helper for creating a sftpclient

sftp.go

package sftpclient

import (
	"fmt"
	"github.com/pkg/sftp"
	"golang.org/x/crypto/ssh"
	"net"
	"time"
)

// SFTPClient contains the actual client and ssh connection
type SFTPClient struct {
	Client     *sftp.Client
	connection *ssh.Client
}

type SSHServer struct {
	Address   string          // host:port
	Host      string          // IP address
	Port      int             // port
	IsSSH     bool            // true if server is running SSH on address:port
	Banner    string          // banner text, if any
	Cert      ssh.Certificate // server's certificate
	Hostname  string          // hostname
	PublicKey ssh.PublicKey   // server's public key
}

type HostAuthorityCallBack func(ssh.PublicKey, string) bool
type IsRevokedCallback func(cert *ssh.Certificate) bool

// New will construct sftp client to be consumed
func New(user, pass, host string, port int) (*SFTPClient, error) {
	s := &SSHServer{
		Host: host,
		Port: port,
	}

	certCheck := &ssh.CertChecker{
		IsHostAuthority: hostAuthCallback(),
		IsRevoked:       certCallback(s),
		HostKeyFallback: hostCallback(s),
	}

	cf := &ssh.ClientConfig{
		User: user,
		Auth: []ssh.AuthMethod{
			ssh.Password(pass),
		},
		Timeout: 30 * time.Second,
		Config: ssh.Config{
			Ciphers: []string{"aes128-ctr", "aes192-ctr", "aes256-ctr"},
		},
		HostKeyCallback: certCheck.CheckHostKey,
	}

	addr := fmt.Sprintf("%s:%d", host, port)

	conn, err := ssh.Dial("tcp", addr, cf)
	if err != nil {
		return nil, err
	}

	sftpClient, err := sftp.NewClient(conn)
	if err != nil {
		return nil, err
	}

	var sftpConsole SFTPClient
	sftpConsole.connection = conn
	sftpConsole.Client = sftpClient

	return &sftpConsole, nil
}

// Close will assist closing all connections
func (sf *SFTPClient) Close() {
	sf.connection.Close()
	sf.Client.Close()
}

func hostAuthCallback() HostAuthorityCallBack {
	return func(p ssh.PublicKey, addr string) bool {
		return true
	}
}

func certCallback(s *SSHServer) IsRevokedCallback {
	return func(cert *ssh.Certificate) bool {
		s.Cert = *cert
		s.IsSSH = true

		return false
	}
}

func hostCallback(s *SSHServer) ssh.HostKeyCallback {
	return func(hostname string, remote net.Addr, key ssh.PublicKey) error {
		s.Hostname = hostname
		s.PublicKey = key
		return nil
	}
}