init - add project files

cmd/metagen/migrations.go

@@ -0,0 +1,242 @@
+package main
+
+import (
+	"errors"
+	"fmt"
+	"log"
+	"os"
+	"path/filepath"
+	"strconv"
+	"strings"
+	"time"
+
+	"github.com/golang-migrate/migrate/v4"
+	_ "github.com/golang-migrate/migrate/v4/database/sqlite3"
+	_ "github.com/golang-migrate/migrate/v4/source/file"
+)
+
+// create
+func maybeCreateSqliteDb() {
+	if _, err := os.Stat("./passwords.db"); err != nil {
+		fmt.Printf("Creating new sqlite database")
+		err := os.WriteFile("./passwords.db", nil, 0755)
+		if err != nil {
+			fmt.Printf("Error creating Sqlite database.")
+			os.Exit(1)
+		}
+
+		m, err := migrate.New(
+			"file://./migrations",
+			"sqlite3://passwords.db",
+		)
+
+		if err != nil {
+			printStatus(false)
+			fmt.Println(err.Error())
+			os.Exit(1)
+		}
+
+		mErr := m.Up()
+		if mErr != nil {
+			printStatus(false)
+			fmt.Println(mErr.Error())
+			os.Exit(1)
+		}
+
+		printStatus(true)
+	}
+}
+
+// handle the running and creation of migrations
+func migrations(args []string) {
+	if len(args) < 2 {
+		fmt.Println("Usage: metagen migrate [up, down, goto {V}, create {migration name}]")
+		os.Exit(1)
+	}
+
+	maybeCreateSqliteDb()
+
+	m, err := migrate.New(
+		"file://./migrations",
+		"sqlite3://passwords.db",
+	)
+
+	if err != nil {
+		fmt.Println(err.Error())
+		os.Exit(1)
+	}
+
+	migrateNum := 0
+
+	if len(args) >= 3 && args[1] != "create" {
+		var parseErr error
+		migrateNum, parseErr = strconv.Atoi(args[2])
+		if parseErr != nil {
+			fmt.Println("Please provide a valid migration number.")
+			os.Exit(1)
+		}
+	}
+
+	m.PrefetchMigrations = migrate.DefaultPrefetchMigrations
+
+	switch args[1] {
+	case "up":
+		err := m.Up()
+		if err != nil {
+			fmt.Println(err.Error())
+		}
+	case "down":
+		err := m.Down()
+		if err != nil {
+			fmt.Println(err.Error())
+		}
+	case "goto":
+		err := m.Migrate(uint(migrateNum))
+		if err != nil {
+			fmt.Println(err.Error())
+		}
+	case "create":
+		if len(args) < 3 {
+			fmt.Println("Please provide a name for the new migration.")
+			os.Exit(1)
+		}
+		createCmd("./migrations", time.Now(), defaultTimeFormat, args[2], "sql", true, 7, true)
+	}
+}
+
+const (
+	defaultTimeFormat = "20060102150405"
+	defaultTimezone   = "UTC"
+)
+
+var (
+	errInvalidSequenceWidth     = errors.New("Digits must be positive")
+	errIncompatibleSeqAndFormat = errors.New("The seq and format options are mutually exclusive")
+	errInvalidTimeFormat        = errors.New("Time format may not be empty")
+)
+
+func createFile(filename string) error {
+	// create exclusive (fails if file already exists)
+	// os.Create() specifies 0666 as the FileMode, so we're doing the same
+	f, err := os.OpenFile(filename, os.O_RDWR|os.O_CREATE|os.O_EXCL, 0666)
+
+	if err != nil {
+		return err
+	}
+
+	return f.Close()
+}
+
+func nextSeqVersion(matches []string, seqDigits int) (string, error) {
+	if seqDigits <= 0 {
+		return "", errInvalidSequenceWidth
+	}
+
+	nextSeq := uint64(1)
+
+	if len(matches) > 0 {
+		filename := matches[len(matches)-1]
+		matchSeqStr := filepath.Base(filename)
+		idx := strings.Index(matchSeqStr, "_")
+
+		if idx < 1 { // Using 1 instead of 0 since there should be at least 1 digit
+			return "", fmt.Errorf("Malformed migration filename: %s", filename)
+		}
+
+		var err error
+		matchSeqStr = matchSeqStr[0:idx]
+		nextSeq, err = strconv.ParseUint(matchSeqStr, 10, 64)
+
+		if err != nil {
+			return "", err
+		}
+
+		nextSeq++
+	}
+
+	version := fmt.Sprintf("%0[2]*[1]d", nextSeq, seqDigits)
+
+	if len(version) > seqDigits {
+		return "", fmt.Errorf("Next sequence number %s too large. At most %d digits are allowed", version, seqDigits)
+	}
+
+	return version, nil
+}
+
+func timeVersion(startTime time.Time, format string) (version string, err error) {
+	switch format {
+	case "":
+		err = errInvalidTimeFormat
+	case "unix":
+		version = strconv.FormatInt(startTime.Unix(), 10)
+	case "unixNano":
+		version = strconv.FormatInt(startTime.UnixNano(), 10)
+	default:
+		version = startTime.Format(format)
+	}
+
+	return
+}
+
+func createCmd(dir string, startTime time.Time, format string, name string, ext string, seq bool, seqDigits int, print bool) error {
+	if seq && format != defaultTimeFormat {
+		return errIncompatibleSeqAndFormat
+	}
+
+	var version string
+	var err error
+
+	dir = filepath.Clean(dir)
+	ext = "." + strings.TrimPrefix(ext, ".")
+
+	if seq {
+		matches, err := filepath.Glob(filepath.Join(dir, "*"+ext))
+
+		if err != nil {
+			return err
+		}
+
+		version, err = nextSeqVersion(matches, seqDigits)
+
+		if err != nil {
+			return err
+		}
+	} else {
+		version, err = timeVersion(startTime, format)
+
+		if err != nil {
+			return err
+		}
+	}
+
+	versionGlob := filepath.Join(dir, version+"_*"+ext)
+	matches, err := filepath.Glob(versionGlob)
+
+	if err != nil {
+		return err
+	}
+
+	if len(matches) > 0 {
+		return fmt.Errorf("duplicate migration version: %s", version)
+	}
+
+	if err = os.MkdirAll(dir, os.ModePerm); err != nil {
+		return err
+	}
+
+	for _, direction := range []string{"up", "down"} {
+		basename := fmt.Sprintf("%s_%s.%s%s", version, name, direction, ext)
+		filename := filepath.Join(dir, basename)
+
+		if err = createFile(filename); err != nil {
+			return err
+		}
+
+		if print {
+			absPath, _ := filepath.Abs(filename)
+			log.Println(absPath)
+		}
+	}
+
+	return nil
+}