rust-demo

rust graceful shutdown demo

This folder contains a simple rust function with CloudWatch Lambda Insight enabled. CloudWatch Lambda Insight is monitoring and troubleshooting solution for serverless application. Its agent is an external extension. Any external extension will work. We use Lambda Insight extension simply because it is readily available.

It is recommended to use the latest Lambda Insights extension

  Layers:
    # https://docs.aws.amazon.com/AmazonCloudWatch/latest/monitoring/Lambda-Insights-extension-versions.html
    - !Sub "arn:aws:lambda:${AWS::Region}:580247275435:layer:LambdaInsightsExtension-Arm64:5" # Add Lambda Insight Extension
  Policies:
    # Add IAM Permission for Lambda Insight Extension
    - CloudWatchLambdaInsightsExecutionRolePolicy

In the function, a simple signal handler is added. It will be executed when the lambda runtime receives a SIGTERM、SIGINT signal. You can also add more signal types yourself.

// Handle SIGTERM signal:
// https://tokio.rs/tokio/topics/shutdown
// https://rust-cli.github.io/book/in-depth/signals.html
tokio::spawn(async move {
    let mut sigint = signal(SignalKind::interrupt()).unwrap();
    let mut sigterm = signal(SignalKind::terminate()).unwrap();
    tokio::select! {
        _sigint = sigint.recv() => {
            println!("[runtime] SIGINT received");
            println!("[runtime] Graceful shutdown in progress ...");
            println!("[runtime] Graceful shutdown completed");
            std::process::exit(0);
        },
        _sigterm = sigterm.recv()=> {
            println!("[runtime] SIGTERM received");
            println!("[runtime] Graceful shutdown in progress ...");
            println!("[runtime] Graceful shutdown completed");
            std::process::exit(0);
        },
    }
});

Use the following AWS SAM CLI commands to build and deploy this demo.

# https://docs.aws.amazon.com/serverless-application-model/latest/developerguide/building-rust.html#building-rust-prerequisites
sam build --beta-features
sam deploy

Take note of the output value of RustHelloWorldApi. Use curl to invoke the api and trigger the lambda function at least once.

curl "replace this with value of RustHelloWorldApi"

Waite for several minutes, check the function's log messages in CloudWatch. If you see a log line containing "SIGTERM received", it works!

for example:

2023-12-15T13:28:12.634+08:00	INIT_START Runtime Version: provided:al2023.v10 Runtime Version ARN: arn:aws:lambda:us-east-1::runtime:389fcaae1b213b40d38ed791dfb615af1a71a32d6996ff7c4afdde3d5af4b6f2
2023-12-15T13:28:12.690+08:00	LOGS Name: cloudwatch_lambda_agent State: Subscribed Types: [Platform]
2023-12-15T13:28:12.715+08:00	EXTENSION Name: cloudwatch_lambda_agent State: Ready Events: [INVOKE, SHUTDOWN]
2023-12-15T13:28:12.717+08:00	START RequestId: ca7dfb1a-9b58-4a07-ba4d-feeea6d61f80 Version: $LATEST
2023-12-15T13:28:12.850+08:00	END RequestId: ca7dfb1a-9b58-4a07-ba4d-feeea6d61f80
2023-12-15T13:28:12.850+08:00	REPORT RequestId: ca7dfb1a-9b58-4a07-ba4d-feeea6d61f80 Duration: 133.17 ms Billed Duration: 215 ms Memory Size: 128 MB Max Memory Used: 26 MB Init Duration: 81.74 ms
2023-12-15T13:28:46.863+08:00	START RequestId: 7e16e208-7b23-44ec-8ce0-793210971ed6 Version: $LATEST
2023-12-15T13:28:46.869+08:00	END RequestId: 7e16e208-7b23-44ec-8ce0-793210971ed6
2023-12-15T13:28:46.869+08:00	REPORT RequestId: 7e16e208-7b23-44ec-8ce0-793210971ed6 Duration: 6.54 ms Billed Duration: 7 ms Memory Size: 128 MB Max Memory Used: 26 MB
2023-12-15T13:34:54.526+08:00	[runtime] SIGTERM received
2023-12-15T13:34:54.526+08:00	[runtime] Graceful shutdown in progress ...
2023-12-15T13:34:54.526+08:00	[runtime] Graceful shutdown completed 

Tested Runtimes

language version	Identifier	Operating system	Architectures	Support status
rust	provided.al2023	Amazon Linux 2023	arm64 x86_64	✅Support
rust	provided.al2	Amazon Linux 2	arm64 x86_64	✅Support

Note: The Rust runtime client is an experimental package. It is subject to change and intended only for evaluation purposes.

Note: Make sure your SAM CLI version is the latest version,SAM CLI version 1.103.0 or newer is recommended.

Reference:

• Building Lambda functions with Rust
• AWS SAM Documentation
  • Building Rust Lambda functions with Cargo Lambda
• cargo-lambda