ekuiper-new/internal/topo/memory/sink.go

// Copyright 2021-2022 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 memory

import (
	"encoding/json"
	"fmt"
	"github.com/lf-edge/ekuiper/pkg/api"
	"strings"
)

type sink struct {
	topic        string
	hasTransform bool
}

func (s *sink) Open(ctx api.StreamContext) error {
	ctx.GetLogger().Debugf("Opening memory sink: %v", s.topic)
	CreatePub(s.topic)
	return nil
}

func (s *sink) Configure(props map[string]interface{}) error {
	if t, ok := props[IdProperty]; ok {
		if id, casted := t.(string); casted {
			if strings.ContainsAny(id, "#+") {
				return fmt.Errorf("invalid memory topic %s: wildcard found", id)
			}
			s.topic = id
		} else {
			return fmt.Errorf("can't cast value %s to string", t)
		}
	}
	if _, ok := props["dataTemplate"]; ok {
		s.hasTransform = true
	}
	return nil
}

func (s *sink) Collect(ctx api.StreamContext, data interface{}) error {
	ctx.GetLogger().Debugf("receive %+v", data)
	topic, err := ctx.ParseTemplate(s.topic, data)
	if err != nil {
		return err
	}
	if s.hasTransform {
		jsonBytes, _, err := ctx.TransformOutput(data)
		if err != nil {
			return err
		}
		m := make(map[string]interface{})
		err = json.Unmarshal(jsonBytes, &m)
		if err != nil {
			return fmt.Errorf("fail to decode data %s after applying dataTemplate for error %v", string(jsonBytes), err)
		}
		data = m
	}

	switch d := data.(type) {
	case []map[string]interface{}:
		for _, el := range d {
			Produce(ctx, topic, el)
		}
	case map[string]interface{}:
		Produce(ctx, topic, d)
	default:
		return fmt.Errorf("unrecognized format of %s", data)
	}
	return nil
}

func (s *sink) Close(ctx api.StreamContext) error {
	ctx.GetLogger().Debugf("closing memory sink")
	RemovePub(s.topic)
	return nil
}