Add helper implementation

pkg/gitsshsigning/helper.go

@@ -0,0 +1,107 @@
+package gitsshsigning
+
+import (
+	"os"
+	"os/exec"
+	"path/filepath"
+	"strings"
+
+	"github.com/loft-sh/devpod/pkg/command"
+	"github.com/loft-sh/devpod/pkg/file"
+	"github.com/loft-sh/log/scanner"
+	"github.com/pkg/errors"
+)
+
+const (
+	HelperScript string = `#!/bin/bash
+
+devpod agent git-ssh-signature "$@"
+`
+	HelperScriptPath string = "/usr/local/bin/devpod-ssh-signature"
+	GitConfig        string = `
+[gpg "ssh"]
+	program = devpod-ssh-signature
+[gpg]
+	format = ssh
+`
+)
+
+func ConfigureHelper(binaryPath, userName, gitSigningKey string) error {
+	helperScriptFile, err := os.Create(HelperScriptPath)
+	if err != nil {
+		return err
+	}
+	_, err = helperScriptFile.WriteString(HelperScript)
+	if err != nil {
+		return err
+	}
+
+	err = helperScriptFile.Close()
+	if err != nil {
+		return err
+	}
+
+	err = exec.Command("chmod", "+x", HelperScriptPath).Run()
+	if err != nil {
+		return err
+	}
+
+	homeDir, err := command.GetHome(userName)
+	if err != nil {
+		return err
+	}
+
+	gitConfigPath := filepath.Join(homeDir, ".gitconfig")
+	out, err := os.ReadFile(gitConfigPath)
+	if err != nil && !os.IsNotExist(err) {
+		return err
+	}
+	config := string(out)
+	if !strings.Contains(config, "program = devpod-ssh-signature") {
+		content := removeSignatureHelper(config) + GitConfig
+
+		err = os.WriteFile(gitConfigPath, []byte(content), 0600)
+		if err != nil {
+			return errors.Wrap(err, "write git config")
+		}
+
+		err = file.Chown(userName, gitConfigPath)
+		if err != nil {
+			return err
+		}
+	}
+
+	return nil
+}
+
+func RemoveHelper() error {
+	// TODO
+	return nil
+}
+
+func removeSignatureHelper(content string) string {
+	scan := scanner.NewScanner(strings.NewReader(content))
+
+	isGpgSetup := false
+	out := []string{}
+	for scan.Scan() {
+		line := scan.Text()
+		if strings.TrimSpace(line) == "[gpg \"ssh\"]" {
+			isGpgSetup = true
+			continue
+		} else if strings.TrimSpace(line) == "[gpg]" {
+			isGpgSetup = true
+		} else if isGpgSetup {
+			trimmed := strings.TrimSpace(line)
+			if len(trimmed) > 0 && trimmed[0] == '[' {
+				isGpgSetup = false
+			} else {
+				continue
+			}
+		}
+
+		out = append(out, line)
+	}
+
+	return strings.Join(out, "\n")
+}