feat: Add DialOption for DialWithXXX method more universal and add us…

…age for using SOCKS5 proxy to dial.

README.md

@@ -80,6 +80,25 @@ if err != nil {
 defer client.Close()
 ```
 
++ Dial by SOCKS5 proxy
+
+```go
+client, err := DialWithPasswd(addr, user, passwd, WithDialFuncOption(func(network string, address string) (net.Conn, error) {
+    // get proxy address from env or config
+    proxyAddress := os.Getenv("socks5_proxy")
+    dial, err := proxy.SOCKS5(network, proxyAddress, nil, nil)
+    if err != nil {
+        t.Fatal(err)
+    }
+    c, err := dial.Dial(network, address)
+    return c, err
+}))
+if err != nil {
+    handleErr(err)
+}
+defer client.Close()
+```
+
 ## execute commmand
 
 + Don't care about output, calling Run

sshclient.go

@@ -20,6 +20,21 @@ import (
 type remoteScriptType byte
 type remoteShellType byte
 
+// DialOption represents an option for Dial connection.
+type DialOption func(opt *dialOptions)
+
+// dialOptions contains all the options set by WithXxxOpt func as flow.
+type dialOptions struct {
+	dialFunc func(network string, address string) (net.Conn, error)
+}
+
+// WithDialFuncOption append dialFunc field to dialOptions
+func WithDialFuncOption(dialFunc func(network string, address string) (net.Conn, error)) DialOption {
+	return func(opt *dialOptions) {
+		opt.dialFunc = dialFunc
+	}
+}
+
 const (
 	cmdLine remoteScriptType = iota
 	rawScript
@@ -36,7 +51,11 @@ type Client struct {
 }
 
 // DialWithPasswd starts a client connection to the given SSH server with passwd authmethod.
-func DialWithPasswd(addr, user, passwd string) (*Client, error) {
+func DialWithPasswd(addr, user, passwd string, options ...DialOption) (*Client, error) {
+	opts := &dialOptions{}
+	for _, option := range options {
+		option(opts)
+	}
 	config := &ssh.ClientConfig{
 		User: user,
 		Auth: []ssh.AuthMethod{
@@ -45,11 +64,15 @@ func DialWithPasswd(addr, user, passwd string) (*Client, error) {
 		HostKeyCallback: ssh.HostKeyCallback(func(hostname string, remote net.Addr, key ssh.PublicKey) error { return nil }),
 	}
 
-	return Dial("tcp", addr, config)
+	return Dial("tcp", addr, config, opts)
 }
 
 // DialWithKey starts a client connection to the given SSH server with key authmethod.
-func DialWithKey(addr, user, keyfile string) (*Client, error) {
+func DialWithKey(addr, user, keyfile string, options ...DialOption) (*Client, error) {
+	opts := &dialOptions{}
+	for _, option := range options {
+		option(opts)
+	}
 	key, err := ioutil.ReadFile(keyfile)
 	if err != nil {
 		return nil, err
@@ -67,12 +90,15 @@ func DialWithKey(addr, user, keyfile string) (*Client, error) {
 		},
 		HostKeyCallback: ssh.HostKeyCallback(func(hostname string, remote net.Addr, key ssh.PublicKey) error { return nil }),
 	}
-
-	return Dial("tcp", addr, config)
+	return Dial("tcp", addr, config, opts)
 }
 
 // DialWithKeyWithPassphrase same as DialWithKey but with a passphrase to decrypt the private key
-func DialWithKeyWithPassphrase(addr, user, keyfile string, passphrase string) (*Client, error) {
+func DialWithKeyWithPassphrase(addr, user, keyfile string, passphrase string, options ...DialOption) (*Client, error) {
+	opts := &dialOptions{}
+	for _, option := range options {
+		option(opts)
+	}
 	key, err := ioutil.ReadFile(keyfile)
 	if err != nil {
 		return nil, err
@@ -91,12 +117,19 @@ func DialWithKeyWithPassphrase(addr, user, keyfile string, passphrase string) (*
 		HostKeyCallback: ssh.HostKeyCallback(func(hostname string, remote net.Addr, key ssh.PublicKey) error { return nil }),
 	}
 
-	return Dial("tcp", addr, config)
+	return Dial("tcp", addr, config, opts)
 }
 
 // Dial starts a client connection to the given SSH server.
 // This wraps ssh.Dial.
-func Dial(network, addr string, config *ssh.ClientConfig) (*Client, error) {
+func Dial(network, addr string, config *ssh.ClientConfig, opts *dialOptions) (*Client, error) {
+	if opts != nil && opts.dialFunc != nil {
+		conn, err := opts.dialFunc(network, addr)
+		if err != nil {
+			return nil, err
+		}
+		return DialWithConnection(conn, network, config)
+	}
 	sshClient, err := ssh.Dial(network, addr, config)
 	if err != nil {
 		return nil, err
@@ -114,9 +147,7 @@ func DialWithConnection(conn net.Conn, addr string, config *ssh.ClientConfig) (*
 
 	client := ssh.NewClient(ncc, chans, reqs)
 
-	return &Client{
-		client: client,
-	}, nil
+	return &Client{sshClient: client}, nil
 }
 
 // Close closes the underlying client network connection.