vendor dependencies with dep

vendor/github.com/go-pg/migrations/migrations.go

@@ -0,0 +1,264 @@
+package migrations
+
+import (
+	"errors"
+	"fmt"
+	"io/ioutil"
+	"os"
+	"path"
+	"path/filepath"
+	"regexp"
+	"runtime"
+	"sort"
+	"strconv"
+	"strings"
+)
+
+var allMigrations []Migration
+
+type Migration struct {
+	Version int64
+	Up      func(DB) error
+	Down    func(DB) error
+}
+
+func (m *Migration) String() string {
+	return strconv.FormatInt(m.Version, 10)
+}
+
+// Register registers new database migration. Must be called
+// from file with name like "1_initialize_db.go", where:
+// - 1 - migration version;
+// - initialize_db - comment.
+func Register(up, down func(DB) error) error {
+	_, file, _, _ := runtime.Caller(1)
+	version, err := extractVersion(file)
+	if err != nil {
+		return err
+	}
+
+	allMigrations = append(allMigrations, Migration{
+		Version: version,
+		Up:      up,
+		Down:    down,
+	})
+	return nil
+}
+
+// Run runs command on the db. Supported commands are:
+// - init - creates gopg_migrations table.
+// - up - runs all available migrations.
+// - down - reverts last migration.
+// - reset - reverts all migrations.
+// - version - prints current db version.
+// - set_version - sets db version without running migrations.
+func Run(db DB, a ...string) (oldVersion, newVersion int64, err error) {
+	// Make a copy so there are no side effects of sorting.
+	migrations := make([]Migration, len(allMigrations))
+	copy(migrations, allMigrations)
+	return RunMigrations(db, migrations, a...)
+}
+
+// RunMigrations is like Run, but accepts list of migrations.
+func RunMigrations(db DB, migrations []Migration, a ...string) (oldVersion, newVersion int64, err error) {
+	sortMigrations(migrations)
+
+	var cmd string
+	if len(a) > 0 {
+		cmd = a[0]
+	}
+
+	if cmd == "init" {
+		err = createTables(db)
+		if err != nil {
+			return
+		}
+		cmd = "version"
+	}
+
+	oldVersion, err = Version(db)
+	if err != nil {
+		return
+	}
+
+	switch cmd {
+	case "create":
+		if len(a) < 2 {
+			fmt.Println("Please enter migration description")
+			return
+		}
+
+		var version int64
+		if len(migrations) > 0 {
+			version = migrations[len(migrations)-1].Version
+		}
+
+		filename := fmtMigrationFilename(version+1, strings.Join(a[1:], "_"))
+		err = createMigrationFile(filename)
+		if err != nil {
+			return
+		}
+
+		fmt.Println("created migration", filename)
+		return
+	case "version":
+		return
+	case "up", "":
+		for i := range migrations {
+			m := &migrations[i]
+			if m.Version <= oldVersion {
+				continue
+			}
+			err = m.Up(db)
+			if err != nil {
+				return
+			}
+			newVersion = m.Version
+			err = SetVersion(db, newVersion)
+			if err != nil {
+				return
+			}
+		}
+		return
+	case "down":
+		newVersion, err = down(db, migrations, oldVersion)
+		return
+	case "reset":
+		version := oldVersion
+		for {
+			newVersion, err = down(db, migrations, version)
+			if err != nil || newVersion == version {
+				return
+			}
+			version = newVersion
+		}
+	case "set_version":
+		if len(a) < 2 {
+			err = fmt.Errorf("set_version requires version as 2nd arg, e.g. set_version 42")
+			return
+		}
+
+		newVersion, err = strconv.ParseInt(a[1], 10, 64)
+		if err != nil {
+			return
+		}
+		err = SetVersion(db, newVersion)
+		return
+	default:
+		err = fmt.Errorf("unsupported command: %q", cmd)
+		return
+	}
+}
+
+func down(db DB, migrations []Migration, oldVersion int64) (newVersion int64, err error) {
+	if oldVersion == 0 {
+		return
+	}
+
+	var m *Migration
+	for i := len(migrations) - 1; i >= 0; i-- {
+		mm := &migrations[i]
+		if mm.Version <= oldVersion {
+			m = mm
+			break
+		}
+	}
+	if m == nil {
+		err = fmt.Errorf("migration %d not found\n", oldVersion)
+		return
+	}
+
+	if m.Down != nil {
+		err = m.Down(db)
+		if err != nil {
+			return
+		}
+	}
+
+	newVersion = m.Version - 1
+	err = SetVersion(db, newVersion)
+	return
+}
+
+func extractVersion(name string) (int64, error) {
+	base := filepath.Base(name)
+
+	if ext := filepath.Ext(base); ext != ".go" {
+		return 0, fmt.Errorf("can not extract version from %q", base)
+	}
+
+	idx := strings.IndexByte(base, '_')
+	if idx == -1 {
+		return 0, fmt.Errorf("can not extract version from %q", base)
+	}
+
+	n, err := strconv.ParseInt(base[:idx], 10, 64)
+	if err != nil {
+		return 0, err
+	}
+
+	if n <= 0 {
+		return 0, errors.New("version must be greater than zero")
+	}
+
+	return n, nil
+}
+
+type migrationSorter []Migration
+
+func (ms migrationSorter) Len() int {
+	return len(ms)
+}
+
+func (ms migrationSorter) Swap(i, j int) {
+	ms[i], ms[j] = ms[j], ms[i]
+}
+
+func (ms migrationSorter) Less(i, j int) bool {
+	return ms[i].Version < ms[j].Version
+}
+
+func sortMigrations(migrations []Migration) {
+	ms := migrationSorter(migrations)
+	sort.Sort(ms)
+}
+
+var migrationNameRE = regexp.MustCompile(`[^a-z0-9]+`)
+
+func fmtMigrationFilename(version int64, descr string) string {
+	descr = strings.ToLower(descr)
+	descr = migrationNameRE.ReplaceAllString(descr, "_")
+	return fmt.Sprintf("%d_%s.go", version, descr)
+}
+
+func createMigrationFile(filename string) error {
+	basepath, err := os.Getwd()
+	if err != nil {
+		return err
+	}
+	filename = path.Join(basepath, filename)
+
+	_, err = os.Stat(filename)
+	if !os.IsNotExist(err) {
+		return fmt.Errorf("file=%q already exists (%s)", filename, err)
+	}
+
+	return ioutil.WriteFile(filename, migrationTemplate, 0644)
+}
+
+var migrationTemplate = []byte(`package main
+
+import (
+	"github.com/go-pg/migrations"
+)
+
+func init() {
+	migrations.Register(func(db migrations.DB) error {
+		_, err := db.Exec("")
+		return err
+	}, func(db migrations.DB) error {
+		_, err := db.Exec("")
+		return err
+	})
+}
+`)