# Cheat Sheet #day19 - AWS Lambda Commands

### AWS Lambda Commands Cheat Sheet

AWS Lambda is a serverless compute service that lets you run code without provisioning or managing servers. Below is a cheat sheet of common AWS Lambda commands using the AWS CLI (Command Line Interface).

#### Setup

* **Configure AWS CLI**
    
    ```bash
    aws configure
    ```
    
    This command will prompt you to enter your AWS Access Key, Secret Key, region, and output format.
    

#### Function Operations

* **Create a Lambda Function**
    
    ```bash
    aws lambda create-function \
      --function-name my-function \
      --runtime python3.8 \
      --role arn:aws:iam::123456789012:role/execution_role \
      --handler lambda_function.lambda_handler \
      --zip-file fileb://function.zip
    ```
    
* **Update a Lambda Function's Code**
    
    ```bash
    aws lambda update-function-code \
      --function-name my-function \
      --zip-file fileb://function.zip
    ```
    
* **Update a Lambda Function's Configuration**
    
    ```bash
    aws lambda update-function-configuration \
      --function-name my-function \
      --handler new_handler \
      --memory-size 256 \
      --timeout 60
    ```
    
* **Delete a Lambda Function**
    
    ```bash
    aws lambda delete-function \
      --function-name my-function
    ```
    

#### Listing and Describing Functions

* **List Lambda Functions**
    
    ```bash
    aws lambda list-functions
    ```
    
* **Get a Lambda Function's Configuration**
    
    ```bash
    aws lambda get-function-configuration \
      --function-name my-function
    ```
    
* **Get a Lambda Function**
    
    ```bash
    aws lambda get-function \
      --function-name my-function
    ```
    

#### Invoking Functions

* **Invoke a Lambda Function**
    
    ```bash
    aws lambda invoke \
      --function-name my-function \
      --payload '{"key1": "value1"}' \
      response.json
    ```
    

#### Permissions and Policies

* **Add Permissions to a Lambda Function**
    
    ```bash
    aws lambda add-permission \
      --function-name my-function \
      --statement-id some-id \
      --action lambda:InvokeFunction \
      --principal s3.amazonaws.com \
      --source-arn arn:aws:s3:::my-bucket
    ```
    
* **Remove Permissions from a Lambda Function**
    
    ```bash
    aws lambda remove-permission \
      --function-name my-function \
      --statement-id some-id
    ```
    

#### Environment Variables

* **Update Environment Variables for a Function**
    
    ```bash
    aws lambda update-function-configuration \
      --function-name my-function \
      --environment Variables={KEY1=value1,KEY2=value2}
    ```
    

#### Versions and Aliases

* **Publish a New Version of a Lambda Function**
    
    ```bash
    aws lambda publish-version \
      --function-name my-function
    ```
    
* **Create an Alias for a Lambda Function Version**
    
    ```bash
    aws lambda create-alias \
      --function-name my-function \
      --name my-alias \
      --function-version 1
    ```
    
* **Update an Alias**
    
    ```bash
    aws lambda update-alias \
      --function-name my-function \
      --name my-alias \
      --function-version 2
    ```
    
* **Delete an Alias**
    
    ```bash
    aws lambda delete-alias \
      --function-name my-function \
      --name my-alias
    ```
    

#### Event Source Mappings

* **Create an Event Source Mapping**
    
    ```bash
    aws lambda create-event-source-mapping \
      --function-name my-function \
      --batch-size 100 \
      --event-source-arn arn:aws:sqs:us-west-2:123456789012:my-queue
    ```
    
* **Update an Event Source Mapping**
    
    ```bash
    aws lambda update-event-source-mapping \
      --uuid 1234abcd-12ab-34cd-56ef-1234567890ab \
      --batch-size 200
    ```
    
* **Delete an Event Source Mapping**
    
    ```bash
    aws lambda delete-event-source-mapping \
      --uuid 1234abcd-12ab-34cd-56ef-1234567890ab
    ```
    

### Useful Options

* **Specify a Region**
    
    ```bash
    aws lambda list-functions --region us-west-2
    ```
    
* **Profile Option**
    
    ```bash
    aws lambda list-functions --profile myprofile
    ```
    

This cheat sheet provides a quick reference to the most commonly used AWS Lambda commands. For more detailed information and additional commands, refer to the [official AWS CLI documentation](https://docs.aws.amazon.com/cli/latest/reference/lambda/index.html).