Add create-next command to generate sequential numbering of migrations (

pressly#25)

README.md

@@ -42,12 +42,13 @@ Options:
     	directory with migration files (default ".")
 
 Commands:
-    up         Migrate the DB to the most recent version available
-    down       Roll back the version by 1
-    redo       Re-run the latest migration
-    status     Dump the migration status for the current DB
-    dbversion  Print the current version of the database
-    create     Creates a blank migration template
+    up          Migrate the DB to the most recent version available
+    down        Roll back the version by 1
+    redo        Re-run the latest migration
+    status      Dump the migration status for the current DB
+    dbversion   Print the current version of the database
+    create      Creates a blank migration template
+    create-next Creates a blank migration template with next sequential version
 ```
 ## create
 

create.go

@@ -7,8 +7,24 @@ import (
 )
 
 // Create writes a new blank migration file.
-func Create(db *sql.DB, dir, name, migrationType string) error {
-	path, err := CreateMigration(name, migrationType, dir, time.Now())
+func Create(db *sql.DB, dir, name, migrationType string, sequential bool) error {
+	var version string
+	if !sequential {
+		version = time.Now().Format("20060102150405")
+	} else {
+		m, err := LastMigration(dir)
+		var last int64
+		if err != nil {
+			if err != ErrNoNextVersion {
+				return err
+			}
+			last = 0;
+		} else {
+			last = m.Version
+		}
+		version = fmt.Sprintf("%d", last + 1)
+	}
+	path, err := CreateMigration(name, migrationType, dir, version)
 	if err != nil {
 		return err
 	}

goose.go

@@ -44,7 +44,19 @@ func Run(command string, db *sql.DB, dir string, args ...string) error {
 		if len(args) == 2 {
 			migrationType = args[1]
 		}
-		if err := Create(db, dir, args[0], migrationType); err != nil {
+		if err := Create(db, dir, args[0], migrationType, false); err != nil {
+			return err
+		}
+	case "create-next":
+		if len(args) == 0 {
+			return fmt.Errorf("create must be of form: goose [OPTIONS] DRIVER DBSTRING create-next NAME [go|sql]")
+		}
+
+		migrationType := "go"
+		if len(args) == 2 {
+			migrationType = args[1]
+		}
+		if err := Create(db, dir, args[0], migrationType, true); err != nil {
 			return err
 		}
 	case "down":

migrate.go

@@ -147,6 +147,20 @@ func LoadMigrationPlugins(dirpath string) error {
 	return nil
 }
 
+// lastVersion returns version of last migration present in dirpath
+func LastMigration(dirpath string) (*Migration, error) {
+	ms, err := CollectMigrations(dirpath, 0, MaxVersion)
+	if err != nil {
+		return nil, err
+	}
+	m, err := ms.Last()
+
+	if err != nil {
+		return nil, err
+	}
+	return m, nil
+}
+
 func sortAndConnectMigrations(migrations Migrations) Migrations {
 	sort.Sort(migrations)
 

migration.go

@@ -104,13 +104,12 @@ func NumericComponent(name string) (int64, error) {
 	return n, e
 }
 
-func CreateMigration(name, migrationType, dir string, t time.Time) (path string, err error) {
+func CreateMigration(name, migrationType, dir string, version string) (path string, err error) {
 
 	if migrationType != "go" && migrationType != "sql" {
 		return "", errors.New("migration type must be 'go' or 'sql'")
 	}
 
-	version := t.Format("20060102150405")
 	filename := fmt.Sprintf("%v_%v.%v", version, name, migrationType)
 
 	fpath := filepath.Join(dir, filename)