Publish to Iot from Lambda

[Lacutas82]

I am really struggling to publish to AWS Iot from within a lambda using the AWS SDK. There is very little information available online, but from the methods and properties available within the package it appears it should be possible. When I deploy this lambda and run a test, all I get is a time out after 3 seconds (changing the lambda timeout does increase this time, but it still times out), and it appears the final Publish Response log message isn't executed. This leads me to believe that something is going wrong when calling PublishAsync, but I can't figure out what. Is anyone able to offer any insight?

I also have an IAM Iot Publish policy attached to the lambda.

I should also add, the catch isn't being executed so I don't believe an exception is being thrown.

        public async Task<PublishResponse> FunctionHandlerAsync(object input, ILambdaContext context)
        {
            try
            {
                var amazonIotDataConfig = new AmazonIotDataConfig
                {
                    RegionEndpoint = RegionEndpoint.USEast1,
                    UseHttp = false,
                    SignatureVersion = "4"
                };

                var serviceUrl = "https://**************-ats.iot.us-east-1.amazonaws.com";
                context.Logger.LogLine($"Service Url: {serviceUrl}");

                amazonIotDataConfig.ServiceURL = serviceUrl;

                context.Logger.LogLine($"Creating AmazonIotDataClient...");
                var amazonIotDataClient = new AmazonIotDataClient("********", "********", amazonIotDataConfig);

                var memoryStream = new MemoryStream(Encoding.UTF8.GetBytes("Hello World"));
                var publishRequest = new PublishRequest
                {
                    Qos = 1,
                    Payload = memoryStream,
                    Topic = "HelloWorld"
                };

                context.Logger.LogLine($"Publishing message to Iot...");
                var publishResponse = await amazonIotDataClient.PublishAsync(publishRequest);

                context.Logger.LogLine($"Publish Response: {JsonSerializer.Serialize(publishResponse)}");
                return publishResponse;
            } 
            catch (Exception ex)
            {
                context.Logger.LogLine($"Exception: {ex.Message}");
                throw ex;
            }
        }

[Lacutas82]

The below works from within a lambda and have messages being published

        public void FunctionHandler(object input, ILambdaContext context)
        {
            try
            {
                var amazonIotDataConfig = new AmazonIotDataConfig
                {
                    RegionEndpoint = RegionEndpoint.USEast1,
                    UseHttp = true,
                    SignatureVersion = "4"
                };

                var serviceUrl = "https://************-ats.iot.us-east-1.amazonaws.com";
                amazonIotDataConfig.ServiceURL = serviceUrl;

                context.Logger.LogLine("Creating AmazonIotDataClient...");
                var amazonIotDataClient = new AmazonIotDataClient(amazonIotDataConfig);

                var memoryStream = new MemoryStream(Encoding.UTF8.GetBytes(JsonSerializer.Serialize(new
                {
                    message = $"Hello World @ {DateTime.Now:O}"
                })));
                var publishRequest = new PublishRequest
                {
                    Qos = 0,
                    Payload = memoryStream,
                    Topic = "HelloWorld"
                };

                context.Logger.LogLine("Publishing to Topic...");
                var publishResponse = amazonIotDataClient.PublishAsync(publishRequest).Result;

                context.Logger.LogLine($"Publish Result: {publishResponse.HttpStatusCode}");
            }
            catch (Exception ex)
            {
                context.Logger.LogLine($"Exception: {ex.Message}");
            }
        }

[github-actions[bot]]

Hello! Reopening this discussion to make it searchable.