dead_letter_tests

README

Dead Letter Topic

These functions test the Pub/Sub retries and dead-letter topics.

Test Cloud Functions

First deploy the pub-sub-triggered and HTTP function using --gen2, it uses cloud run to deploy functions. The configure the topics and subscriptions. Enable "Push authentication" with audience URL as your cloud-run URL. Also make sure to provide the "Cloud Run Invoker" and "Cloud Function Invoker" permission to cloud-run service account.

In this example, the cloud functions AckPubMessage and BadAckFunc tests the subscription retries and dead-letter topics. Main Pub/Sub topic radio-pluto, has cloud http trigger func BadAckFunc is attached to it. This always returns code 500. Since radio-pluto topic is set to retry 5 times, the message will be sent 5 times to BadAckFunc. Once all retries fails, the message will be pushed to pluto-dead-letter topic.

Dead letter topic: pluto-dead-letter has listener AckPubMessage. Once the messages is received this function consumes it. Once consumed message is discarded (if configured).

# Activate  right project configuration
gcloud config configurations activate gcp-experiments
# Note that --runtime go122  is supported 
# https://cloud.google.com/functions/docs/runtime-support#go
# Ensure that the Cloud functions has permission "Cloud Run Invoker" and "Cloud Function Invoker"
gcloud functions deploy AckPubMessage  --gen2 --runtime go122 --trigger-topic pluto-dead-letter --project=gcp-experiments-334602
# Deploy a http func so we can return a error code (to test retry and dead-letter)
gcloud functions deploy BadAckFunc  --gen2 --runtime go122 --trigger-http --project=gcp-experiments-334602

Testing Message Retries

Pushing messages using command:

# Push a message to a 'radio-pluto' topic
gcloud pubsub topics publish radio-pluto --message='{"name": "GCP", "rating": "12-star"}' --project=gcp-experiments-334602

Then observe the logs for retries.

Multiple Subscriptions on a topic.

This is not tested yet.

Documentation

Index

• type MessagePublishedData
• type PubSubMessage

Types

type MessagePublishedData

type MessagePublishedData struct {
	Message      PubSubMessage `json:"message,omitempty"`
	Subscription string        `json:"subscription,omitempty"`
}

MessagePublishedData contains the full Pub/Sub message See the pubsub-documentation for more details:

type PubSubMessage

type PubSubMessage struct {
	Data       []byte            `json:"data,omitempty"`
	ID         string            `json:"id"`
	Attributes map[string]string `json:"attributes,omitempty"`
}

PubSubMessage is the payload of a Pub/Sub event. See the event-documentation for more details: