Using Google Cloud Functions to integrate AWS SNS and Google Cloud Pub/Sub using Go.
The SNS service makes a POST request to the Cloud Function URL when a new message is published to the SNS Topic. This function will validate the sender.
This function then publishes the message to Cloud Pub/Sub.
For this to work is expected that you are already familiar with setting up an AWS SNS topic.
Creating the topic that will receive SNS messages:
gcloud pubsub topics create sns-events
Creating a subscription to test the integration
gcloud pubsub subscriptions create sns-watcher --topic sns-events
Deploying the function. Replace [YOUR_STAGE_BUCKET] with your Cloud Functions staging bucket as well as SNS_ARN:
gcloud functions deploy PublishSNSMessage --set-env-vars TOPIC_NAME=sns-events,SNS_ARN=arn:aws:sns:AWS_REGION:AWS_ACCOUNT:my-sns-topic --runtime go111 --trigger-http --stage-bucket [YOUR_STAGE_BUCKET]
Once the function is deployed copy the httpsTrigger URL in the output.
Do not forget to add proper permissions to Service account in PubSub Topic.
In the AWS console go to your SNS topic and create a subscription. Choose HTTPS as the protocol and enter the Cloud Function URL you copied above and Create the subscription.
The subscription will be created in pending state. SNS then sends a confirmation request to the Cloud Function. The function recognises the request as a confirmation request and confirm it by fetching the URL provided by SNS.
Using the Publish feature in the SNS section of the AWS console to generate a test message in raw format. Wait a few seconds and then run the following command to confirm that Cloud Function relayed the message to Pub/Sub:
gcloud pubsub subscriptions pull sns-watcher --auto-ack