err != nil {
+		panic("Failed to load private key")
+	}
+
+	private, err := ParsePrivateKey(privateBytes)
+	if err != nil {
+		panic("Failed to parse private key")
+	}
+
+	piper.AddHostKey(private)
+
+	// serve at a address
+	listener, err := net.Listen("tcp", "0.0.0.0:2022")
+	if err != nil {
+		panic("failed to listen for connection")
+	}
+	nConn, err := listener.Accept()
+	if err != nil {
+		panic("failed to accept incoming connection")
+	}
+
+	// accept nConn and build a SSHPipe
+	p, err := NewSSHPiperConn(nConn, piper)
+	if err != nil {
+		panic("failed to establish piped connection")
+	}
+
+	// wait util either side shutdown
+	p.Wait()
+}