The following code examples show how to implement partial batch response for Lambda functions that receive events from a Kinesis stream. The function reports the batch item failures in the response, signaling to Lambda to retry those messages later.
- SDK for .NET
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Note
There's more on GitHub. Find the complete example and learn how to set up and run in the Serverless examples
repository. Reporting Kinesis batch item failures with Lambda using .NET.
// Copyright Amazon.com, Inc. or its affiliates. All Rights Reserved. // SPDX-License-Identifier: Apache-2.0 using System.Text; using System.Text.Json.Serialization; using Amazon.Lambda.Core; using Amazon.Lambda.KinesisEvents; using AWS.Lambda.Powertools.Logging; // Assembly attribute to enable the Lambda function's JSON input to be converted into a .NET class. [assembly: LambdaSerializer(typeof(Amazon.Lambda.Serialization.SystemTextJson.DefaultLambdaJsonSerializer))] namespace KinesisIntegration; public class Function { // Powertools Logger requires an environment variables against your function // POWERTOOLS_SERVICE_NAME [Logging(LogEvent = true)] public async Task<StreamsEventResponse> FunctionHandler(KinesisEvent evnt, ILambdaContext context) { if (evnt.Records.Count == 0) { Logger.LogInformation("Empty Kinesis Event received"); return new StreamsEventResponse(); } foreach (var record in evnt.Records) { try { Logger.LogInformation($"Processed Event with EventId: {record.EventId}"); string data = await GetRecordDataAsync(record.Kinesis, context); Logger.LogInformation($"Data: {data}"); // TODO: Do interesting work based on the new data } catch (Exception ex) { Logger.LogError($"An error occurred {ex.Message}"); /* Since we are working with streams, we can return the failed item immediately. Lambda will immediately begin to retry processing from this failed item onwards. */ return new StreamsEventResponse { BatchItemFailures = new List<StreamsEventResponse.BatchItemFailure> { new StreamsEventResponse.BatchItemFailure { ItemIdentifier = record.Kinesis.SequenceNumber } } }; } } Logger.LogInformation($"Successfully processed {evnt.Records.Count} records."); return new StreamsEventResponse(); } private async Task<string> GetRecordDataAsync(KinesisEvent.Record record, ILambdaContext context) { byte[] bytes = record.Data.ToArray(); string data = Encoding.UTF8.GetString(bytes); await Task.CompletedTask; //Placeholder for actual async work return data; } } public class StreamsEventResponse { [JsonPropertyName("batchItemFailures")] public IList<BatchItemFailure> BatchItemFailures { get; set; } public class BatchItemFailure { [JsonPropertyName("itemIdentifier")] public string ItemIdentifier { get; set; } } }
For a complete list of AWS SDK developer guides and code examples, see Using Lambda with an AWS SDK. This topic also includes information about getting started and details about previous SDK versions.