AWS Lambda Cheatsheet¶

Estimated time to read: 7 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¶

Functions Lambda functions are the core unit of Lambda. They are blocks of code written in a supported runtime and are invoked in response to an event.

Triggers Events that cause Lambda functions to start executing. Examples of triggers are API Gateway, S3, and CloudWatch Events.

Layers Lambda layers are a distribution mechanism for function code and dependencies. You can use them to manage and share common code across multiple functions.

Runtime A language-specific environment that runs your Lambda function. AWS provides runtimes for several programming languages, including Python, go, Node.js, Java, and more.

Cold Start The initial execution of a Lambda function when a new container is created to handle the request. This typically results in higher latency.

Lambda Function Components¶

Handler The entry point of your Lambda function. The handler processes the event and returns a response.

Event Object Contains information about the trigger event that initiated the Lambda function.

Context Object Contains information about the runtime and function execution environment.

Getting Started¶

1. Create a Lambda function using the AWS Management Console, AWS CLI, or an SDK.
2. Add a trigger to automatically invoke the function or invoke it manually using the AWS CLI, SDK, or Lambda console.
3. 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: Ensure your Lambda function has the necessary permissions by attaching IAM policies to the function's execution role. This allows your function to interact with other AWS services.

Monitoring and Logging: Lambda automatically integrates with Amazon CloudWatch for logging and monitoring. Check the CloudWatch Logs for your function's execution logs and CloudWatch Metrics for monitoring performance and errors.

Pricing: AWS Lambda pricing is based on the number of requests and the duration of function execution. You only pay for the compute time that you actually use. There is a generous free tier available.

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