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Watermill

Handler

将 4 个阶段的逻辑处理定义为 Handler

测试发现，添加的 handler 会被覆盖掉，故考虑添加为 middleware 且 4 个阶段的处理逻辑针对不同 topic 是相同的。

参考https://watermill.io/docs/messages-router/实现不同topic（不同事件）走不同的Handler处理逻辑，相同处理逻辑则可以使用MiddleWare(https://watermill.io/docs/middlewares/)

Middleware

ProfileCtx实现 context.Context 接口

// Package consumer
// @Author xzx 2023/8/11 18:53:00
package consumer

import (
	"context"
	"github.com/Shopify/sarama"
	"github.com/ThreeDotsLabs/watermill"
	"github.com/ThreeDotsLabs/watermill-kafka/v2/pkg/kafka"
	"github.com/ThreeDotsLabs/watermill/message"
	"github.com/ThreeDotsLabs/watermill/message/router/middleware"
	"github.com/ThreeDotsLabs/watermill/message/router/plugin"
	"go.uber.org/zap"
	"profile/internal/config"
	"profile/internal/log"
	"profile/internal/schema"
	"time"
)

// ProfileContext
// @Description:
// @Author xzx 2023-08-11 22:21:41
type ProfileContext struct {
	// Properties that can be called by inherited subclasses
	Status int
	Ctx    context.Context

	Router *message.Router
	Event  schema.Event

	AppID         string // API 上报
	FetchScenario string // API 上报
}

// NewProfileContext
// @Description
// @Author xzx 2023-08-11 22:49:00
// @Return *ProfileContext
func NewProfileContext() *ProfileContext {
	profileCtx := &ProfileContext{
		Ctx: context.Background(),
	}
	profileCtx.init()
	return profileCtx
}

// init
// @Description 初始化
// @Author xzx 2023-08-11 22:22:01
func (profileCtx *ProfileContext) init() {
	logger := watermill.NewStdLogger(false, false)
	saramaSubscriberConfig := kafka.DefaultSaramaSubscriberConfig()
	saramaSubscriberConfig.Consumer.Offsets.Initial = sarama.OffsetOldest
	subscriber, err := kafka.NewSubscriber(
		kafka.SubscriberConfig{
			Brokers:               []string{config.Profile.GetString("kafka.bootstrap")},
			Unmarshaler:           kafka.DefaultMarshaler{},
			OverwriteSaramaConfig: saramaSubscriberConfig,
			ConsumerGroup:         config.Profile.GetString("kafka.group"),
		},
		logger,
	)
	if err != nil {
		log.Logger.Error("creates a new Kafka Subscriber error", zap.Error(err))
	}

	router, err := message.NewRouter(message.RouterConfig{}, logger)
	if err != nil {
		log.Logger.Error("creates a new Router with given configuration error", zap.Error(err))
	}

	router.AddPlugin(plugin.SignalsHandler)
	router.AddMiddleware(
		middleware.CorrelationID,
		middleware.Retry{
			MaxRetries:      3,
			InitialInterval: time.Millisecond * 100,
			Logger:          logger,
		}.Middleware,
		middleware.Recoverer,
	)

	topic := "to_analyzer__0.PERF_CRASH"
	router.AddNoPublisherHandler("WriteKafka", topic, subscriber, profileCtx.WriteKafka).
		AddMiddleware(
			profileCtx.UnpackKafkaMessage,
			profileCtx.InitPerformanceEvent,
			profileCtx.AnalyzeEvent,
		)

	profileCtx.Router = router
}

// Run
// @Description
// @Author xzx 2023-08-12 13:52:53
func (profileCtx *ProfileContext) Run() {
	// router.Run contains defer cancel()
	if err := profileCtx.Router.Run(profileCtx.Ctx); err != nil {
		log.Logger.Error("runs all plugins and handlers and starts subscribing to provided topics error", zap.Error(err))
	}
}

func (profileCtx *ProfileContext) Done() <-chan struct{} {
	return profileCtx.Ctx.Done()
}

func (profileCtx *ProfileContext) Err() error {
	return profileCtx.Ctx.Err()
}

func (profileCtx *ProfileContext) Deadline() (deadline time.Time, ok bool) {
	return profileCtx.Ctx.Deadline()
}

func (profileCtx *ProfileContext) Value(key any) any {
	return profileCtx.Ctx.Value(key)
}

【测试】前 3 个阶段处理为 Middleware，最后一个阶段为 Handler

// Package consumer
// @Author xzx 2023/8/12 10:01:00
package consumer

import (
	"encoding/json"
	"github.com/ThreeDotsLabs/watermill/message"
	"github.com/segmentio/kafka-go"
	"go.uber.org/zap"
	"profile/internal/connector"
	"profile/internal/log"
	"profile/internal/schema/performance"
	"profile/internal/state"
)

// UnpackKafkaMessage
// @Description
// @Author xzx 2023-08-12 12:27:30
// @Param h
// @Return message.HandlerFunc
func (profileCtx *ProfileContext) UnpackKafkaMessage(h message.HandlerFunc) message.HandlerFunc {
	return func(message *message.Message) ([]*message.Message, error) {
		// 反序列化，存入通用结构体
		if contextErr := json.Unmarshal(message.Payload, &profileCtx.Event); contextErr != nil {
			profileCtx.Status = state.StatusUnmarshalError
			return h(message)
		}
		log.Logger.Info("[UnpackKafkaItem] unpack kafka item success", zap.Any("event", profileCtx.Event))

		message.SetContext(profileCtx)
		return h(message)
	}
}

// InitPerformanceEvent
// @Description
// @Author xzx 2023-08-12 12:27:35
// @Param h
// @Return message.HandlerFunc
func (profileCtx *ProfileContext) InitPerformanceEvent(h message.HandlerFunc) message.HandlerFunc {
	return func(message *message.Message) ([]*message.Message, error) {
		profileCtx = message.Context().(*ProfileContext)

		event, contextErr := performance.EventFactory(profileCtx.Event.Category, profileCtx.Event.Dimensions, profileCtx.Event.Values)
		if contextErr != nil {
			profileCtx.Status = state.StatusEventFactoryError
			return h(message)
		}
		log.Logger.Info("[InitPerformanceEvent] init performance event success", zap.Any("event", profileCtx.Event))
		profileCtx.Event.ProfileData = event

		message.SetContext(profileCtx)
		return h(message)
	}
}

// AnalyzeEvent
// @Description
// @Author xzx 2023-08-12 12:27:38
// @Param h
// @Return message.HandlerFunc
func (profileCtx *ProfileContext) AnalyzeEvent(h message.HandlerFunc) message.HandlerFunc {
	return func(message *message.Message) ([]*message.Message, error) {
		profileCtx = message.Context().(*ProfileContext)

		contextErr := profileCtx.Event.ProfileData.Analyze()
		if contextErr != nil {
			profileCtx.Status = state.StatusAnalyzeError
			return h(message)
		}
		log.Logger.Info("[AnalyzeEvent] analyze event success", zap.Any("event", profileCtx.Event))
		// clear dimensions and values
		profileCtx.Event.Dimensions = nil
		profileCtx.Event.Values = nil

		message.SetContext(profileCtx)
		return h(message)
	}
}

// WriteKafka
// @Description
// @Author xzx 2023-08-11 22:30:47
// @Param msg
// @Return contextErr
func (profileCtx *ProfileContext) WriteKafka(msg *message.Message) (contextErr error) {
	profileCtx = msg.Context().(*ProfileContext)

	toWriteBytes, contextErr := json.Marshal(profileCtx.Event)
	if contextErr != nil {
		profileCtx.Status = state.StatusUnmarshalError
		return
	}
	topic := connector.GetTopic(profileCtx.Event.Category)
	contextErr = connector.GetProducer().WriteMessages(profileCtx.Ctx, kafka.Message{
		Topic: topic,
		Key:   []byte(profileCtx.Event.ID),
		Value: toWriteBytes,
	})
	if contextErr != nil {
		profileCtx.Status = state.StatusWriteKafkaError
		return
	}
	log.Logger.Info("[WriteKafka] write kafka success", zap.String("topic", topic), zap.String("id", profileCtx.Event.ID), zap.String("msg", string(toWriteBytes)))
	return
}

可以实现正常的效果

Router

目前的 topic 是固定写死的，要考虑正则表达式，将不同 topic 的共有逻辑抽出为 Middleware，特定逻辑抽出为 Handler
消息处理似乎不是并发的

pub/sub kafka-go

custom pub/sub
Kafka Pub/Sub for the Watermill project, based on Shopify’s Sarama
qiulin/watermill-kafkago: Kafka Pub/Sub for the Watermill project, based on segmentio/kafka-go (github.com)