CloudEvents event parsing for gcp (https://cloudevents.github.io/sdk-go/)

main.go

package main

import (
	"context"
	"encoding/base64"
	"encoding/json"
	"fmt"

	cloudevents "github.com/cloudevents/sdk-go/v2"

	logging "google.golang.org/api/logging/v2"
	pubsub "google.golang.org/api/pubsub/v1"

	// https://godoc.org/google.golang.org/api/servicecontrol/v1#AuditLog
	svc "google.golang.org/api/servicecontrol/v1"
)

const (
	pubSubEventType   = "com.google.cloud.pubsub.topic.publish"
	auditLogEventType = "com.google.cloud.auditlog.event"
)

type wrappedPubSub struct {
	Subscription string               `json:"subscription"`
	Message      pubsub.PubsubMessage `json:"message"`
}

func Receive(ctx context.Context, event cloudevents.Event) error {
	fmt.Printf("EventID:   >> : %s\n", event.ID())

	switch event.Type() {

	case pubSubEventType:
		pubsubData := &wrappedPubSub{}
		if err := event.DataAs(pubsubData); err != nil {
			return fmt.Errorf("Got Data Error: %s\n", err)
		}
		decoded, err := base64.StdEncoding.DecodeString(pubsubData.Message.Data)
		if err != nil {
			return fmt.Errorf("Unable  to decode pubsub message: %v\n", err)
		}
		fmt.Printf("Pubsub Message %s\n", decoded)

	case auditLogEventType:

		loggingData := &logging.LogEntry{}
		if err := event.DataAs(loggingData); err != nil {
			fmt.Printf("DataAs Error %v", err)
			return fmt.Errorf("Got Data Error %v", err)
		}
		audit := &svc.AuditLog{}

		err := json.Unmarshal(loggingData.ProtoPayload, audit)
		if err != nil {
			return fmt.Errorf("Got Data Error %v", err)
		}
		fmt.Printf("ResourceName: %v\n", audit.ResourceName)

	default:

		return fmt.Errorf("Unknown Event type")
	}
	return nil
}

func main() {

	c, err := cloudevents.NewDefaultClient()
	if err != nil {
		fmt.Printf("failed to create client, %v", err)
	}

	err = c.StartReceiver(context.Background(), Receive)
	if err != nil {
		fmt.Printf("failed to StartReceiver, %v", err)
	}
}