/
connection.go
118 lines (92 loc) · 2 KB
/
connection.go
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package connector
import (
"bytes"
"io/ioutil"
"strings"
"sync"
"time"
"golang.org/x/crypto/ssh"
)
const timeoutInSeconds = 5
var (
cachedConfig *ssh.ClientConfig
lock = &sync.Mutex{}
)
func config(user, keyFile string) (*ssh.ClientConfig, error) {
lock.Lock()
defer lock.Unlock()
if cachedConfig != nil {
return cachedConfig, nil
}
pk, err := loadPublicKeyFile(keyFile)
if err != nil {
return nil, err
}
cachedConfig = &ssh.ClientConfig{
User: user,
Auth: []ssh.AuthMethod{pk},
HostKeyCallback: ssh.InsecureIgnoreHostKey(),
Timeout: timeoutInSeconds * time.Second,
}
return cachedConfig, nil
}
// NewSSSHConnection connects to device
func NewSSSHConnection(host, user, keyFile string) (*SSHConnection, error) {
if !strings.Contains(host, ":") {
host = host + ":22"
}
c := &SSHConnection{Host: host}
err := c.Connect(user, keyFile)
if err != nil {
return nil, err
}
return c, nil
}
// SSHConnection encapsulates the connection to the device
type SSHConnection struct {
conn *ssh.Client
Host string
}
// Connect connects to the device
func (c *SSHConnection) Connect(user, keyFile string) error {
config, err := config(user, keyFile)
if err != nil {
return err
}
c.conn, err = ssh.Dial("tcp", c.Host, config)
return err
}
// RunCommand runs a command against the device
func (c *SSHConnection) RunCommand(cmd string) ([]byte, error) {
session, err := c.conn.NewSession()
if err != nil {
return nil, err
}
defer session.Close()
var b = &bytes.Buffer{}
session.Stdout = b
err = session.Run(cmd)
if err != nil {
return nil, err
}
return b.Bytes(), nil
}
// Close closes connection
func (c *SSHConnection) Close() {
if c.conn == nil {
return
}
c.conn.Close()
c.conn = nil
}
func loadPublicKeyFile(file string) (ssh.AuthMethod, error) {
b, err := ioutil.ReadFile(file)
if err != nil {
return nil, err
}
key, err := ssh.ParsePrivateKey(b)
if err != nil {
return nil, err
}
return ssh.PublicKeys(key), nil
}