136 lines
3.3 KiB
Go
136 lines
3.3 KiB
Go
/*
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Copyright 2021 The Dapr Authors
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Licensed under the Apache License, Version 2.0 (the "License");
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you may not use this file except in compliance with the License.
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You may obtain a copy of the License at
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http://www.apache.org/licenses/LICENSE-2.0
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Unless required by applicable law or agreed to in writing, software
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distributed under the License is distributed on an "AS IS" BASIS,
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WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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See the License for the specific language governing permissions and
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limitations under the License.
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*/
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package kafka
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import (
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"context"
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"strings"
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"github.com/dapr/kit/logger"
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"github.com/dapr/components-contrib/bindings"
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"github.com/dapr/components-contrib/internal/component/kafka"
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)
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const (
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publishTopic = "publishTopic"
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topics = "topics"
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)
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type Binding struct {
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kafka *kafka.Kafka
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publishTopic string
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topics []string
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logger logger.Logger
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subscribeCtx context.Context
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subscribeCancel context.CancelFunc
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}
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// NewKafka returns a new kafka binding instance.
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func NewKafka(logger logger.Logger) bindings.InputOutputBinding {
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k := kafka.NewKafka(logger)
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// in kafka binding component, disable consumer retry by default
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k.DefaultConsumeRetryEnabled = false
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return &Binding{
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kafka: k,
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logger: logger,
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}
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}
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func (b *Binding) Init(metadata bindings.Metadata) error {
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b.subscribeCtx, b.subscribeCancel = context.WithCancel(context.Background())
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err := b.kafka.Init(metadata.Properties)
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if err != nil {
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return err
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}
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val, ok := metadata.Properties[publishTopic]
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if ok && val != "" {
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b.publishTopic = val
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}
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val, ok = metadata.Properties[topics]
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if ok && val != "" {
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b.topics = strings.Split(val, ",")
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}
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return nil
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}
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func (b *Binding) Operations() []bindings.OperationKind {
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return []bindings.OperationKind{bindings.CreateOperation}
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}
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func (b *Binding) Close() (err error) {
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b.subscribeCancel()
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return b.kafka.Close()
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}
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func (b *Binding) Invoke(_ context.Context, req *bindings.InvokeRequest) (*bindings.InvokeResponse, error) {
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err := b.kafka.Publish(b.publishTopic, req.Data, req.Metadata)
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return nil, err
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}
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func (b *Binding) Read(ctx context.Context, handler bindings.Handler) error {
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if len(b.topics) == 0 {
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b.logger.Warnf("kafka binding: no topic defined, input bindings will not be started")
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return nil
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}
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handlerConfig := kafka.SubscriptionHandlerConfig{
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IsBulkSubscribe: false,
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Handler: adaptHandler(handler),
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}
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for _, t := range b.topics {
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b.kafka.AddTopicHandler(t, handlerConfig)
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}
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go func() {
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// Wait for context cancelation
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select {
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case <-ctx.Done():
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case <-b.subscribeCtx.Done():
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}
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// Remove the topic handler before restarting the subscriber
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for _, t := range b.topics {
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b.kafka.RemoveTopicHandler(t)
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}
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// If the component's context has been canceled, do not re-subscribe
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if b.subscribeCtx.Err() != nil {
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return
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}
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err := b.kafka.Subscribe(b.subscribeCtx)
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if err != nil {
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b.logger.Errorf("kafka binding: error re-subscribing: %v", err)
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}
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}()
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return b.kafka.Subscribe(b.subscribeCtx)
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}
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func adaptHandler(handler bindings.Handler) kafka.EventHandler {
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return func(ctx context.Context, event *kafka.NewEvent) error {
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_, err := handler(ctx, &bindings.ReadResponse{
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Data: event.Data,
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Metadata: event.Metadata,
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ContentType: event.ContentType,
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})
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return err
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}
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}
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