Merge pull request #76 from agquick/master

Support for multiple statements in Cassandra cql migration files

database/cassandra/README.md

@@ -3,6 +3,9 @@
 * Drop command will not work on Cassandra 2.X because it rely on
 system_schema table which comes with 3.X
 * Other commands should work properly but are **not tested**
+* The Cassandra driver (gocql) does not natively support executing multipe statements in a single query. To allow for multiple statements in a single migration, you can use the `x-multi-statement` param. There are two important caveats:
+  * This mode splits the migration text into separately-executed statements by a semi-colon `;`. Thus `x-multi-statement` cannot be used when a statement in the migration contains a string with a semi-colon.
+  * The queries are not executed in any sort of transaction/batch, meaning you are responsible for fixing partial migrations.
 
 
 ## Usage
@@ -12,6 +15,7 @@ system_schema table which comes with 3.X
 | URL Query  | Default value | Description |
 |------------|-------------|-----------|
 | `x-migrations-table` | schema_migrations | Name of the migrations table |
+| `x-multi-statement` | false | Enable multiple statements to be ran in a single migration (See note above) |
 | `port` | 9042 | The port to bind to  |
 | `consistency` | ALL | Migration consistency
 | `protocol` |  | Cassandra protocol version (3 or 4)

database/cassandra/cassandra.go

@@ -31,6 +31,7 @@ var (
 type Config struct {
 	MigrationsTable string
 	KeyspaceName    string
+	MultiStatementEnabled bool
 }
 
 type Cassandra struct {
@@ -127,6 +128,7 @@ func (c *Cassandra) Open(url string) (database.Driver, error) {
 	return WithInstance(session, &Config{
 		KeyspaceName:    strings.TrimPrefix(u.Path, "/"),
 		MigrationsTable: u.Query().Get("x-migrations-table"),
+		MultiStatementEnabled: u.Query().Get("x-multi-statement") == "true",
 	})
 }
 
@@ -155,11 +157,26 @@ func (c *Cassandra) Run(migration io.Reader) error {
 	}
 	// run migration
 	query := string(migr[:])
+
+	if c.config.MultiStatementEnabled {
+		// split query by semi-colon
+		queries := strings.Split(query, ";")
+
+		for _, q := range(queries) {
+			tq := strings.TrimSpace(q)
+			if (tq == "") { continue }
+			if err := c.session.Query(tq).Exec(); err != nil {
+				// TODO: cast to Cassandra error and get line number
+				return database.Error{OrigErr: err, Err: "migration failed", Query: migr}
+			}
+		}
+		return nil
+	}
+
 	if err := c.session.Query(query).Exec(); err != nil {
 		// TODO: cast to Cassandra error and get line number
 		return database.Error{OrigErr: err, Err: "migration failed", Query: migr}
 	}
-
 	return nil
 }