Add flag to retrieve N most recent migrations

README.md

@@ -68,6 +68,7 @@ Options:
     	migrations table name (default "goose_db_version")
   -h	print help
   -v	enable verbose mode
+  -n	retrieve the N most recent migrations
   -version
     	print version
 

cmd/goose/main.go

@@ -18,6 +18,7 @@ var (
 	version    = flags.Bool("version", false, "print version")
 	certfile   = flags.String("certfile", "", "file path to root CA's certificates in pem format (only support on mysql)")
 	sequential = flags.Bool("s", false, "use sequential numbering for new migrations")
+	recent     = flags.Int("n", 0, "retrieve the N most recent migrations")
 )
 
 func main() {
@@ -34,6 +35,9 @@ func main() {
 	if *sequential {
 		goose.SetSequential(true)
 	}
+	if *recent > 0 {
+		goose.SetRecentLimit(*recent)
+	}
 	goose.SetTableName(*table)
 
 	args := flags.Args()

migrate.go

@@ -21,6 +21,9 @@ var (
 	MaxVersion int64 = 9223372036854775807 // max(int64)
 
 	registeredGoMigrations = map[int64]*Migration{}
+
+	// recent with value of 0 is no limit
+	recent = 0
 )
 
 // Migrations slice.
@@ -78,6 +81,20 @@ func (ms Migrations) Last() (*Migration, error) {
 	return ms[len(ms)-1], nil
 }
 
+// Last gets the last migration.
+func (ms Migrations) LastN(n int) (Migrations, error) {
+	if len(ms) == 0 {
+		return nil, ErrNoNextVersion
+	}
+
+	start := len(ms) - n - 1
+	if start < 0 {
+		start = 0
+	}
+
+	return ms[start : len(ms)-1], nil
+}
+
 // Versioned gets versioned migrations.
 func (ms Migrations) versioned() (Migrations, error) {
 	var migrations Migrations
@@ -199,6 +216,13 @@ func CollectMigrations(dirpath string, current, target int64) (Migrations, error
 		}
 	}
 
+	if recent > 0 {
+		migrations, err = migrations.LastN(recent)
+		if err != nil {
+			return nil, err
+		}
+	}
+
 	migrations = sortAndConnectMigrations(migrations)
 
 	return migrations, nil
@@ -317,3 +341,7 @@ func GetDBVersion(db *sql.DB) (int64, error) {
 
 	return version, nil
 }
+
+func SetRecentLimit(r int) {
+	recent = r
+}