AWS Lambda Cheatsheet¶

Estimated time to read: 8 minutes

Overview¶

AWS Lambda is a serverless compute service that lets you run your code without provisioning or managing servers. Lambda automatically scales and manages your applications, so you can build applications that automatically respond to changes in demand.

Key Concepts¶

Serverless Functions: Lambda functions are the atomic core of the service. They consist of discrete blocks of code written in supported runtimes (e.g., Python, Node.js) and are invoked in direct response to system events.

Event Trigger Architecture: Triggers are the specific events that initiate function execution. High-impact examples include API Gateway requests, S3 bucket mutations, and CloudWatch scheduled events.

Strategic Lambda Layers: Layers are a distribution mechanism for shared code and dependencies. Utilise them to manage common libraries across multiple functions, reducing deployment package size and build complexity.

Optimised Environment Runtimes: Language-specific environments that execute your functions. Current high-performance versions include Python 3.13, Node.js 22, Java 21, and .NET 8.

Cold Start Latency Mitigation: The latency penalty incurred when a new execution container is provisioned. For high-priority Java workloads, enable Lambda SnapStart to achieve near-instantaneous startup times.

Architectural Processor Efficiency: Configure functions to use ARM-based Graviton3 processors to achieve superior cost-performance efficiency compared to legacy x86 architectures.

Lambda Function Components¶

Logical Execution Handler: The primary entry point for function execution. The handler is responsible for processing the event payload and returning a structured response to the invoker.

Immutable Event Object: Contains the complete metadata related to the triggering event, allowing the function to react dynamically to external system changes.

Runtime Context Object: Provides real-time information about the execution environment, including available memory, remaining execution time, and AWS request identification.

Getting Started¶

• Create a Lambda function using the AWS Management Console, AWS CLI, or an SDK.
• Add a trigger to automatically invoke the function or invoke it manually using the AWS CLI, SDK, or Lambda console.
• Monitor function execution with Amazon CloudWatch Logs.

Getting started example Commands¶

Create a Lambda function:

    aws lambda create-function --function-name <function_name> --runtime <runtime> --role <role_arn> --handler <handler> --zip-file fileb://<code_zip>

   aws lambda update-function-code --function-name <function_name> --zip-file fileb://<code_zip>

Invoke a Lambda function:

   aws lambda invoke --function-name <function_name> --payload <input_json> <output_file>

Add a trigger to a Lambda function:

   aws lambda create-event-source-mapping --function-name <function_name> --event-source-arn <event_source_arn>

List Lambda functions:

   aws lambda list-functions

Delete a Lambda function:

   aws lambda delete-function --function-name <function_name>

IAM Permissions and Least Privilege: High-security architectures require that Lambda functions have only the minimum necessary permissions. Attach granular IAM policies to the execution role to control interactions with other AWS services.

Observability and Monitoring: Lambda integrates natively with Amazon CloudWatch. Utilise CloudWatch Logs for deep execution traces and CloudWatch Metrics to monitor concurrency, error rates, and duration.

Consumption-Based Pricing: Pricing is strictly calculated based on the number of requests and the precise duration of execution. This shared-responsibility model ensures you only pay for the compute cycles actually consumed.

Here's a table with 30 useful AWS Lambda commands for engineers:

These commands can be used with the AWS Command Line Interface (CLI) to manage and interact with your AWS Lambda functions, layers, and related resources. Remember to replace the necessary placeholders (like <function_name> or <runtime>) with your own values when using the commands.

These additional commands extend your ability to manage various aspects of AWS Lambda, such as function configurations, provisioned concurrency, event invoke configurations, and code signing configurations. As before, replace the necessary placeholders with your own values when using the commands.

These commands will help you manage concurrency configurations and policies related to event sources, filter Lambda functions by the runtime or layer version, and manage dead-letter queue configurations.

Keep in mind¶

AWS is continuously evolving, and new features or commands may be added. It's always a good idea to consult the official AWS CLI documentation for the most up-to-date information on available commands: https://docs.aws.amazon.com/cli/latest/reference/lambda/index.html