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knotclient: introduce event consumer #226

merged

opened by

oppi.li 6 months ago targeting master from push-lrzzmtxokrxw

generic websocket consumer for one or more event streams from knots

Signed-off-by: oppiliappan me@oppi.li

options

unified split

Changed files

+228

cmd

eventconsumer

main.go

knotclient

events.go

+47

cmd/eventconsumer/main.go

···

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       package main

     

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       import (

     

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       	"context"

     

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       	"flag"

     

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       	"fmt"

     

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       	"strings"

     

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       	"time"

     

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       	"tangled.sh/tangled.sh/core/knotclient"

     

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       )

     

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       func main() {

     

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       	sourcesFlag := flag.String("sources", "", "list of wss sources")

     

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       	retryFlag := flag.Duration("retry", 1*time.Minute, "retry interval")

     

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       	maxRetryFlag := flag.Duration("max-retry", 30*time.Minute, "max retry interval")

     

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       	workerCount := flag.Int("workers", 10, "goroutine pool size")

     

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       	flag.Parse()

     

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       	if *sourcesFlag == "" {

     

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       		fmt.Println("error: -sources is required")

     

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       		flag.Usage()

     

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       		return

     

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       	}

     

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       	sources := strings.Split(*sourcesFlag, ",")

     

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       	consumer := knotclient.NewEventConsumer(knotclient.ConsumerConfig{

     

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       		Sources:          sources,

     

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       		ProcessFunc:      processEvent,

     

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       		RetryInterval:    *retryFlag,

     

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       		MaxRetryInterval: *maxRetryFlag,

     

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       		WorkerCount:      *workerCount,

     

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       	})

     

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       	ctx, cancel := context.WithCancel(context.Background())

     

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       	consumer.Start(ctx)

     

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       	time.Sleep(1 * time.Hour)

     

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       	cancel()

     

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       	consumer.Stop()

     

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       }

     

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       func processEvent(source string, msg []byte) error {

     

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       	fmt.Printf("From %s: %s\n", source, string(msg))

     

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       	return nil

     

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       }

+181

knotclient/events.go

···

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       package knotclient

     

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       import (

     

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       	"context"

     

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       	"log/slog"

     

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       	"math/rand"

     

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       	"net/url"

     

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       	"sync"

     

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       	"time"

     

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       	"tangled.sh/tangled.sh/core/log"

     

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       	"github.com/gorilla/websocket"

     

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       )

     

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       type ProcessFunc func(source string, message []byte) error

     

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       type ConsumerConfig struct {

     

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       	Sources           []string

     

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       	ProcessFunc       ProcessFunc

     

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       	RetryInterval     time.Duration

     

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       	MaxRetryInterval  time.Duration

     

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       	ConnectionTimeout time.Duration

     

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       	WorkerCount       int

     

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       	Logger            *slog.Logger

     

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       }

     

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       type EventConsumer struct {

     

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       	cfg        ConsumerConfig

     

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       	wg         sync.WaitGroup

     

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       	dialer     *websocket.Dialer

     

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       	connMap    sync.Map

     

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       	jobQueue   chan job

     

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       	logger     *slog.Logger

     

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       	randSource *rand.Rand

     

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       }

     

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       type job struct {

     

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       	source  string

     

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       	message []byte

     

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       }

     

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       func NewEventConsumer(cfg ConsumerConfig) *EventConsumer {

     

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       	if cfg.RetryInterval == 0 {

     

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       		cfg.RetryInterval = 15 * time.Minute

     

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       	}

     

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       	if cfg.ConnectionTimeout == 0 {

     

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       		cfg.ConnectionTimeout = 10 * time.Second

     

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       	}

     

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       	if cfg.WorkerCount <= 0 {

     

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       		cfg.WorkerCount = 5

     

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       	}

     

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       	if cfg.MaxRetryInterval == 0 {

     

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       		cfg.MaxRetryInterval = 1 * time.Hour

     

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       	}

     

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       	if cfg.Logger == nil {

     

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       		cfg.Logger = log.New("eventconsumer")

     

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       	}

     

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       	return &EventConsumer{

     

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       		cfg:        cfg,

     

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       		dialer:     websocket.DefaultDialer,

     

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       		jobQueue:   make(chan job, 100), // buffered job queue

     

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       		logger:     cfg.Logger,

     

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       		randSource: rand.New(rand.NewSource(time.Now().UnixNano())),

     

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       	}

     

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       }

     

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       func (c *EventConsumer) Start(ctx context.Context) {

     

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       	// start workers

     

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       	for range c.cfg.WorkerCount {

     

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       		c.wg.Add(1)

     

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       		go c.worker(ctx)

     

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       	}

     

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       	// start streaming

     

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       	for _, source := range c.cfg.Sources {

     

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       		c.wg.Add(1)

     

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       		go c.startConnectionLoop(ctx, source)

     

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       	}

     

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       }

     

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       func (c *EventConsumer) Stop() {

     

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       	c.connMap.Range(func(_, val any) bool {

     

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       		if conn, ok := val.(*websocket.Conn); ok {

     

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       			conn.Close()

     

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       		}

     

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       		return true

     

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       	})

     

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       	c.wg.Wait()

     

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       	close(c.jobQueue)

     

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       }

     

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       func (c *EventConsumer) worker(ctx context.Context) {

     

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       	defer c.wg.Done()

     

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       	for {

     

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       		select {

     

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       		case <-ctx.Done():

     

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       			return

     

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       		case j, ok := <-c.jobQueue:

     

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       			if !ok {

     

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       				return

     

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       			}

     

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       			if err := c.cfg.ProcessFunc(j.source, j.message); err != nil {

     

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       				c.logger.Error("error processing message", "source", j.source, "err", err)

     

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       			}

     

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       		}

     

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       	}

     

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       }

     

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       func (c *EventConsumer) startConnectionLoop(ctx context.Context, source string) {

     

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       	defer c.wg.Done()

     

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       	retryInterval := c.cfg.RetryInterval

     

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       	for {

     

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       		select {

     

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       		case <-ctx.Done():

     

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       			return

     

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       		default:

     

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       			err := c.runConnection(ctx, source)

     

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       			if err != nil {

     

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       				c.logger.Error("connection failed", "source", source, "err", err)

     

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       			}

     

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       			// apply jitter

     

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       			jitter := time.Duration(c.randSource.Int63n(int64(retryInterval) / 5))

     

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       			delay := retryInterval + jitter

     

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       			if retryInterval < c.cfg.MaxRetryInterval {

     

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       				retryInterval *= 2

     

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       				if retryInterval > c.cfg.MaxRetryInterval {

     

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       					retryInterval = c.cfg.MaxRetryInterval

     

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       				}

     

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       			}

     

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       			c.logger.Info("retrying connection", "source", source, "delay", delay)

     

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       			select {

     

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       			case <-time.After(delay):

     

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       			case <-ctx.Done():

     

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       				return

     

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       			}

     

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       		}

     

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       	}

     

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       }

     

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       func (c *EventConsumer) runConnection(ctx context.Context, source string) error {

     

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       	connCtx, cancel := context.WithTimeout(ctx, c.cfg.ConnectionTimeout)

     

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       	defer cancel()

     

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       	u, err := url.Parse(source)

     

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       	if err != nil {

     

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       		return err

     

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       	}

     

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       	conn, _, err := c.dialer.DialContext(connCtx, u.String(), nil)

     

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       	if err != nil {

     

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       		return err

     

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       	}

     

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       	defer conn.Close()

     

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       	c.connMap.Store(source, conn)

     

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       	defer c.connMap.Delete(source)

     

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       	c.logger.Info("connected", "source", source)

     

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       	for {

     

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       		select {

     

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       		case <-ctx.Done():

     

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       			return nil

     

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       		default:

     

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       			msgType, msg, err := conn.ReadMessage()

     

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       			if err != nil {

     

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       				return err

     

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       			}

     

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       			if msgType != websocket.TextMessage {

     

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       				continue

     

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       			}

     

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       			select {

     

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       			case c.jobQueue <- job{source: source, message: msg}:

     

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       			case <-ctx.Done():

     

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       				return nil

     

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       			}

     

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       		}

     

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       	}

     

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       }