add example of using Pulsar with testcontainers-go (#597)

* add example of using Pulsar with testcontainers-go

* remove use of gomega from pulsar example, add pulsar example to mkdocs config

* extract pulsar setup to own method

* tweak wait strategy to prevent flakiness in pulsar tests

docs/examples/pulsar.md

@@ -0,0 +1,134 @@
+# Pulsar
+
+```go
+package main
+
+import (
+	"context"
+	"fmt"
+	"io"
+	"testing"
+	"time"
+
+	"github.com/apache/pulsar-client-go/pulsar"
+	"github.com/testcontainers/testcontainers-go"
+	"github.com/testcontainers/testcontainers-go/wait"
+)
+
+type pulsarContainer struct {
+	testcontainers.Container
+	URI string
+}
+
+func setupPulsar(ctx context.Context) (*pulsarContainer, error) {
+	matchAdminResponse := func(r io.Reader) bool {
+		respBytes, _ := io.ReadAll(r)
+		resp := string(respBytes)
+		return resp == `["standalone"]`
+	}
+	pulsarRequest := testcontainers.ContainerRequest{
+		Image:        "docker.io/apachepulsar/pulsar:2.10.2",
+		ExposedPorts: []string{"6650/tcp", "8080/tcp"},
+		WaitingFor: wait.ForAll(
+			wait.ForHTTP("/admin/v2/clusters").WithPort("8080/tcp").WithResponseMatcher(matchAdminResponse),
+			wait.ForLog("Successfully updated the policies on namespace public/default"),
+		),
+		Cmd: []string{
+			"/bin/bash",
+			"-c",
+			"/pulsar/bin/apply-config-from-env.py /pulsar/conf/standalone.conf && bin/pulsar standalone --no-functions-worker -nss",
+		},
+	}
+	c, err := testcontainers.GenericContainer(ctx, testcontainers.GenericContainerRequest{
+		ContainerRequest: pulsarRequest,
+		Started:          true,
+	})
+	if err != nil {
+		return nil, err
+	}
+
+	c.StartLogProducer(ctx)
+	defer c.StopLogProducer()
+	lc := logConsumer{}
+	c.FollowOutput(&lc)
+
+	pulsarPort, err := c.MappedPort(ctx, "6650/tcp")
+	if err != nil {
+		return nil, err
+	}
+
+	return &pulsarContainer{
+		Container: c,
+		URI:       fmt.Sprintf("pulsar://127.0.0.1:%v", pulsarPort.Int()),
+	}, nil
+}
+
+func TestPulsar(t *testing.T) {
+	ctx, cancel := context.WithCancel(context.Background())
+	defer cancel()
+
+	c, err := setupPulsar(ctx)
+	if err != nil {
+		t.Fatal(err)
+	}
+	t.Cleanup(func() { c.Container.Terminate(ctx) })
+
+	pc, err := pulsar.NewClient(pulsar.ClientOptions{
+		URL:               c.URI,
+		OperationTimeout:  30 * time.Second,
+		ConnectionTimeout: 30 * time.Second,
+	})
+	if err != nil {
+		t.Fatal(err)
+	}
+	t.Cleanup(func() { pc.Close() })
+
+	consumer, err := pc.Subscribe(pulsar.ConsumerOptions{
+		Topic:            "test-topic",
+		SubscriptionName: "pulsar-test",
+		Type:             pulsar.Exclusive,
+	})
+	if err != nil {
+		t.Fatal(err)
+	}
+	t.Cleanup(func() { consumer.Close() })
+
+	msgChan := make(chan []byte)
+	go func() {
+		msg, err := consumer.Receive(ctx)
+		if err != nil {
+			fmt.Println("failed to receive message", err)
+			return
+		}
+		msgChan <- msg.Payload()
+		consumer.Ack(msg)
+	}()
+
+	producer, err := pc.CreateProducer(pulsar.ProducerOptions{
+		Topic: "test-topic",
+	})
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	producer.Send(ctx, &pulsar.ProducerMessage{
+		Payload: []byte("hello world"),
+	})
+
+	ticker := time.NewTicker(1 * time.Minute)
+	select {
+	case <-ticker.C:
+		t.Fatal("did not receive message in time")
+	case msg := <-msgChan:
+		if string(msg) != "hello world" {
+			t.Fatal("received unexpected message bytes")
+		}
+	}
+}
+
+type logConsumer struct{}
+
+func (lc *logConsumer) Accept(l testcontainers.Log) {
+	fmt.Print(string(l.Content))
+}
+```

mkdocs.yml

@@ -50,6 +50,7 @@ nav:
           - examples/cockroachdb.md
           - examples/nginx.md
           - examples/redis.md
+          - examples/pulsar.md
     - System Requirements:
           - system_requirements/index.md
           - system_requirements/using_colima.md