Question

How do you deploy code to AWS Lambda?

Answer 1

Deploying code to AWS Lambda involves several steps, from writing your code to configuring triggers and managing versions. Here’s a detailed guide on how to deploy your code to AWS Lambda:

1. Write Your Code

Create your Lambda function code using a supported language like Node.js, Python, Java, Go, Ruby, or .NET Core. Ensure your function handler is properly defined according to the runtime requirements.

2. Package Your Code

Package your code along with any dependencies. This can be done in a few ways:

• ZIP File: Compress your code and dependencies into a ZIP file.
• Container Image: Package your code as a Docker container image (supports larger codebases and custom runtimes).

3. Create a Lambda Function

You can create a Lambda function using the AWS Management Console, AWS CLI, AWS SDKs, or Infrastructure as Code (IaC) tools like AWS CloudFormation or AWS SAM (Serverless Application Model).

Using AWS Management Console:

1. Navigate to the AWS Lambda Console: Open the AWS Lambda console.
2. Create Function:
   • Click on “Create function”.
   • Choose “Author from scratch”, “Use a blueprint”, or “Container image”.
   • Fill in the function name, runtime, and execution role.
3. Upload Code:
   • For ZIP file: Under the “Code” section, upload your ZIP file.
   • For Container image: Provide the image URI from Amazon ECR (Elastic Container Registry).

Using AWS CLI:

aws lambda create-function \
    --function-name my-function \
    --runtime python3.8 \
    --role arn:aws:iam::account-id:role/execution-role \
    --handler my_function.handler \
    --zip-file fileb://function.zip 

Using AWS SAM (Serverless Application Model):

1. Create a SAM Template: Define your Lambda function in a template.yaml file.

   Resources:
     MyLambdaFunction:
       Type: AWS::Serverless::Function
       Properties:
         Handler: index.handler
         Runtime: nodejs14.x
         CodeUri: ./src
         MemorySize: 128
         Timeout: 10 

2. Build and Deploy:

   sam build
   sam deploy --guided 

4. Configure Triggers

Configure the events that will trigger your Lambda function. This can be done in the AWS Management Console or via the CLI/IaC tools.

Using AWS Management Console:

1. Add Trigger: In the Lambda function configuration, go to the “Triggers” tab and click “Add trigger”.
2. Select Trigger Source: Choose the AWS service that will trigger the function (e.g., S3, DynamoDB, API Gateway).
3. Configure Trigger: Set up the specific trigger details (e.g., S3 bucket name and event type).

Using AWS CLI:

aws lambda create-event-source-mapping \
    --function-name my-function \
    --event-source-arn arn:aws:s3:::my-bucket \
    --batch-size 100 \
    --starting-position LATEST 

5. Test Your Function

Test your Lambda function to ensure it works correctly. This can be done by:

• Invoking the function manually in the AWS Management Console.
• Using the AWS CLI to invoke the function:

  aws lambda invoke --function-name my-function out.txt 

• Setting up test events and running them in the AWS Management Console.

6. Monitor and Log

Monitor your Lambda function’s performance and view logs:

• CloudWatch Logs: Lambda automatically logs function execution details to CloudWatch Logs.
• CloudWatch Metrics: View function invocation, duration, error rate, and other metrics in CloudWatch.

7. Versioning and Aliases

Manage different versions of your Lambda function:

• Create Version: Publish a new version of your function after testing.

  aws lambda publish-version --function-name my-function 

• Create Alias: Create an alias to point to a specific version.

  aws lambda create-alias --function-name my-function --name PROD --function-version 1 

Example Workflow

1. Write Code: Develop your Lambda function locally.
2. Package: Package your code and dependencies into a ZIP file.
3. Deploy: Use the AWS Management Console, CLI, or SAM to deploy your function.
4. Configure: Set up triggers and permissions.
5. Test: Verify the function works as expected.
6. Monitor: Use CloudWatch to monitor logs and performance.
7. Version: Publish versions and manage aliases for different stages (e.g., dev, prod).

By following these steps, you can deploy and manage your AWS Lambda functions efficiently.