Timeout when publishing from AWS Lambda to SNS

Question

I'm trying to publish some data to SNS from a Lambda function call, but it doesn't seem to be working. My function code is -

public class Handler implements RequestHandler<DynamodbEvent, Void> {

    private static final String SNS_TOPIC_ARN = "arn:aws:sns:us-west-2:account_number:function_name";

    @Override
    public Void handleRequest(DynamodbEvent dynamodbEvent, Context context) {

        LambdaLogger logger = context.getLogger();

        AmazonSNSClient snsClient = new AmazonSNSClient(new DefaultAWSCredentialsProviderChain());
        snsClient.setRegion(Region.getRegion(Regions.US_WEST_2));

        for (DynamodbStreamRecord record : dynamodbEvent.getRecords()) {
            Map<String, AttributeValue> newImage = record.getDynamodb().getNewImage();

            if (newImage == null) {
                continue;
            }

            String sensorId = newImage.get("sensorID").getS();
            long timestamp = Long.parseLong(newImage.get("timestamp").getS());
            double temperature = Double.parseDouble(newImage.get("payload").getM().get("temp").getN());

            String data = sensorId + " " + timestamp + " " + temperature;

            logger.log(data);

            PublishRequest publishRequest = new PublishRequest(SNS_TOPIC_ARN, data);

            PublishResult publishResult = snsClient.publish(publishRequest);

            logger.log("Publish Successful " + publishResult.getMessageId());
        }

        snsClient.shutdown();

        return null;
    }
}

This call results in a timeout (10 seconds) and the lambda invocation fails. If I comment out the SNS publishing part, i.e., if I just log the data received from DynamoDB, it works just fine. As soon as the SNS publishing code is added, it times out.

The timeout message logged in CloudWatch is -

START RequestId: 8db74187-459b-42c5-8a06-b3a74873b236 Version: $LATEST END RequestId: 8db74187-459b-42c5-8a06-b3a74873b236 REPORT RequestId: 8db74187-459b-42c5-8a06-b3a74873b236 Duration: 10001.66 ms Billed Duration: 10000 ms Memory Size: 128 MB Max Memory Used: 37 MB Task timed out after 10.00 seconds

I have all the proper permissions in place, and I'm able to publish to SNS using just the following code running on my PC -

PublishRequest publishRequest = new PublishRequest(SNS_TOPIC_ARN, data);
PublishResult publishResult = snsClient.publish(publishRequest);
System.out.println("Publish Successful " + publishResult.getMessageId());

I have also tried using AmazonSNSAsyncClient instead of AmazonSNSClient, it gives the same result.

What am I missing here ?

Answer 1

Well, since none of the people who commented on my question are answering, I'll answer it myself.

Increasing the memory usage to 256 MB and timeout to 30 seconds seems to have solved the issue.

Answer 2

Increase the amount of memory allocated for the Lambda operation.

Answer 3

Increasing the memory allocated to the lambda function worked for me as well (this setting is in the lambda console under basic settings).

This one was maddening for me - I was using the same JAR file for 2 different lambda functions with identical configurations, and the SNS call was working for one but timing out for the other. Maddening!