1 files changed, 162 insertions, 0 deletions
diff --git a/cmd/gonf/ssh.go b/cmd/gonf/ssh.go
new file mode 100644
index 0000000..47bf2c5
--- /dev/null
+++ b/cmd/gonf/ssh.go
@@ -0,0 +1,162 @@
+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: %+v", err)
+	}
+	agentClient := agent.NewClient(sshc.agentConn)
+
+	hostKeyCallback, err := knownhosts.New(filepath.Join(getenv("HOME"), ".ssh/known_hosts"))
+	if err != nil {
+		return nil, fmt.Errorf("could not create hostkeycallback function: %+v", 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: %+v", 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,
+) (err error) {
+	session, err := sshc.client.NewSession()
+	if err != nil {
+		return fmt.Errorf("sshClient failed to create session: %+v", err)
+	}
+	defer func() {
+		if e := session.Close(); err == nil && e != io.EOF {
+			err = e
+		}
+	}()
+
+	file, err := os.Open(filename)
+	if err != nil {
+		return fmt.Errorf("sshClient failed to open file: %+v", err)
+	}
+	defer func() {
+		if e := file.Close(); err == nil {
+			err = e
+		}
+	}()
+
+	fi, err := file.Stat()
+	if err != nil {
+		return fmt.Errorf("sshClient failed to stat file: %+v", err)
+	}
+
+	w, err := session.StdinPipe()
+	if err != nil {
+		return fmt.Errorf("sshClient failed to open session stdin pipe: %+v", 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("sshClient failed to run scp: %+v", err)
+	}
+	go func() {
+		defer wg.Done()
+		if e := session.Wait(); e != nil {
+			errCh <- e
+		}
+	}()
+
+	go func() {
+		defer wg.Done()
+		defer func() {
+			if e := w.Close(); e != nil {
+				errCh <- e
+			}
+		}()
+		// 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
+		}
+	}()
+
+	var cancel context.CancelFunc
+	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
+}