Merge pull request #16 from knocknote/feature/add_show_query_executor

add show query executor

exec/exec.go

@@ -117,6 +117,8 @@ func NewQueryExecutor(ctx context.Context, conn *connection.DBConnection, tx *co
 		return NewDeleteQueryExecutor(base)
 	case sqlparser.Drop:
 		return NewDropQueryExecutor(base)
+	case sqlparser.Show:
+		return NewShowQueryExecutor(base)
 	default:
 	}
 	return nil

exec/show.go

@@ -0,0 +1,59 @@
+package exec
+
+import (
+	"database/sql"
+
+	"github.com/pkg/errors"
+	"go.knocknote.io/octillery/sqlparser"
+)
+
+// ShowQueryExecutor inherits QueryExecutorBase structure
+type ShowQueryExecutor struct {
+	*QueryExecutorBase
+}
+
+// NewShowQueryExecutor creates instance of ShowQueryExecutor
+func NewShowQueryExecutor(base *QueryExecutorBase) *ShowQueryExecutor {
+	return &ShowQueryExecutor{base}
+}
+
+// Query show multiple rows from any one of shards.
+func (e *ShowQueryExecutor) Query() ([]*sql.Rows, error) {
+	query, ok := e.query.(*sqlparser.QueryBase)
+	if !ok {
+		return nil, errors.New("cannot convert to sqlparser.Query to *sqlparser.QueryBase")
+	}
+
+	for _, shardConn := range e.conn.ShardConnections.AllShard() {
+		rows, err := e.execQuery(shardConn, query.Text, query.Args...)
+		if err != nil {
+			return nil, errors.WithStack(err)
+		}
+		return []*sql.Rows{rows}, nil
+	}
+
+	return nil, nil
+}
+
+// QueryRow show row from any one of shards.
+func (e *ShowQueryExecutor) QueryRow() (*sql.Row, error) {
+	query, ok := e.query.(*sqlparser.QueryBase)
+	if !ok {
+		return nil, errors.New("cannot convert to sqlparser.Query to *sqlparser.QueryBase")
+	}
+
+	for _, shardConn := range e.conn.ShardConnections.AllShard() {
+		row, err := e.execQueryRow(shardConn, query.Text, query.Args...)
+		if err != nil {
+			return nil, errors.WithStack(err)
+		}
+		return row, nil
+	}
+
+	return nil, nil
+}
+
+// Exec doesn't support in ShowQueryExecutor, returns always error.
+func (e *ShowQueryExecutor) Exec() (sql.Result, error) {
+	return nil, errors.New("ShowQueryExecutor cannot invoke Exec()")
+}