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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

+238

cmd

eventconsumer

main.go

knotclient

events.go

+44

cmd/eventconsumer/main.go

···

       1
       +
       package main

     

       2
       +
       

     

       3
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       import (

     

       4
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       	"flag"

     

       5
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       	"fmt"

     

       6
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       	"strings"

     

       7
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       	"time"

     

       8
       +
       

     

       9
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       	"tangled.sh/tangled.sh/core/knotclient"

     

       10
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       )

     

       11
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       12
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       func main() {

     

       13
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       	sourcesFlag := flag.String("sources", "", "list of wss sources")

     

       14
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       	retryFlag := flag.Duration("retry", 1*time.Minute, "retry interval")

     

       15
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       	maxRetryFlag := flag.Duration("max-retry", 30*time.Minute, "max retry interval")

     

       16
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       	workerCount := flag.Int("workers", 10, "goroutine pool size")

     

       17
       +
       

     

       18
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       	flag.Parse()

     

       19
       +
       

     

       20
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       	if *sourcesFlag == "" {

     

       21
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       		fmt.Println("error: -sources is required")

     

       22
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       		flag.Usage()

     

       23
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       		return

     

       24
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       	}

     

       25
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       26
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       	sources := strings.Split(*sourcesFlag, ",")

     

       27
       +
       

     

       28
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       	consumer := knotclient.NewEventConsumer(knotclient.ConsumerConfig{

     

       29
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       		Sources:          sources,

     

       30
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       		ProcessFunc:      processEvent,

     

       31
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       		RetryInterval:    *retryFlag,

     

       32
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       		MaxRetryInterval: *maxRetryFlag,

     

       33
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       		WorkerCount:      *workerCount,

     

       34
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       	})

     

       35
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       36
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       	consumer.Start()

     

       37
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       	time.Sleep(1 * time.Hour)

     

       38
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       	consumer.Stop()

     

       39
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       }

     

       40
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       41
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       func processEvent(source string, msg []byte) error {

     

       42
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       	fmt.Printf("From %s: %s\n", source, string(msg))

     

       43
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       	return nil

     

       44
       +
       }

+194

knotclient/events.go

···

       1
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       package knotclient

     

       2
       +
       

     

       3
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       import (

     

       4
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       	"context"

     

       5
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       	"log/slog"

     

       6
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       	"math/rand"

     

       7
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       	"net/url"

     

       8
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       	"sync"

     

       9
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       	"time"

     

       10
       +
       

     

       11
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       	"tangled.sh/tangled.sh/core/log"

     

       12
       +
       

     

       13
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       	"github.com/gorilla/websocket"

     

       14
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       )

     

       15
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       16
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       type ProcessFunc func(source string, message []byte) error

     

       17
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       18
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       type ConsumerConfig struct {

     

       19
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       	Sources           []string

     

       20
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       	ProcessFunc       ProcessFunc

     

       21
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       	RetryInterval     time.Duration

     

       22
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       	MaxRetryInterval  time.Duration

     

       23
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       	ConnectionTimeout time.Duration

     

       24
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       	WorkerCount       int

     

       25
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       	Logger            *slog.Logger

     

       26
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       }

     

       27
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       28
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       type EventConsumer struct {

     

       29
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       	cfg        ConsumerConfig

     

       30
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       	ctx        context.Context

     

       31
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       	cancel     context.CancelFunc

     

       32
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       	wg         sync.WaitGroup

     

       33
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       	dialer     *websocket.Dialer

     

       34
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       	connMap    sync.Map

     

       35
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       	jobQueue   chan job

     

       36
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       	logger     *slog.Logger

     

       37
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       	randSource *rand.Rand

     

       38
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       }

     

       39
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       40
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       type job struct {

     

       41
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       	source  string

     

       42
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       	message []byte

     

       43
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       }

     

       44
       +
       

     

       45
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       func NewEventConsumer(cfg ConsumerConfig) *EventConsumer {

     

       46
       +
       	if cfg.RetryInterval == 0 {

     

       47
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       		cfg.RetryInterval = 15 * time.Minute

     

       48
       +
       	}

     

       49
       +
       	if cfg.ConnectionTimeout == 0 {

     

       50
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       		cfg.ConnectionTimeout = 10 * time.Second

     

       51
       +
       	}

     

       52
       +
       	if cfg.WorkerCount <= 0 {

     

       53
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       		cfg.WorkerCount = 5

     

       54
       +
       	}

     

       55
       +
       	if cfg.MaxRetryInterval == 0 {

     

       56
       +
       		cfg.MaxRetryInterval = 1 * time.Hour

     

       57
       +
       	}

     

       58
       +
       	if cfg.Logger == nil {

     

       59
       +
       		cfg.Logger = log.New("eventconsumer")

     

       60
       +
       	}

     

       61
       +
       

     

       62
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       	ctx, cancel := context.WithCancel(context.Background())

     

       63
       +
       

     

       64
       +
       	return &EventConsumer{

     

       65
       +
       		cfg:        cfg,

     

       66
       +
       		ctx:        ctx,

     

       67
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       		cancel:     cancel,

     

       68
       +
       		dialer:     websocket.DefaultDialer,

     

       69
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       		jobQueue:   make(chan job, 100), // buffered job queue

     

       70
       +
       		logger:     cfg.Logger,

     

       71
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       		randSource: rand.New(rand.NewSource(time.Now().UnixNano())),

     

       72
       +
       	}

     

       73
       +
       }

     

       74
       +
       

     

       75
       +
       func (c *EventConsumer) Start() {

     

       76
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       	// start workers

     

       77
       +
       	for range c.cfg.WorkerCount {

     

       78
       +
       		c.wg.Add(1)

     

       79
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       		go c.worker()

     

       80
       +
       	}

     

       81
       +
       

     

       82
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       	// start streaming

     

       83
       +
       	for _, source := range c.cfg.Sources {

     

       84
       +
       		c.wg.Add(1)

     

       85
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       		go c.startConnectionLoop(source)

     

       86
       +
       	}

     

       87
       +
       }

     

       88
       +
       

     

       89
       +
       func (c *EventConsumer) Stop() {

     

       90
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       	c.cancel()

     

       91
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       	c.connMap.Range(func(_, val any) bool {

     

       92
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       		if conn, ok := val.(*websocket.Conn); ok {

     

       93
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       			conn.Close()

     

       94
       +
       		}

     

       95
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       		return true

     

       96
       +
       	})

     

       97
       +
       	c.wg.Wait()

     

       98
       +
       	close(c.jobQueue)

     

       99
       +
       }

     

       100
       +
       

     

       101
       +
       func (c *EventConsumer) worker() {

     

       102
       +
       	defer c.wg.Done()

     

       103
       +
       	for {

     

       104
       +
       		select {

     

       105
       +
       		case <-c.ctx.Done():

     

       106
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       			return

     

       107
       +
       		case j, ok := <-c.jobQueue:

     

       108
       +
       			if !ok {

     

       109
       +
       				return

     

       110
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       			}

     

       111
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       			if err := c.cfg.ProcessFunc(j.source, j.message); err != nil {

     

       112
       +
       				c.logger.Error("error processing message", "source", j.source, "err", err)

     

       113
       +
       			}

     

       114
       +
       		}

     

       115
       +
       	}

     

       116
       +
       }

     

       117
       +
       

     

       118
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       func (c *EventConsumer) startConnectionLoop(source string) {

     

       119
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       	defer c.wg.Done()

     

       120
       +
       

     

       121
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       	retryInterval := c.cfg.RetryInterval

     

       122
       +
       

     

       123
       +
       	for {

     

       124
       +
       		select {

     

       125
       +
       		case <-c.ctx.Done():

     

       126
       +
       			return

     

       127
       +
       		default:

     

       128
       +
       			err := c.runConnection(source)

     

       129
       +
       			if err != nil {

     

       130
       +
       				c.logger.Error("connection failed", "source", source, "err", err)

     

       131
       +
       			}

     

       132
       +
       

     

       133
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       			// Apply jitter

     

       134
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       			jitter := time.Duration(c.randSource.Int63n(int64(retryInterval) / 5))

     

       135
       +
       			delay := retryInterval + jitter

     

       136
       +
       

     

       137
       +
       			if retryInterval < c.cfg.MaxRetryInterval {

     

       138
       +
       				retryInterval *= 2

     

       139
       +
       				if retryInterval > c.cfg.MaxRetryInterval {

     

       140
       +
       					retryInterval = c.cfg.MaxRetryInterval

     

       141
       +
       				}

     

       142
       +
       			}

     

       143
       +
       

     

       144
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       			c.logger.Info("retrying connection", "source", source, "delay", delay)

     

       145
       +
       			select {

     

       146
       +
       			case <-time.After(delay):

     

       147
       +
       			case <-c.ctx.Done():

     

       148
       +
       				return

     

       149
       +
       			}

     

       150
       +
       		}

     

       151
       +
       	}

     

       152
       +
       }

     

       153
       +
       

     

       154
       +
       func (c *EventConsumer) runConnection(source string) error {

     

       155
       +
       	ctx, cancel := context.WithTimeout(c.ctx, c.cfg.ConnectionTimeout)

     

       156
       +
       	defer cancel()

     

       157
       +
       

     

       158
       +
       	u, err := url.Parse(source)

     

       159
       +
       	if err != nil {

     

       160
       +
       		return err

     

       161
       +
       	}

     

       162
       +
       

     

       163
       +
       	conn, _, err := c.dialer.DialContext(ctx, u.String(), nil)

     

       164
       +
       	if err != nil {

     

       165
       +
       		return err

     

       166
       +
       	}

     

       167
       +
       	defer conn.Close()

     

       168
       +
       

     

       169
       +
       	c.connMap.Store(source, conn)

     

       170
       +
       	defer c.connMap.Delete(source)

     

       171
       +
       

     

       172
       +
       	c.logger.Info("connected", "source", source)

     

       173
       +
       

     

       174
       +
       	for {

     

       175
       +
       		select {

     

       176
       +
       		case <-c.ctx.Done():

     

       177
       +
       			return nil

     

       178
       +
       		default:

     

       179
       +
       			msgType, msg, err := conn.ReadMessage()

     

       180
       +
       			if err != nil {

     

       181
       +
       				return err

     

       182
       +
       			}

     

       183
       +
       			if msgType != websocket.TextMessage {

     

       184
       +
       				continue

     

       185
       +
       			}

     

       186
       +
       

     

       187
       +
       			select {

     

       188
       +
       			case c.jobQueue <- job{source: source, message: msg}:

     

       189
       +
       			case <-c.ctx.Done():

     

       190
       +
       				return nil

     

       191
       +
       			}

     

       192
       +
       		}

     

       193
       +
       	}

     

       194
       +
       }