Enabling Pub/Sub to send and receive from multiple topics and subscri…

…ptions. (cloudevents#171)

Signed-off-by: Scott Nichols <nicholss@google.com>

cmd/samples/pubsub/converter/receiver/main.go

@@ -10,10 +10,17 @@ import (
 	"github.com/cloudevents/sdk-go"
 	"github.com/cloudevents/sdk-go/pkg/cloudevents/transport"
 	"github.com/cloudevents/sdk-go/pkg/cloudevents/transport/pubsub"
+	pscontext "github.com/cloudevents/sdk-go/pkg/cloudevents/transport/pubsub/context"
 	"github.com/google/uuid"
 	"github.com/kelseyhightower/envconfig"
 )
 
+/*
+
+curl -X POST -H "Content-Type: application/json"  -d '{"id":123,"message":"hello world"}' http://localhost:8080
+
+*/
+
 type envConfig struct {
 	ProjectID      string `envconfig:"GOOGLE_CLOUD_PROJECT"`
 	TopicID        string `envconfig:"PUBSUB_TOPIC" default:"demo_cloudevents" required:"true"`
@@ -44,7 +51,7 @@ func convert(ctx context.Context, m transport.Message, err error) (*cloudevents.
 	log.Printf("trying to recover from %v", err)
 
 	if msg, ok := m.(*pubsub.Message); ok {
-		tx := pubsub.TransportContextFrom(ctx)
+		tx := pscontext.TransportContextFrom(ctx)
 		// Make a new event and convert the message payload.
 		event := cloudevents.NewEvent()
 		event.SetSource("github.com/cloudevents/cmd/samples/pubsub/converter/receiver")
@@ -82,9 +89,3 @@ func main() {
 	log.Printf("will listen on %s/%s\n", env.TopicID, env.SubscriptionID)
 	log.Fatalf("failed to start receiver: %s", c.StartReceiver(ctx, gotEvent))
 }
-
-/*
-
-curl -X POST -H "Content-Type: application/json"  -d '{"id":123,"message":"hello world"}' http://localhost:8080
-
-*/

cmd/samples/pubsub/converter/sender/main.go

@@ -10,6 +10,14 @@ import (
 	"github.com/kelseyhightower/envconfig"
 )
 
+/*
+
+To view: gcloud pubsub subscriptions pull --auto-ack foo
+
+To post: gcloud pubsub topics publish demo_cloudevents --message '{"id":123,"message":"hi from the terminal"}'
+
+*/
+
 type envConfig struct {
 	ProjectID string `envconfig:"GOOGLE_CLOUD_PROJECT" required:"true"`
 
@@ -69,11 +77,3 @@ func main() {
 		log.Printf("Could not publish message: %v", err)
 	}
 }
-
-/*
-
-To view: gcloud pubsub subscriptions pull --auto-ack foo
-
-To post: gcloud pubsub topics publish demo_cloudevents --message '{"id":123,"message":"hi from the terminal"}'
-
-*/

cmd/samples/pubsub/multireceiver/main.go

@@ -0,0 +1,89 @@
+package main
+
+import (
+	"context"
+	"fmt"
+	"log"
+	"os"
+	"strings"
+
+	"github.com/cloudevents/sdk-go"
+	"github.com/cloudevents/sdk-go/pkg/cloudevents/client"
+	cepubsub "github.com/cloudevents/sdk-go/pkg/cloudevents/transport/pubsub"
+	pscontext "github.com/cloudevents/sdk-go/pkg/cloudevents/transport/pubsub/context"
+	"github.com/kelseyhightower/envconfig"
+)
+
+/*
+
+To setup:
+
+gcloud pubsub topics create demo_cloudevents
+gcloud pubsub subscriptions create foo --topic=demo_cloudevents
+
+To test:
+
+gcloud pubsub topics publish demo_cloudevents --message='{"Hello": "world"}'
+
+To fix a bad message:
+
+gcloud pubsub subscriptions pull --auto-ack foo
+
+*/
+
+type envConfig struct {
+	ProjectID string `envconfig:"GOOGLE_CLOUD_PROJECT"`
+
+	SubscriptionIDs string `envconfig:"PUBSUB_SUBSCRIPTIONS" default:"foo" required:"true"`
+}
+
+type Example struct {
+	Sequence int    `json:"id"`
+	Message  string `json:"message"`
+}
+
+func receive(ctx context.Context, event cloudevents.Event, resp *cloudevents.EventResponse) error {
+	fmt.Printf("Event Context: %+v\n", event.Context)
+
+	fmt.Printf("Transport Context: %+v\n", pscontext.TransportContextFrom(ctx))
+
+	data := &Example{}
+	if err := event.DataAs(data); err != nil {
+		fmt.Printf("Got Data Error: %s\n", err.Error())
+	}
+	fmt.Printf("Data: %+v\n", data)
+
+	fmt.Printf("----------------------------\n")
+	return nil
+}
+
+func main() {
+	ctx := context.Background()
+
+	var env envConfig
+	if err := envconfig.Process("", &env); err != nil {
+		log.Printf("[ERROR] Failed to process env var: %s", err)
+		os.Exit(1)
+	}
+
+	var opts []cepubsub.Option
+	opts = append(opts, cepubsub.WithProjectID(env.ProjectID))
+	for _, subscription := range strings.Split(env.SubscriptionIDs, ",") {
+		opts = append(opts, cepubsub.WithSubscriptionID(subscription))
+	}
+
+	t, err := cepubsub.New(context.Background(), opts...)
+	if err != nil {
+		log.Fatalf("failed to create pubsub transport, %s", err.Error())
+	}
+	c, err := client.New(t)
+	if err != nil {
+		log.Fatalf("failed to create client, %s", err.Error())
+	}
+
+	log.Println("Created client, listening...")
+
+	if err := c.StartReceiver(ctx, receive); err != nil {
+		log.Fatalf("failed to start pubsub receiver, %s", err.Error())
+	}
+}

cmd/samples/pubsub/multisender/main.go

@@ -0,0 +1,78 @@
+package main
+
+import (
+	"context"
+	"log"
+	"os"
+	"strings"
+
+	"github.com/kelseyhightower/envconfig"
+
+	"github.com/cloudevents/sdk-go"
+	cecontext "github.com/cloudevents/sdk-go/pkg/cloudevents/context"
+	cepubsub "github.com/cloudevents/sdk-go/pkg/cloudevents/transport/pubsub"
+)
+
+/*
+
+gcloud pubsub topics create ce1
+gcloud pubsub topics create ce2
+gcloud pubsub topics create ce3
+
+gcloud pubsub subscriptions create ce1_sub --topic=ce1
+gcloud pubsub subscriptions create ce2_sub --topic=ce2
+gcloud pubsub subscriptions create ce3_sub --topic=ce3
+
+*/
+
+type envConfig struct {
+	ProjectID string `envconfig:"GOOGLE_CLOUD_PROJECT" required:"true"`
+
+	TopicIDs string `envconfig:"PUBSUB_TOPICS" default:"demo_cloudevents" required:"true"`
+}
+
+// Basic data struct.
+type Example struct {
+	Sequence int    `json:"id"`
+	Message  string `json:"message"`
+}
+
+func main() {
+	var env envConfig
+	if err := envconfig.Process("", &env); err != nil {
+		log.Printf("[ERROR] Failed to process env var: %s", err)
+		os.Exit(1)
+	}
+
+	t, err := cepubsub.New(context.Background(),
+		cepubsub.WithProjectID(env.ProjectID))
+	if err != nil {
+		log.Printf("failed to create pubsub transport, %s", err.Error())
+		os.Exit(1)
+	}
+	c, err := cloudevents.NewClient(t, cloudevents.WithTimeNow(), cloudevents.WithUUIDs())
+	if err != nil {
+		log.Printf("failed to create client, %s", err.Error())
+		os.Exit(1)
+	}
+
+	for i, topic := range strings.Split(env.TopicIDs, ",") {
+		ctx := cecontext.WithTopic(context.Background(), topic)
+		event := cloudevents.NewEvent(cloudevents.VersionV03)
+		event.SetType("com.cloudevents.sample.sent")
+		event.SetSource("github.com/cloudevents/sdk-go/cmd/samples/pubsub/multisender/")
+		_ = event.SetData(&Example{
+			Sequence: i,
+			Message:  "HELLO " + topic,
+		})
+
+		_, err = c.Send(ctx, event)
+
+		if err != nil {
+			log.Printf("failed to send: %v", err)
+			os.Exit(1)
+		}
+	}
+
+	os.Exit(0)
+}

cmd/samples/pubsub/receiver/main.go

@@ -8,10 +8,28 @@ import (
 
 	"github.com/cloudevents/sdk-go"
 	"github.com/cloudevents/sdk-go/pkg/cloudevents/client"
-	cloudeventspubsub "github.com/cloudevents/sdk-go/pkg/cloudevents/transport/pubsub"
+	cepubsub "github.com/cloudevents/sdk-go/pkg/cloudevents/transport/pubsub"
+	pscontext "github.com/cloudevents/sdk-go/pkg/cloudevents/transport/pubsub/context"
 	"github.com/kelseyhightower/envconfig"
 )
 
+/*
+
+To setup:
+
+gcloud pubsub topics create demo_cloudevents
+gcloud pubsub subscriptions create foo --topic=demo_cloudevents
+
+To test:
+
+gcloud pubsub topics publish demo_cloudevents --message='{"Hello": "world"}'
+
+To fix a bad message:
+
+gcloud pubsub subscriptions pull --auto-ack foo
+
+*/
+
 type envConfig struct {
 	ProjectID string `envconfig:"GOOGLE_CLOUD_PROJECT"`
 
@@ -28,7 +46,7 @@ type Example struct {
 func receive(ctx context.Context, event cloudevents.Event, resp *cloudevents.EventResponse) error {
 	fmt.Printf("Event Context: %+v\n", event.Context)
 
-	fmt.Printf("Transport Context: %+v\n", cloudeventspubsub.TransportContextFrom(ctx))
+	fmt.Printf("Transport Context: %+v\n", pscontext.TransportContextFrom(ctx))
 
 	data := &Example{}
 	if err := event.DataAs(data); err != nil {
@@ -49,10 +67,10 @@ func main() {
 		os.Exit(1)
 	}
 
-	t, err := cloudeventspubsub.New(context.Background(),
-		cloudeventspubsub.WithProjectID(env.ProjectID),
-		cloudeventspubsub.WithTopicID(env.TopicID),
-		cloudeventspubsub.WithSubscriptionID(env.SubscriptionID))
+	t, err := cepubsub.New(context.Background(),
+		cepubsub.WithProjectID(env.ProjectID),
+		cepubsub.WithTopicID(env.TopicID),
+		cepubsub.WithSubscriptionID(env.SubscriptionID))
 	if err != nil {
 		log.Fatalf("failed to create pubsub transport, %s", err.Error())
 	}
@@ -64,6 +82,6 @@ func main() {
 	log.Println("Created client, listening...")
 
 	if err := c.StartReceiver(ctx, receive); err != nil {
-		log.Fatalf("failed to start nats receiver, %s", err.Error())
+		log.Fatalf("failed to start pubsub receiver, %s", err.Error())
 	}
 }

cmd/samples/pubsub/sender/main.go

@@ -6,7 +6,7 @@ import (
 	"os"
 
 	"github.com/cloudevents/sdk-go"
-	cloudeventspubsub "github.com/cloudevents/sdk-go/pkg/cloudevents/transport/pubsub"
+	cepubsub "github.com/cloudevents/sdk-go/pkg/cloudevents/transport/pubsub"
 	"github.com/kelseyhightower/envconfig"
 )
 
@@ -29,9 +29,9 @@ func main() {
 		os.Exit(1)
 	}
 
-	t, err := cloudeventspubsub.New(context.Background(),
-		cloudeventspubsub.WithProjectID(env.ProjectID),
-		cloudeventspubsub.WithTopicID(env.TopicID))
+	t, err := cepubsub.New(context.Background(),
+		cepubsub.WithProjectID(env.ProjectID),
+		cepubsub.WithTopicID(env.TopicID))
 	if err != nil {
 		log.Printf("failed to create pubsub transport, %s", err.Error())
 		os.Exit(1)

pkg/cloudevents/context/context.go

@@ -30,6 +30,28 @@ func TargetFrom(ctx context.Context) *url.URL {
 	return nil
 }
 
+// Opaque key type used to store topic
+type topicKeyType struct{}
+
+var topicKey = topicKeyType{}
+
+// WithTopic returns back a new context with the given topic. Topic is intended to be transport dependent.
+// For pubsub transport, `topic` should be a Pub/Sub Topic ID.
+func WithTopic(ctx context.Context, topic string) context.Context {
+	return context.WithValue(ctx, topicKey, topic)
+}
+
+// TopicFrom looks in the given context and returns `topic` as a string if found and valid, otherwise "".
+func TopicFrom(ctx context.Context) string {
+	c := ctx.Value(topicKey)
+	if c != nil {
+		if s, ok := c.(string); ok {
+			return s
+		}
+	}
+	return ""
+}
+
 // Opaque key type used to store encoding
 type encodingKeyType struct{}
 

pkg/cloudevents/transport/pubsub/context.go → pkg/cloudevents/transport/pubsub/context/context.go

@@ -1,4 +1,4 @@
-package pubsub
+package context
 
 import (
 	"context"

pkg/cloudevents/transport/pubsub/context/context_test.go

@@ -0,0 +1 @@
+package context_test