ekuiper-new/internal/topo/context/transform.go

// Copyright 2021 EMQ Technologies Co., Ltd.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

package context

import (
	"fmt"
	"github.com/lf-edge/ekuiper/internal/topo/transform"
)

const TransKey = "$$trans"

type TransConfig struct {
	Data  interface{}
	TFunc transform.TransFunc
}

// TransformOutput Lazy transform output to bytes
func (c *DefaultContext) TransformOutput() ([]byte, bool, error) {
	cc, ok := c.Value(TransKey).(*TransConfig)
	if ok {
		return cc.TFunc(cc.Data)
	}
	return nil, false, fmt.Errorf("no transform configured")
}