Just a small script to connect to a host via SSH in Go :)

ssh.go

package main

import (
	"fmt"
	"log"
	"os"

	"golang.org/x/crypto/ssh"

	"github.com/kelseyhightower/envconfig"
)

type ConnectionOpts struct {
	PrivateKeyPath string `envconfig:"PRIVATE_KEY_PATH" default:""`
	RemoteHost     string `envconfig:"REMOTE_HOST" required:"true"`
	RemoteUser     string `envconfig:"REMOTE_USER" required:"true"`
	RemoteUserPass string `envconfig:"REMOTE_USER_PASS"`
}

func CreatePrivKeyAuth(privKeyPath string, user string) (ssh.ClientConfig, error) {

	// A public key may be used to authenticate against the remote
	// server by using an unencrypted PEM-encoded private key file.
	//
	// If you have an encrypted private key, the crypto/x509 package
	// can be used to decrypt it.

	key, err := os.ReadFile(privKeyPath)
	if err != nil {
		log.Fatalf("unable to read private key: %v", err)
	}

	// Create the Signer for this private key.
	signer, err := ssh.ParsePrivateKey(key)
	if err != nil {
		log.Fatalf("unable to parse private key: %v", err)
	}

	config := &ssh.ClientConfig{
		User: user,
		Auth: []ssh.AuthMethod{
			ssh.PublicKeys(signer),
		},
		HostKeyCallback: ssh.InsecureIgnoreHostKey(),
	}

	return *config, nil
}

func main() {

	var conOpts ConnectionOpts
	err := envconfig.Process("", &conOpts)
	if err != nil {
		log.Fatalf(err.Error())
	}

	var config ssh.ClientConfig
	if conOpts.PrivateKeyPath != "" {
		config, err = CreatePrivKeyAuth(conOpts.PrivateKeyPath, conOpts.RemoteUser)
	} else {

		config = ssh.ClientConfig{
			User: conOpts.RemoteUser,
			Auth: []ssh.AuthMethod{
				ssh.Password(conOpts.RemoteUserPass),
			},
			HostKeyCallback: ssh.InsecureIgnoreHostKey(),
		}
	}

	var remoteHost = fmt.Sprintf("%s:%s", conOpts.RemoteHost, "22")

	// Connect to the remote server and perform the SSH handshake.
	client, err := ssh.Dial("tcp", remoteHost, &config)
	if err != nil {
		log.Fatalf("unable to connect: %v", err)
	}
	defer client.Close()

}