gonf/cmd/gonf/ssh.go

149 lines
2.9 KiB
Go

package main
import (
"context"
"fmt"
"io"
"net"
"os"
"path/filepath"
"sync"
"time"
"golang.org/x/crypto/ssh"
"golang.org/x/crypto/ssh/agent"
"golang.org/x/crypto/ssh/knownhosts"
)
type sshClient struct {
agentConn net.Conn
client *ssh.Client
}
func newSSHClient(context context.Context,
getenv func(string) string,
destination string,
) (*sshClient, error) {
var sshc sshClient
var err error
socket := getenv("SSH_AUTH_SOCK")
if sshc.agentConn, err = net.Dial("unix", socket); err != nil {
return nil, fmt.Errorf("failed to open SSH_AUTH_SOCK: %w", err)
}
agentClient := agent.NewClient(sshc.agentConn)
hostKeyCallback, err := knownhosts.New(filepath.Join(getenv("HOME"), ".ssh/known_hosts"))
if err != nil {
return nil, fmt.Errorf("failed to create hostkeycallback function: %w", err)
}
config := &ssh.ClientConfig{
User: "root",
Auth: []ssh.AuthMethod{
ssh.PublicKeysCallback(agentClient.Signers),
},
HostKeyCallback: hostKeyCallback,
}
sshc.client, err = ssh.Dial("tcp", destination, config)
if err != nil {
return nil, fmt.Errorf("failed to dial: %w", err)
}
return &sshc, nil
}
func (sshc *sshClient) Close() error {
if err := sshc.client.Close(); err != nil {
return err
}
if err := sshc.agentConn.Close(); err != nil {
return err
}
return nil
}
func (sshc *sshClient) SendFile(
ctx context.Context,
stdout, stderr io.Writer,
filename string,
) error {
session, err := sshc.client.NewSession()
if err != nil {
return fmt.Errorf("failed to create ssh client session: %w", err)
}
defer session.Close()
file, err := os.Open(filename)
if err != nil {
return fmt.Errorf("failed to open file: %w", err)
}
defer file.Close()
fi, err := file.Stat()
if err != nil {
return fmt.Errorf("failed to stat file: %w", err)
}
w, err := session.StdinPipe()
if err != nil {
return fmt.Errorf("sshClient failed to open session stdin pipe: %w", err)
}
wg := sync.WaitGroup{}
wg.Add(2)
errCh := make(chan error, 2)
session.Stdout = stdout
session.Stderr = stderr
if err := session.Start("scp -t /usr/local/bin/gonf-run"); err != nil {
return fmt.Errorf("failed to run scp: %w", err)
}
go func() {
defer wg.Done()
if e := session.Wait(); e != nil {
errCh <- e
}
}()
go func() {
defer wg.Done()
defer w.Close()
// Write "C{mode} {size} {filename}\n"
if _, e := fmt.Fprintf(w, "C%#o %d %s\n", 0700, fi.Size(), "gonf-run"); e != nil {
errCh <- e
return
}
// Write the file's contents.
if _, e := io.Copy(w, file); e != nil {
errCh <- e
return
}
// End with a null byte.
if _, e := fmt.Fprint(w, "\x00"); e != nil {
errCh <- e
}
}()
ctx, cancel := context.WithTimeout(ctx, 60*time.Second)
defer cancel()
// wait for all waitgroup.Done() or the timeout
c := make(chan struct{})
go func() {
wg.Wait()
close(c)
}()
select {
case <-c:
case <-ctx.Done():
return ctx.Err()
}
close(errCh)
for err := range errCh {
if err != nil {
return err
}
}
return nil
}