feat(VCS): initial toying

cmd/vcs.go

@@ -0,0 +1,198 @@
+package cmd
+
+import (
+	"encoding/json"
+	"fmt"
+	"os"
+	"os/exec"
+	"path/filepath"
+	"strings"
+	"time"
+	"unicode/utf8"
+
+	"github.com/dgraph-io/badger/v4"
+	gap "github.com/muesli/go-app-paths"
+	"github.com/spf13/cobra"
+)
+
+var vcsCmd = &cobra.Command{
+	Use:   "vcs",
+	Short: "Version control utilities",
+}
+
+var vcsInitCmd = &cobra.Command{
+	Use:          "init",
+	Short:        "Initialise local version control for pda data",
+	SilenceUsage: true,
+	RunE: func(cmd *cobra.Command, args []string) error {
+		repoDir, err := vcsRepoRoot()
+		if err != nil {
+			return err
+		}
+		if err := os.MkdirAll(filepath.Join(repoDir), 0o750); err != nil {
+			return err
+		}
+
+		gitDir := filepath.Join(repoDir, ".git")
+		if _, err := os.Stat(gitDir); os.IsNotExist(err) {
+			if err := runGit(repoDir, "init"); err != nil {
+				return err
+			}
+		}
+
+		if err := writeGitignore(repoDir); err != nil {
+			return err
+		}
+
+		return nil
+	},
+}
+
+var vcsSnapshotCmd = &cobra.Command{
+	Use:          "snapshot",
+	Short:        "commit a snapshot into the vcs",
+	SilenceUsage: true,
+	RunE: func(cmd *cobra.Command, args []string) error {
+		repoDir, err := ensureVCSInitialized()
+		if err != nil {
+			return err
+		}
+
+		store := &Store{}
+		stores, err := store.AllStores()
+		if err != nil {
+			return err
+		}
+
+		for _, db := range stores {
+			if err := snapshotDB(store, repoDir, db); err != nil {
+				return fmt.Errorf("snapshot %q: %w", db, err)
+			}
+		}
+
+		if err := runGit(repoDir, "add", "snapshots"); err != nil {
+			return err
+		}
+
+		message := fmt.Sprintf("snapshot: %s", time.Now().UTC().Format(time.RFC3339))
+		if err := runGit(repoDir, "commit", "-m", message); err != nil {
+			fmt.Println(err.Error())
+			return nil
+		}
+
+		return nil
+	},
+}
+
+func init() {
+	vcsCmd.AddCommand(vcsInitCmd)
+	vcsCmd.AddCommand(vcsSnapshotCmd)
+	rootCmd.AddCommand(vcsCmd)
+}
+
+func vcsRepoRoot() (string, error) {
+	scope := gap.NewVendorScope(gap.User, "pda", "vcs")
+	dir, err := scope.DataPath("")
+	if err != nil {
+		return "", err
+	}
+	if err := os.MkdirAll(dir, 0o750); err != nil {
+		return "", err
+	}
+	return dir, nil
+}
+
+func ensureVCSInitialized() (string, error) {
+	repoDir, err := vcsRepoRoot()
+	if err != nil {
+		return "", err
+	}
+	if _, err := os.Stat(filepath.Join(repoDir, ".git")); err != nil {
+		if os.IsNotExist(err) {
+			return "", fmt.Errorf("vcs repository not initialised; run 'pda vcs init' first")
+		}
+		return "", err
+	}
+	return repoDir, nil
+}
+
+func writeGitignore(repoDir string) error {
+	path := filepath.Join(repoDir, ".gitignore")
+	content := strings.Join([]string{
+		"# generated by pda",
+		"*",
+		"!snapshots/",
+		"!snapshots/*.ndjson",
+		"",
+	}, "\n")
+	return os.WriteFile(path, []byte(content), 0o640)
+}
+
+func snapshotDB(store *Store, repoDir, db string) error {
+	snapDir := filepath.Join(repoDir, "snapshots")
+	if err := os.MkdirAll(snapDir, 0o750); err != nil {
+		return err
+	}
+	target := filepath.Join(snapDir, fmt.Sprintf("%s.ndjson", db))
+	f, err := os.Create(target)
+	if err != nil {
+		return err
+	}
+	defer f.Close()
+
+	trans := TransactionArgs{
+		key:      "@" + db,
+		readonly: true,
+		sync:     true,
+		transact: func(tx *badger.Txn, k []byte) error {
+			it := tx.NewIterator(badger.DefaultIteratorOptions)
+			defer it.Close()
+			for it.Rewind(); it.Valid(); it.Next() {
+				item := it.Item()
+				key := item.KeyCopy(nil)
+				meta := item.UserMeta()
+				isSecret := meta&metaSecret != 0
+				expiresAt := item.ExpiresAt()
+				if err := item.Value(func(v []byte) error {
+					entry := dumpEntry{
+						Key:    string(key),
+						Secret: isSecret,
+					}
+					if expiresAt > 0 {
+						ts := int64(expiresAt)
+						entry.ExpiresAt = &ts
+					}
+					if utf8.Valid(v) {
+						entry.Encoding = "text"
+						entry.Value = string(v)
+					} else {
+						encodeBase64(&entry, v)
+					}
+					payload, err := json.Marshal(entry)
+					if err != nil {
+						return err
+					}
+					_, err = fmt.Fprintln(f, string(payload))
+					return err
+				}); err != nil {
+					return err
+				}
+			}
+			return nil
+		},
+	}
+
+	if err := store.Transaction(trans); err != nil {
+		return err
+	}
+
+	return f.Sync()
+}
+
+func runGit(dir string, args ...string) error {
+	cmd := exec.Command("git", args...)
+	cmd.Dir = dir
+	cmd.Stdout = os.Stdout
+	cmd.Stderr = os.Stderr
+	return cmd.Run()
+}