I am trying to set up a toy to understand Google's Pub/Sub service Go
client API. I have had no trouble with publishing and have a local
emulator for the Google Scheduler service to build against, but I am
having a lot of trouble getting subscriptions to work.
I am able get a subscription to work with messages received if I first
create the topic using the Python example code.
This is the python from[1]:
```
from google.cloud import pubsub_v1
publisher = pubsub_v1.PublisherClient()
subscriber = pubsub_v1.SubscriberClient()
topic_path = publisher.topic_path(project, topic)
subscription_path = subscriber.subscription_path(project, subID)
# Wrap the subscriber in a 'with' block to automatically call close()
to
# close the underlying gRPC channel when done.
with subscriber:
subscription = subscriber.create_subscription(
request={"name": subscription_path, "topic": topic_path}
)
```
However, when I do what I understand to be the equivalent Go code, I am
unable to receive any messages.
This is what I take to be the equivalent Go code.
```
client, err := pubsub.NewClient(ctx, project)
if err != nil {
log.Fatalf("failed to create pubsub client: %v", err)
}
t, err := client.CreateTopic(ctx, topic)
if err != nil {
log.Fatalf("failed to create topic %q: %v", topic, err)
}
s, err := client.CreateSubscription(ctx, subID,
pubsub.SubscriptionConfig{Topic: t})
if err != nil {
log.Fatalf("failed to create subscription %q %q: %v", topic,
subID, err)
}
```
In both cases the message receiver code is as follows, though in the
case where python sets up the topic, this is prefaced with `s :=
client.Subscription(subID)` in place of the Go code above.
```
err = s.Receive(ctx, func(ctx context.Context, m *pubsub.Message) {
log.Printf("received: %#v", m)
m.Ack()
})
```
The complete code of the working toy (requiring python to set it up) is
here [2] and the non-working version is here [3].
thanks
Dan
[1]
https://github.com/googleapis/python-pubsub/blob/b8352f91c63e0cb7d64c4d0e557651248cd301b5/samples/snippets/subscriber.py#L66-L89
[2]https://play.golang.org/p/0kXLN8H-rCG
[3]https://play.golang.org/p/Fva4BYrtDXE
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