Invoke a Lambda function from an Amazon SNS trigger
The following code examples show how to implement a Lambda function that receives an event triggered by receiving messages from an SNS topic. The function retrieves the messages from the event parameter and logs the content of each message.
- .NET
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- Amazon 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. Consuming an SNS event with Lambda using .NET.
// Copyright Amazon.com, Inc. or its affiliates. All Rights Reserved. // SPDX-License-Identifier: Apache-2.0 using Amazon.Lambda.Core; using Amazon.Lambda.SNSEvents; // 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 SnsIntegration; public class Function { public async Task FunctionHandler(SNSEvent evnt, ILambdaContext context) { foreach (var record in evnt.Records) { await ProcessRecordAsync(record, context); } context.Logger.LogInformation("done"); } private async Task ProcessRecordAsync(SNSEvent.SNSRecord record, ILambdaContext context) { try { context.Logger.LogInformation($"Processed record {record.Sns.Message}"); // TODO: Do interesting work based on the new message await Task.CompletedTask; } catch (Exception e) { //You can use Dead Letter Queue to handle failures. By configuring a Lambda DLQ. context.Logger.LogError($"An error occurred"); throw; } } }
- Go
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- SDK for Go V2
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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. Consuming an SNS event with Lambda using Go.
// Copyright Amazon.com, Inc. or its affiliates. All Rights Reserved. // SPDX-License-Identifier: Apache-2.0 package main import ( "context" "fmt" "github.com/aws/aws-lambda-go/events" "github.com/aws/aws-lambda-go/lambda" ) func handler(ctx context.Context, snsEvent events.SNSEvent) { for _, record := range snsEvent.Records { processMessage(record) } fmt.Println("done") } func processMessage(record events.SNSEventRecord) { message := record.SNS.Message fmt.Printf("Processed message: %s\n", message) // TODO: Process your record here } func main() { lambda.Start(handler) }
- Java
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- SDK for Java 2.x
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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. Consuming an SNS event with Lambda using Java.
// Copyright Amazon.com, Inc. or its affiliates. All Rights Reserved. // SPDX-License-Identifier: Apache-2.0 package example; import com.amazonaws.services.lambda.runtime.Context; import com.amazonaws.services.lambda.runtime.LambdaLogger; import com.amazonaws.services.lambda.runtime.RequestHandler; import com.amazonaws.services.lambda.runtime.events.SNSEvent; import com.amazonaws.services.lambda.runtime.events.SNSEvent.SNSRecord; import java.util.Iterator; import java.util.List; public class SNSEventHandler implements RequestHandler<SNSEvent, Boolean> { LambdaLogger logger; @Override public Boolean handleRequest(SNSEvent event, Context context) { logger = context.getLogger(); List<SNSRecord> records = event.getRecords(); if (!records.isEmpty()) { Iterator<SNSRecord> recordsIter = records.iterator(); while (recordsIter.hasNext()) { processRecord(recordsIter.next()); } } return Boolean.TRUE; } public void processRecord(SNSRecord record) { try { String message = record.getSNS().getMessage(); logger.log("message: " + message); } catch (Exception e) { throw new RuntimeException(e); } } }
- JavaScript
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- SDK for JavaScript (v3)
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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. Consuming an SNS event with Lambda using JavaScript.
// Copyright Amazon.com, Inc. or its affiliates. All Rights Reserved. // SPDX-License-Identifier: Apache-2.0 exports.handler = async (event, context) => { for (const record of event.Records) { await processMessageAsync(record); } console.info("done"); }; async function processMessageAsync(record) { try { const message = JSON.stringify(record.Sns.Message); console.log(`Processed message ${message}`); await Promise.resolve(1); //Placeholder for actual async work } catch (err) { console.error("An error occurred"); throw err; } }
Consuming an SNS event with Lambda using TypeScript.
// Copyright Amazon.com, Inc. or its affiliates. All Rights Reserved. // SPDX-License-Identifier: Apache-2.0 import { SNSEvent, Context, SNSHandler, SNSEventRecord } from "aws-lambda"; export const functionHandler: SNSHandler = async ( event: SNSEvent, context: Context ): Promise<void> => { for (const record of event.Records) { await processMessageAsync(record); } console.info("done"); }; async function processMessageAsync(record: SNSEventRecord): Promise<any> { try { const message: string = JSON.stringify(record.Sns.Message); console.log(`Processed message ${message}`); await Promise.resolve(1); //Placeholder for actual async work } catch (err) { console.error("An error occurred"); throw err; } }
- PHP
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- SDK for PHP
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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. Consuming an SNS event with Lambda using PHP.
// Copyright Amazon.com, Inc. or its affiliates. All Rights Reserved. // SPDX-License-Identifier: Apache-2.0 <?php /* Since native PHP support for AWS Lambda is not available, we are utilizing Bref's PHP functions runtime for AWS Lambda. For more information on Bref's PHP runtime for Lambda, refer to: https://bref.sh/docs/runtimes/function Another approach would be to create a custom runtime. A practical example can be found here: https://aws.amazon.com/blogs/apn/aws-lambda-custom-runtime-for-php-a-practical-example/ */ // Additional composer packages may be required when using Bref or any other PHP functions runtime. // require __DIR__ . '/vendor/autoload.php'; use Bref\Context\Context; use Bref\Event\Sns\SnsEvent; use Bref\Event\Sns\SnsHandler; class Handler extends SnsHandler { public function handleSns(SnsEvent $event, Context $context): void { foreach ($event->getRecords() as $record) { $message = $record->getMessage(); // TODO: Implement your custom processing logic here // Any exception thrown will be logged and the invocation will be marked as failed echo "Processed Message: $message" . PHP_EOL; } } } return new Handler();
- Python
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- SDK for Python (Boto3)
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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. Consuming an SNS event with Lambda using Python.
# Copyright Amazon.com, Inc. or its affiliates. All Rights Reserved. # SPDX-License-Identifier: Apache-2.0 def lambda_handler(event, context): for record in event['Records']: process_message(record) print("done") def process_message(record): try: message = record['Sns']['Message'] print(f"Processed message {message}") # TODO; Process your record here except Exception as e: print("An error occurred") raise e
- Ruby
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- SDK for Ruby
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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. Consuming an SNS event with Lambda using Ruby.
# Copyright Amazon.com, Inc. or its affiliates. All Rights Reserved. # SPDX-License-Identifier: Apache-2.0 def lambda_handler(event:, context:) event['Records'].map { |record| process_message(record) } end def process_message(record) message = record['Sns']['Message'] puts("Processing message: #{message}") rescue StandardError => e puts("Error processing message: #{e}") raise end
- Rust
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- SDK for Rust
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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. Consuming an SNS event with Lambda using Rust.
// Copyright Amazon.com, Inc. or its affiliates. All Rights Reserved. // SPDX-License-Identifier: Apache-2.0 use aws_lambda_events::event::sns::SnsEvent; use aws_lambda_events::sns::SnsRecord; use lambda_runtime::{run, service_fn, Error, LambdaEvent}; use tracing::info; // Built with the following dependencies: // aws_lambda_events = { version = "0.10.0", default-features = false, features = ["sns"] } // lambda_runtime = "0.8.1" // tokio = { version = "1", features = ["macros"] } // tracing = { version = "0.1", features = ["log"] } // tracing-subscriber = { version = "0.3", default-features = false, features = ["fmt"] } async fn function_handler(event: LambdaEvent<SnsEvent>) -> Result<(), Error> { for event in event.payload.records { process_record(&event)?; } Ok(()) } fn process_record(record: &SnsRecord) -> Result<(), Error> { info!("Processing SNS Message: {}", record.sns.message); // Implement your record handling code here. Ok(()) } #[tokio::main] async fn main() -> Result<(), Error> { tracing_subscriber::fmt() .with_max_level(tracing::Level::INFO) .with_target(false) .without_time() .init(); run(service_fn(function_handler)).await }
For a complete list of Amazon SDK developer guides and code examples, see Using Amazon SNS with an Amazon SDK. This topic also includes information about getting started and details about previous SDK versions.