Merge pull request #60 from smacker/reset_refresh

Reset & refresh commands

cmd/goose/main.go

@@ -116,6 +116,7 @@ Commands:
     down                 Roll back the version by 1
     down-to VERSION      Roll back to a specific VERSION
     redo                 Re-run the latest migration
+    reset                Roll back all migrations
     status               Dump the migration status for the current DB
     version              Print the current version of the database
     create NAME [sql|go] Creates new migration file with next version

goose.go

@@ -68,6 +68,10 @@ func Run(command string, db *sql.DB, dir string, args ...string) error {
 		if err := Redo(db, dir); err != nil {
 			return err
 		}
+	case "reset":
+		if err := Reset(db, dir); err != nil {
+			return err
+		}
 	case "status":
 		if err := Status(db, dir); err != nil {
 			return err

reset.go

@@ -0,0 +1,59 @@
+package goose
+
+import (
+	"database/sql"
+	"log"
+	"sort"
+)
+
+// Reset rolls back all migrations
+func Reset(db *sql.DB, dir string) error {
+	migrations, err := CollectMigrations(dir, minVersion, maxVersion)
+	if err != nil {
+		return err
+	}
+	statuses, err := dbMigrationsStatus(db)
+	if err != nil {
+		return err
+	}
+	sort.Sort(sort.Reverse(migrations))
+
+	for _, migration := range migrations {
+		if !statuses[migration.Version] {
+			continue
+		}
+		if err = migration.Down(db); err != nil {
+			return err
+		}
+	}
+
+	return nil
+}
+
+func dbMigrationsStatus(db *sql.DB) (map[int64]bool, error) {
+	rows, err := GetDialect().dbVersionQuery(db)
+	if err != nil {
+		return map[int64]bool{}, createVersionTable(db)
+	}
+	defer rows.Close()
+
+	// The most recent record for each migration specifies
+	// whether it has been applied or rolled back.
+
+	result := make(map[int64]bool)
+
+	for rows.Next() {
+		var row MigrationRecord
+		if err = rows.Scan(&row.VersionID, &row.IsApplied); err != nil {
+			log.Fatal("error scanning rows:", err)
+		}
+
+		if _, ok := result[row.VersionID]; ok {
+			continue
+		}
+
+		result[row.VersionID] = row.IsApplied
+	}
+
+	return result, nil
+}