client.go

package main

import (
	"flag"
	"log"
	"sync"
	"time"

	wwr "github.com/qbeon/webwire-go"

	wwrclt "github.com/qbeon/webwire-go/client"
)

var serverAddr = flag.String("addr", ":8081", "server address")
var counterTarget = flag.Uint("n", 6, "number of signals to listen for")

// PubSubClient implements the wwrclt.Implementation interface
type PubSubClient struct {
	connection    *wwrclt.Client
	target        uint
	counter       uint
	targetReached sync.WaitGroup
}

// NewPubSubClient constructs and returns a new pub-sub client instance
func NewPubSubClient(serverAddr string, counterTarget uint) *PubSubClient {
	newPubSubClient := &PubSubClient{
		target:        counterTarget,
		counter:       0,
		targetReached: sync.WaitGroup{},
	}

	newPubSubClient.targetReached.Add(int(counterTarget))

	// Initialize connection
	newPubSubClient.connection = wwrclt.NewClient(
		serverAddr,
		newPubSubClient,
		wwrclt.Options{
			// Default timeout for timed requests
			DefaultRequestTimeout: 10 * time.Second,
			ReconnectionInterval:  2 * time.Second,
		},
	)

	return newPubSubClient
}

// OnDisconnected implements the wwrclt.Implementation interface
func (clt *PubSubClient) OnDisconnected() {}

// OnSessionClosed implements the wwrclt.Implementation interface
func (clt *PubSubClient) OnSessionClosed() {}

// OnSessionCreated implements the wwrclt.Implementation interface
func (clt *PubSubClient) OnSessionCreated(_ *wwr.Session) {}

// OnSignal implements the wwrclt.Implementation interface
func (clt *PubSubClient) OnSignal(message wwr.Payload) {
	clt.counter++
	log.Printf(
		"Signal %d of %d received: %s",
		clt.counter,
		clt.target,
		string(message.Data),
	)
	clt.targetReached.Done()
}

// AwaitCounterTargetReached blocks the calling goroutine until the counter
// target is reached
func (clt *PubSubClient) AwaitCounterTargetReached() {
	clt.targetReached.Wait()
}

func main() {
	// Parse command line arguments
	flag.Parse()

	// Initialize a new pub-sub client instance
	client := NewPubSubClient(*serverAddr, *counterTarget)

	// Wait until N signals are received before disconnecting
	client.AwaitCounterTargetReached()
}