AWS Lambda

Deep Dive

Documentation

Hi there, I’m Sanjay 👋!

About me

• 🔭 Working: Lead Software Engineer - working on Spring Boot, Reactive Programming, Microservices, Kafka, Cassandra, Kubernetes, AWS.
• 🖥️ Interests: I love building cool Software & Systems, Self-Hosting, Gaming
• 🌱 Learning: Go | Rust | Scala | Design Patterns
• 💬 Ask me about: Java | Reactive Spring | Containers | AWS
• 🧑‍🤝‍🧑 Collaboration: Looking to collaborate on several projects over here, check out my GitHub

Languages, Frameworks and Platforms

What is AWS Lambda Function

• A Compute Service to run code without Provisioning or Managing Servers
• Uses Containerization tech called Firecracker
• Handles Server & OS Maintenance, Provisioning, Auto-Scaling, Logging
• Code in one of the Languages supported by Lambda Runtimes

Lambda Concepts

• Function: a resource invoked to run your code
• Trigger: a resource/config that invokes a Lambda Function
• Event: a JSON-formatted data for a Lambda Function to Process
• Event Source Mapping: a resource that reads items from a Stream/Queue & invokes a function
• Execution Env: provides a secure and isolated Runtime Environment for your Lambda function
• Runtime: provides a lang-specific Environment that runs in an Execution Environment

What is Lambda Runtimes

• Runtime provides a lang-specific env that runs in an execution env
• It relays invocation Events, Context, & Responses between Lambda & the Function
• Use AWS provided Lambda Runtimes or Build your own by implementing Runtime API

Execution Environment & Runtime

Supported Lambda Runtimes

Micronaut Custom Runtime Implementation Example

Lambda Function Java

public class MsgHandler implements RequestHandler<String, String> {
    public String handleRequest(String input, Context ctx) {
        context.getLogger().log("Input: " + input);
        return "Hello World - " + input;
    }
}

public class StreamHandler implements RequestStreamHandler {
    public void handleRequest(InputStream is, OutputStream os, Context ctx) {
        String input = IOUtils.toString(is, "UTF-8");
        os.write(("Hello World - " + input).getBytes());
    }
}

public class NoInterfaceHandler {
    public String customHandle(String input, Context context) {
        context.getLogger().log("Input: " + input);
        return "Hello World - " + input;
    }
}

Features

• Automatically manages the underlying Compute Resources
• Concurrency and Scaling controls
• Pay Per Request Execution is millis
• Multiple Event Sources: API-GW, SQS, S3, DynamoDB, etc.
• Functions defined as Container Images
• Lambda Extensions
• Execute inside Private Subnets inside a VPC
• File Systems Access + EFS

Limitations

• Memory: 128 MB to 10,240 MB
• No Direct Way to assign CPU: 1,769 MB memory is equivalent of one vCPU
• Function Timeouts: 15 minutes
• Invocation Payload: 6 MB (sync) & 256 KB (async)
• File descriptors: 1024
• Execution processes/threads: 1024
• No Async Processing Allowed: Lambda Instance Freezes once invocation is completed
• 1 Lambda Instance serves only 1 request at time

Other Compute Options

Questions?