feat: wrap ssh with coder key (#894)

cli/gitssh.go

@@ -0,0 +1,62 @@
+package cli
+
+import (
+	"os"
+	"os/exec"
+
+	"github.com/spf13/cobra"
+	"golang.org/x/xerrors"
+)
+
+func gitssh() *cobra.Command {
+	return &cobra.Command{
+		Use:    "gitssh",
+		Hidden: true,
+		Short:  `Wraps the "ssh" command and uses the coder gitssh key for authentication`,
+		RunE: func(cmd *cobra.Command, args []string) error {
+			client, err := createClient(cmd)
+			if err != nil {
+				return xerrors.Errorf("create codersdk client: %w", err)
+			}
+			cfg := createConfig(cmd)
+			session, err := cfg.AgentSession().Read()
+			if err != nil {
+				return xerrors.Errorf("read agent session from config: %w", err)
+			}
+			client.SessionToken = session
+
+			key, err := client.AgentGitSSHKey(cmd.Context())
+			if err != nil {
+				return xerrors.Errorf("get agent git ssh token: %w", err)
+			}
+
+			privateKeyFile, err := os.CreateTemp("", "coder-gitsshkey-*")
+			if err != nil {
+				return xerrors.Errorf("create temp gitsshkey file: %w", err)
+			}
+			defer func() {
+				_ = privateKeyFile.Close()
+				_ = os.Remove(privateKeyFile.Name())
+			}()
+			_, err = privateKeyFile.WriteString(key.PrivateKey)
+			if err != nil {
+				return xerrors.Errorf("write to temp gitsshkey file: %w", err)
+			}
+			err = privateKeyFile.Close()
+			if err != nil {
+				return xerrors.Errorf("close temp gitsshkey file: %w", err)
+			}
+
+			a := append([]string{"-i", privateKeyFile.Name()}, args...)
+			c := exec.CommandContext(cmd.Context(), "ssh", a...)
+			c.Stdout = cmd.OutOrStdout()
+			c.Stdin = cmd.InOrStdin()
+			err = c.Run()
+			if err != nil {
+				return xerrors.Errorf("run ssh command: %w", err)
+			}
+
+			return nil
+		},
+	}
+}