sdk-go/samples/pubsub/receiver/main.go

87 lines
2.1 KiB
Go

/*
Copyright 2021 The CloudEvents Authors
SPDX-License-Identifier: Apache-2.0
*/
package main
import (
"context"
"fmt"
"log"
"os"
cepubsub "github.com/cloudevents/sdk-go/protocol/pubsub/v2"
pscontext "github.com/cloudevents/sdk-go/protocol/pubsub/v2/context"
cloudevents "github.com/cloudevents/sdk-go/v2"
"github.com/cloudevents/sdk-go/v2/event"
"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" required:"true"`
TopicID string `envconfig:"PUBSUB_TOPIC" default:"demo_cloudevents" required:"true"`
SubscriptionID string `envconfig:"PUBSUB_SUBSCRIPTION" default:"foo" required:"true"`
}
type Example struct {
Sequence int `json:"id"`
Message string `json:"message"`
}
func receive(ctx context.Context, event event.Event) error {
fmt.Printf("Event Context: %+v\n", event.Context)
fmt.Printf("Protocol Context: %+v\n", pscontext.ProtocolContextFrom(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)
}
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 protocol, %s", err.Error())
}
c, err := cloudevents.NewClient(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())
}
}