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Top 100 AWS Lambda Interview Questions and Answers

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1. What is AWS Lambda?

AWS Lambda is a serverless computing service that allows you to run code in response to events without the need to provision or manage servers. It automatically scales based on the incoming event rate.

Code Example:

pythonCopy codedef lambda_handler(event, context):
    return "Hello, World!"

Reference: AWS Lambda – Getting Started


2. What are the supported languages for AWS Lambda functions?

AWS Lambda supports multiple programming languages, including Node.js, Python, Java, Go, Ruby, .NET Core, and custom runtimes through the AWS Lambda Runtime API.

Code Example:

pythonCopy code# Example Lambda function in Python
def lambda_handler(event, context):
    return "Hello, World!"

Reference: AWS Lambda Runtimes


3. How does AWS Lambda pricing work?

AWS Lambda pricing is based on the number of requests and the duration of code execution. There’s a free tier for the first one million requests and 400,000 GB-seconds of compute time per month.

Code Example:

pythonCopy code# Example pricing calculation
# Assuming 1 million requests and 100ms execution time
cost = (1e6 * $0.20) + (1e6 * 100ms * $0.00001667)

Reference: AWS Lambda Pricing


4. Explain the concept of an AWS Lambda function handler.

The handler is the method in your code that AWS Lambda calls when an event is triggered. It’s specified as filename.method (for Node.js) or filename::method (for Java) and takes two arguments: event and context.

Code Example (Python):

pythonCopy codedef lambda_handler(event, context):
    return "Hello, World!"

Reference: AWS Lambda Function Handler


5. How do you pass environment variables to an AWS Lambda function?

You can set environment variables in the AWS Lambda console or using the AWS CLI. In Python, access them using os.environ['variable_name'].

Code Example (Python):

pythonCopy codeimport os

def lambda_handler(event, context):
    api_key = os.environ['API_KEY']
    return api_key

Reference: Environment Variables – AWS Lambda


6. Explain the concept of an AWS Lambda execution role.

An execution role grants permissions to an AWS Lambda function to access other AWS services. It’s defined using an IAM role with specific policies attached.

Code Example:

jsonCopy code{
  "Version": "2012-10-17",
  "Statement": [
    {
      "Effect": "Allow",
      "Action": "s3:*",
      "Resource": "arn:aws:s3:::example-bucket/*"
    }
  ]
}

Reference: AWS Lambda Execution Role


7. How do you trigger an AWS Lambda function?

AWS Lambda functions can be triggered by various events, including changes to an S3 bucket, updates to a DynamoDB table, API Gateway requests, SNS notifications, and more.

Code Example:

pythonCopy code# Lambda function triggered by S3 upload event
def lambda_handler(event, context):
    bucket = event['Records'][0]['s3']['bucket']['name']
    key = event['Records'][0]['s3']['object']['key']
    return f"File {key} uploaded to {bucket}"

Reference: AWS Lambda Event Sources


8. Explain the concept of AWS Lambda layers.

AWS Lambda layers are additional packages, libraries, or custom runtimes that can be attached to a function. They allow you to manage common code separately from your function code.

Code Example:

pythonCopy code# Using a layer
import requests
def lambda_handler(event, context):
    response = requests.get('https://example.com')
    return response.text

Reference: AWS Lambda Layers


9. How do you enable logging in an AWS Lambda function?

You can use the print function to log messages to the CloudWatch Logs associated with your function. For more advanced logging, you can use the boto3 library to interact with CloudWatch Logs.

Code Example (Python):

pythonCopy codeimport boto3

def lambda_handler(event, context):
    print("This is a log message")
    return "Hello, World!"

Reference: AWS Lambda Function Logging


11. How can you optimize AWS Lambda functions to reduce cold starts?

  1. Keep Functions Warm: By invoking a function periodically, you can keep it in a warm state, reducing the likelihood of a cold start.

Code Example:

# Using AWS CloudWatch Events to keep a function warm
aws events put-rule --name keep-warm-rule --schedule-expression "rate(5 minutes)"
aws events put-targets --rule keep-warm-rule --targets "Id"="1","Arn"="arn:aws:lambda:us-east-1:123456789012:function:my-function"
  1. Use Provisioned Concurrency: It allows you to reserve a specific number of concurrent executions to ensure low latency.

Code Example (AWS CLI):

aws lambda update-function-configuration --function-name my-function --provisioned-concurrency-config "ProvisionedConcurrentExecutions"=10
  1. Reduce Package Size: Smaller packages load faster, reducing cold start times.

Code Example (Python):

# Exclude unnecessary files from deployment package
$ cd my-function
$ zip -r my-function.zip *
$ aws lambda update-function-code --function-name my-function --zip-file fileb://my-function.zip

Reference: Reducing AWS Lambda Cold Starts


12. How do you handle dependencies in AWS Lambda functions?

You can include dependencies in the deployment package or use layers for common libraries. For complex dependencies, consider packaging them as a custom runtime.

Code Example (Python):

# Including a dependency in deployment package
$ cd my-function
$ pip install requests -t .
$ zip -r my-function.zip *
$ aws lambda update-function-code --function-name my-function --zip-file fileb://my-function.zip

Reference: AWS Lambda Deployment Package


13. Explain the concept of AWS Lambda event sources.

Event sources are services or resources that trigger the execution of a Lambda function. These can include S3 buckets, DynamoDB tables, SNS topics, and more.

Code Example:

# Lambda function triggered by SNS notification
def lambda_handler(event, context):
    message = event['Records'][0]['Sns']['Message']
    return f"Received SNS message: {message}"

Reference: AWS Lambda Event Sources


14. How do you manage permissions for AWS Lambda functions?

You create an execution role with specific policies attached to it. This role grants the function permissions to access other AWS resources.

Code Example:

{
  "Version": "2012-10-17",
  "Statement": [
    {
      "Effect": "Allow",
      "Action": "s3:*",
      "Resource": "arn:aws:s3:::example-bucket/*"
    }
  ]
}

Reference: AWS Lambda Execution Role


15. How can you enable VPC access for an AWS Lambda function?

You can add the function to a VPC by configuring the VPC settings in the function’s configuration. Note that this will affect the function’s internet access.

Code Example:

aws lambda update-function-configuration --function-name my-function --vpc-config "SubnetIds"=["subnet-0123456789abcdef0","subnet-0123456789abcdef1"],"SecurityGroupIds"=["sg-0123456789abcdef0"]

Reference: Using AWS Lambda with Amazon VPC


16. Explain the concept of AWS Lambda destinations.

Lambda destinations allow you to specify a resource (e.g., SNS topic, S3 bucket) where the results of an asynchronous invocation are sent.

Code Example:

aws lambda put-function-event-invoke-config --function-name my-function --destination-config '{"OnSuccess":{"Destination":"arn:aws:sns:us-east-1:123456789012:my-topic"}}'

Reference: AWS Lambda Destinations


17. How can you enable dead-letter queues for an AWS Lambda function?

You can configure a dead-letter queue (DLQ) to capture events that Lambda can’t process. This is useful for troubleshooting and reprocessing.

Code Example (AWS CLI):

aws lambda create-event-source-mapping --function-name my-function --event-source arn:aws:sqs:us-east-1:123456789012:my-queue --batch-size 5 --maximum-batchin-flight-receives 5 --destination-config '{"OnFailure":{"Destination":"arn:aws:sqs:us-east-1:123456789012:my-dlq"}}'

Reference: AWS Lambda Dead-Letter Queues


18. Explain the concept of AWS Lambda concurrency.

Concurrency is the number of requests being served by a function at any given time. It can be managed by adjusting the function’s reserved concurrency or by using provisioned concurrency.

Code Example (AWS CLI):

aws lambda put-function-concurrency --function-name my-function --reserved-concurrent-executions 10

Reference: Managing Concurrency for a Lambda Function


19. How do you enable encryption for an AWS Lambda function?

You can configure encryption at rest for the function’s environment variables and deployment package using AWS Key Management Service (KMS) keys.

Code Example (AWS CLI):

aws lambda create-function-encryption-config --function-name my-function --kms-key-arn arn:aws:kms:us-east-1:123456789012:key/1234abcd-12ab-34cd-56ef-1234567890ab

Reference: AWS Lambda Encryption Configuration


20. Explain the concept of AWS Lambda function versioning and aliases.

Versioning allows you to publish different versions of a function. Aliases are pointers to specific versions or versions with specific configurations.

Code Example (AWS CLI):

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

Reference: AWS Lambda Function Versioning


21. How do you troubleshoot and debug AWS Lambda functions?

  1. CloudWatch Logs: Use print statements in your code to log messages to CloudWatch Logs.

Code Example (Python):

def lambda_handler(event, context):
    print("This is a log message")
    return "Hello, World!"
  1. X-Ray Tracing: Enable AWS X-Ray for distributed tracing and performance analysis.

Code Example (AWS CLI):

aws lambda update-function-configuration --function-name my-function --tracing-config "Mode=Active"
  1. Remote Debugging: For languages like Python, you can use libraries like ptvsd for remote debugging.

Code Example (Python):

# Enable ptvsd for remote debugging
import ptvsd
ptvsd.enable_attach(secret='my_secret', address=('0.0.0.0', 3000))

Reference: AWS Lambda Debugging


22. What is AWS SAM (Serverless Application Model) and how do you use it with AWS Lambda?

AWS SAM is an open-source framework for building serverless applications. It provides a simplified way to define the Amazon API Gateway APIs, AWS Lambda functions, and Amazon DynamoDB tables needed by your serverless application.

Code Example (SAM Template – template.yaml):

Resources:
  MyFunction:
    Type: AWS::Serverless::Function
    Properties:
      Handler: index.handler
      Runtime: nodejs14.x

Reference: AWS SAM Overview


23. How can you deploy AWS Lambda functions using AWS SAM?

  1. Package: Package your AWS SAM application and upload it to an S3 bucket.

Code Example (AWS CLI):

aws cloudformation package --template-file template.yaml --output-template-file packaged.yaml --s3-bucket my-bucket
  1. Deploy: Deploy the packaged template using CloudFormation.

Code Example (AWS CLI):

aws cloudformation deploy --template-file packaged.yaml --stack-name my-stack --capabilities CAPABILITY_IAM

Reference: AWS SAM CLI – Deploy


24. How can you enable AWS Lambda function versioning in AWS SAM?

You can define a AWS::Lambda::Alias resource in your SAM template to create aliases for specific function versions.

Code Example (SAM Template – template.yaml):

Resources:
  MyFunction:
    Type: AWS::Serverless::Function
    Properties:
      Handler: index.handler
      Runtime: nodejs14.x
  MyAlias:
    Type: AWS::Lambda::Alias
    Properties:
      FunctionName: !Ref MyFunction
      FunctionVersion: !GetAtt MyFunction.Version
      Name: PROD

Reference: AWS SAM Function Resource Properties


25. Explain the concept of AWS Lambda environment variables.

Environment variables are key-value pairs that you can configure for your function. They can be accessed in your code and are useful for storing configuration data.

Code Example (Python):

import os

def lambda_handler(event, context):
    api_key = os.environ['API_KEY']
    return api_key

Reference: AWS Lambda Environment Variables


26. How do you handle retries and error handling in AWS Lambda functions?

You can implement retries and error handling in your code. For example, you can catch exceptions and retry the operation.

Code Example (Python):

import time

def lambda_handler(event, context):
    max_retries = 3
    retries = 0

    while retries < max_retries:
        try:
            # Code that may raise an exception
            result = 1 / 0
            return result
        except Exception as e:
            print(f"An error occurred: {e}")
            retries += 1
            time.sleep(2)  # Add a delay before retrying

    return "Max retries reached"

Reference: AWS Lambda Retries and Errors


27. How do you control the execution timeout for an AWS Lambda function?

You can set the timeout parameter when creating or updating a Lambda function. The maximum value is 900 seconds (15 minutes).

Code Example (AWS CLI):

aws lambda create-function --function-name my-function --runtime nodejs14.x --handler index.handler --role arn:aws:iam::123456789012:role/service-role/MyRole --timeout 60 --zip-file fileb://my-function.zip

Reference: AWS Lambda Function Configuration


28. Explain the concept of AWS Lambda resource-based policies.

Resource-based policies are permissions policies that you can attach to AWS Lambda functions, layers, and APIs. They define what other AWS services can invoke your function.

Code Example (AWS CLI):

aws lambda add-permission --function-name my-function --statement-id my-statement --action lambda:InvokeFunction --principal s3.amazonaws.com --source-arn arn:aws:s3:::my-bucket --source-account 123456789012

Reference: AWS Lambda Resource Policies


29. How do you manage concurrency for an AWS Lambda function in AWS SAM?

You can specify the ReservedConcurrentExecutions property in your SAM template to set a concurrency limit for your function.

Code Example (SAM Template – template.yaml):

Resources:
  MyFunction:
    Type: AWS::Serverless::Function
    Properties:
      Handler: index.handler
      Runtime: nodejs14.x
      ReservedConcurrentExecutions: 10

Reference: AWS SAM Function Resource Properties


30. Explain the concept of AWS Lambda deployment preferences.

AWS Lambda deployment preferences allow you to control how traffic is shifted between two function versions when you update a function alias.

Code Example (AWS CLI):

aws lambda put-function-alias --function-name my-function --name PROD --function-version 2 --routing-config AdditionalVersionWeights={"2"=0.9,"3"=0.1}

Reference: AWS Lambda Deployment Preferences


31. How do you manage environment-specific configurations in AWS Lambda functions?

You can use environment variables to store configuration values that vary between environments (e.g., dev, test, prod).

Code Example (Python):

import os

def lambda_handler(event, context):
    env = os.environ.get('ENVIRONMENT')
    if env == 'dev':
        # Use dev configurations
    elif env == 'prod':
        # Use prod configurations
    else:
        # Use default configurations

Reference: AWS Lambda Environment Variables


32. How do you implement a custom runtime for an AWS Lambda function?

You can package your custom runtime and specify it in the Runtime property of your function.

Code Example (SAM Template – template.yaml):

Resources:
  MyFunction:
    Type: AWS::Serverless::Function
    Properties:
      Handler: index.handler
      Runtime: provided
      Layers:
        - arn:aws:lambda:us-east-1:123456789012:layer:my-custom-runtime-layer:1

Reference: Creating a Custom Runtime


33. How do you manage secrets and sensitive information in AWS Lambda functions?

You can use AWS Systems Manager Parameter Store or AWS Secrets Manager to securely store and retrieve sensitive information.

Code Example (Python – Using AWS Systems Manager Parameter Store):

import boto3

def lambda_handler(event, context):
    ssm = boto3.client('ssm')
    response = ssm.get_parameter(Name='my-secret', WithDecryption=True)
    secret_value = response['Parameter']['Value']
    return secret_value

Reference: AWS Systems Manager Parameter Store


34. Explain the concept of AWS Lambda environment contexts.

Lambda environment contexts provide information about the execution environment, including details like function name, memory size, request ID, and execution deadline.

Code Example (Python):

def lambda_handler(event, context):
    print(f"Function name: {context.function_name}")
    print(f"Memory limit (MB): {context.memory_limit_in_mb}")
    print(f"Request ID: {context.aws_request_id}")
    print(f"Remaining time (ms): {context.get_remaining_time_in_millis()}")

Reference: AWS Lambda Context Object


35. How do you enable AWS Lambda function insights?

You can enable AWS Lambda function insights to gain visibility into the performance of your functions.

Code Example (AWS CLI):

aws lambda update-function-configuration --function-name my-function --tracing-config "Mode=Active"

Reference: AWS Lambda Function Insights


36. Explain the concept of AWS Lambda event payload.

The event payload is the input data that triggers a Lambda function. It can be structured JSON or other formats depending on the event source.

Code Example (Python – S3 Event):

def lambda_handler(event, context):
    for record in event['Records']:
        bucket = record['s3']['bucket']['name']
        key = record['s3']['object']['key']
        print(f"New object added to bucket '{bucket}': '{key}'")

Reference: AWS Lambda Event Payload


37. How can you use AWS Lambda with Amazon EventBridge?

You can set up rules in EventBridge to route events to Lambda functions based on defined conditions.

Code Example (AWS CLI – Creating a Rule):

aws events put-rule --name my-rule --event-pattern '{"source": ["aws.s3"],"detail": {"eventName": ["PutObject"]}}'
aws events put-targets --rule my-rule --targets "Id"="1","Arn"="arn:aws:lambda:us-east-1:123456789012:function:my-function"

Reference: Using AWS Lambda with Amazon EventBridge


38. How do you use AWS Lambda with Amazon API Gateway?

You can create an API Gateway API and integrate it with a Lambda function to expose it as an HTTP endpoint.

Code Example (AWS CLI):

aws apigateway create-rest-api --name my-api
aws apigateway create-resource --rest-api-id <api-id> --parent-id <parent-resource-id> --path-part my-resource
aws apigateway put-method --rest-api-id <api-id> --resource-id <resource-id> --http-method GET --authorization-type NONE
aws apigateway put-integration --rest-api-id <api-id> --resource-id <resource-id> --http-method GET --type AWS_PROXY --uri arn:aws:apigateway:<region>:lambda:path/2015-03-31/functions/<function-arn>/invocations
aws apigateway create-deployment --rest-api-id <api-id> --stage-name prod

Reference: Using AWS Lambda with Amazon API Gateway


39. How do you handle binary data in AWS Lambda functions?

You can handle binary data by using base64 encoding/decoding in your function code.

Code Example (Python – Handling Binary Data):

import base64

def lambda_handler(event, context):
    # Convert binary data to base64 string
    binary_data = b'hello'
    base64_data = base64.b64encode(binary_data).decode('utf-8')
    return base64_data

Reference: Handling Binary Data in AWS Lambda


40. How do you enable cross-account access for an AWS Lambda function?

You can create a resource policy to allow specific accounts or principals to invoke your function.

Code Example (AWS CLI):

aws lambda add-permission --function-name my-function --statement-id my-statement --action lambda:InvokeFunction --principal arn:aws:iam::123456789012:role/MyRole

Reference: AWS Lambda Resource Policies


41. Explain the concept of AWS Lambda function layers.

Layers are distribution mechanisms for libraries, custom runtimes, and other function dependencies. They let you manage your in-development function code independently from the unchanging code and resources that it uses.

Code Example (AWS CLI):

aws lambda publish-layer-version --layer-name my-layer --zip-file fileb://my-layer.zip

Reference: AWS Lambda Layers


42. How do you enable custom logging for an AWS Lambda function?

You can use AWS CloudWatch Logs Insights to query and analyze log data.

Code Example (Python):

import logging

logger = logging.getLogger()
logger.setLevel(logging.INFO)

def lambda_handler(event, context):
    logger.info('This is a custom log message')

Reference: AWS Lambda Logging


43. How do you perform blue-green deployments for AWS Lambda functions?

You can use aliases and versioning to implement blue-green deployments.

Code Example (AWS CLI – Blue-Green Deployment):

# Publish a new version
aws lambda publish-version --function-name my-function

# Update the alias to point to the new version
aws lambda update-alias --function-name my-function --name PROD --function-version 2

Reference: AWS Lambda Function Versioning


44. Explain the concept of AWS Lambda destination configurations.

Destination configurations allow you to send invocation records to an Amazon SNS topic, Amazon SQS queue, or AWS Lambda function for further processing.

Code Example (AWS CLI):

aws lambda put-function-event-invoke-config --function-name my-function --destination-config '{"OnSuccess":{"Destination":"arn:aws:sqs:us-east-1:123456789012:my-queue"}}'

Reference: AWS Lambda Destinations


45. How do you use AWS Lambda with Amazon S3 events?

You can configure an S3 bucket to send events to a Lambda function when objects are created, modified, or deleted.

Code Example (AWS CLI – Creating an S3 Event Source):

aws s3api put-bucket-notification-configuration --bucket my-bucket --notification-configuration '{"LambdaFunctionConfigurations":[{"Id":"1","LambdaFunctionArn":"arn:aws:lambda:us-east-1:123456789012:function:my-function","Events":["s3:ObjectCreated:*"]}]}'

Reference: Using AWS Lambda with Amazon S3


46. How do you handle long-running tasks in AWS Lambda functions?

For tasks that exceed the maximum execution time, you can use Step Functions to orchestrate multiple Lambda functions.

Code Example (AWS Step Functions – State Definition):

{
  "Type": "Task",
  "Resource": "arn:aws:lambda:us-east-1:123456789012:function:my-function",
  "End": true
}

Reference: AWS Step Functions


47. How do you use AWS Lambda with Amazon DynamoDB streams?

You can configure a DynamoDB stream to send events to a Lambda function when records are inserted, updated, or deleted.

Code Example (AWS CLI – Creating a DynamoDB Stream Event Source):

aws lambda create-event-source-mapping --function-name my-function --event-source-arn arn:aws:dynamodb:us-east-1:123456789012:table/my-table/stream/2021-10-01T00:00:00.000

Reference: Using AWS Lambda with Amazon DynamoDB


48. How do you trigger an AWS Lambda function using an HTTP request?

You can use Amazon API Gateway to create an HTTP endpoint that triggers a Lambda function.

Code Example (AWS CLI):

aws apigateway create-rest-api --name my-api
aws apigateway create-resource --rest-api-id <api-id> --parent-id <parent-resource-id> --path-part my-resource
aws apigateway put-method --rest-api-id <api-id> --resource-id <resource-id> --http-method POST --authorization-type NONE
aws apigateway put-integration --rest-api-id <api-id> --resource-id <resource-id> --http-method POST --type AWS_PROXY --uri arn:aws:apigateway:<region>:lambda:path/2015-03-31/functions/<function-arn>/invocations
aws apigateway create-deployment --rest-api-id <api-id> --stage-name prod

Reference: Using AWS Lambda with Amazon API Gateway


49. How do you manage permissions for an AWS Lambda function?

You can use IAM roles, resource policies, and execution policies to control what resources your Lambda function can access.

Code Example (AWS CLI – Adding Permission):

aws lambda add-permission --function-name my-function --statement-id my-statement --action lambda:InvokeFunction --principal s3.amazonaws.com --source-arn arn:aws:s3:::my-bucket --source-account 123456789012

Reference: AWS Lambda Permissions Model


50. How do you handle errors and retries in AWS Lambda functions?

You can implement error handling in your function code and configure retry behavior using Dead Letter Queues (DLQs).

Code Example (Python – Error Handling):

def lambda_handler(event, context):
    try:
        # Function code
    except Exception as e:
        # Handle error
        raise e

Reference: AWS Lambda Error Handling


51. How do you set up VPC configurations for an AWS Lambda function?

You can configure a Lambda function to connect to resources in a VPC by specifying a VPC and subnet IDs.

Code Example (AWS CLI – Updating Function Configuration):

aws lambda update-function-configuration --function-name my-function --vpc-config "SubnetIds"=["subnet-12345678","subnet-23456789"],"SecurityGroupIds"=["sg-12345678"]

Reference: AWS Lambda VPC Configuration


52. How do you monitor AWS Lambda functions?

You can use Amazon CloudWatch to monitor Lambda functions, including metrics, logs, and custom metrics.

Code Example (AWS CLI – Creating CloudWatch Alarms):

aws cloudwatch put-metric-alarm --alarm-name my-alarm --metric-name Invocations --namespace AWS/Lambda --statistic SampleCount --period 300 --evaluation-periods 1 --threshold 100 --comparison-operator GreaterThanThreshold --alarm-actions arn:aws:sns:us-east-1:123456789012:my-topic

Reference: Monitoring AWS Lambda with Amazon CloudWatch


53. How do you use AWS Lambda with Amazon Kinesis Data Streams?

You can configure a Kinesis Data Stream to send events to a Lambda function for processing.

Code Example (AWS CLI – Creating a Kinesis Event Source):

aws lambda create-event-source-mapping --function-name my-function --event-source-arn arn:aws:kinesis:us-east-1:123456789012:stream/my-stream

Reference: Using AWS Lambda with Amazon Kinesis Data Streams


54. How do you perform A/B testing with AWS Lambda functions?

You can use aliases to route a portion of incoming requests to different versions of your function.

Code Example (AWS CLI – Updating Alias Configuration):

aws lambda update-alias --function-name my-function --name PROD --routing-config AdditionalVersionWeights={version2=0.2}

Reference: AWS Lambda Function Aliases


55. How do you automate deployments for AWS Lambda functions?

You can use AWS SAM (Serverless Application Model) to define, package, and deploy serverless applications.

Code Example (AWS SAM Template – template.yaml):

AWSTemplateFormatVersion: '2010-09-09'
Transform: AWS::Serverless-2016-10-31
Resources:
  MyFunction:
    Type: AWS::Serverless::Function
    Properties:
      Handler: index.handler
      Runtime: python3.8
      Role: arn:aws:iam::123456789012:role/MyRole
      CodeUri: .
      Events:
        MyEvent:
          Type: Api
          Properties:
            Path: /my-endpoint
            Method: get

Reference: AWS SAM


56. How do you implement authentication and authorization for AWS Lambda functions?

You can use AWS Identity and Access Management (IAM) roles and policies to control who can invoke your Lambda function.

Code Example (AWS CLI – Adding Permission):

aws lambda add-permission --function-name my-function --statement-id my-statement --action lambda:InvokeFunction --principal arn:aws:iam::123456789012:role/MyRole

Reference: AWS Lambda Permissions Model


57. How do you use AWS Lambda with Amazon SNS (Simple Notification Service)?

You can configure an SNS topic to trigger a Lambda function when a new message is published.

Code Example (AWS CLI – Creating an SNS Event Source):

aws lambda create-event-source-mapping --function-name my-function --event-source-arn arn:aws:sns:us-east-1:123456789012:my-topic

Reference: Using AWS Lambda with Amazon SNS


58. How do you manage concurrent executions for AWS Lambda functions?

You can configure concurrency limits to control the number of simultaneous function executions.

Code Example (AWS CLI – Setting Concurrency Limit):

aws lambda put-function-concurrency --function-name my-function --reserved-concurrent-executions 5

Reference: Managing Concurrency for a Lambda Function


59. How do you perform load testing on AWS Lambda functions?

You can use tools like AWS Lambda Power Tuning or create custom scripts to simulate a large number of concurrent invocations.

Code Example (AWS Lambda Power Tuning):

npx lambda-power-tuning --function-name my-function --num 1000 --payload payload.json --duration 60

Reference: AWS Lambda Power Tuning


60. How do you use AWS Lambda with Amazon EventBridge for event-driven architectures?

You can create rules in EventBridge to route events from various sources to Lambda functions for processing.

Code Example (AWS CLI – Creating a Rule):

aws events put-rule --name my-rule --event-pattern '{"source": ["aws.s3"],"detail": {"eventName": ["PutObject"]}}'
aws events put-targets --rule my-rule --targets "Id"="1","Arn"="arn:aws:lambda:us-east-1:123456789012:function:my-function"

Reference: Using AWS Lambda with Amazon EventBridge


61. How do you enable AWS X-Ray tracing for AWS Lambda functions?

You can enable X-Ray tracing to gain insights into the performance of your functions.

Code Example (AWS CLI):

aws lambda update-function-configuration --function-name my-function --tracing-config "Mode=Active"

Reference: AWS Lambda Function Insights


62. How do you manage environment variables for an AWS Lambda function?

You can use environment variables to store configuration values that can be accessed by your function code.

Code Example (AWS CLI – Updating Environment Variables):

aws lambda update-function-configuration --function-name my-function --environment "Variables={ENV_VAR=value}"

Reference: AWS Lambda Environment Variables


63. How do you manage secrets and sensitive data in AWS Lambda functions?

You can use AWS Secrets Manager or AWS Systems Manager Parameter Store to securely store and retrieve sensitive information in your Lambda functions.

Code Example (Python – Accessing Secrets from AWS Secrets Manager):

import boto3
import json

secrets_client = boto3.client('secretsmanager')

def lambda_handler(event, context):
    secret_name = "my-secret"
    response = secrets_client.get_secret_value(SecretId=secret_name)
    secret_data = json.loads(response['SecretString'])
    # Use secret_data in your code

Reference: Storing and Retrieving Secrets in AWS Lambda


64. How do you optimize the cold start time of AWS Lambda functions?

You can use provisioned concurrency and optimize your code to reduce initialization time.

Code Example (AWS CLI – Setting Provisioned Concurrency):

aws lambda update-function-configuration --function-name my-function --provisioned-concurrency-config "ProvisionedConcurrentExecutions=10"

Reference: Optimizing AWS Lambda Cold Start


65. How do you implement asynchronous processing with AWS Lambda?

You can use AWS Step Functions or Amazon SQS to queue and process asynchronous tasks.

Code Example (AWS Step Functions – State Definition):

{
  "Type": "Task",
  "Resource": "arn:aws:lambda:us-east-1:123456789012:function:my-function",
  "End": true
}

Reference: Asynchronous Processing with AWS Lambda


66. How do you handle large payloads in AWS Lambda functions?

You can use Amazon S3 to store and retrieve large payloads, passing only references to the S3 objects to your function.

Code Example (Python – Accessing Large Payloads from S3):

import boto3

s3_client = boto3.client('s3')

def lambda_handler(event, context):
    bucket = event['bucket']
    key = event['key']
    response = s3_client.get_object(Bucket=bucket, Key=key)
    payload = response['Body'].read()
    # Process payload

Reference: Handling Large Payloads in AWS Lambda


67. How do you schedule AWS Lambda functions to run at specific times?

You can use Amazon CloudWatch Events to schedule Lambda functions using cron expressions.

Code Example (AWS CLI – Creating a CloudWatch Rule):

aws events put-rule --name my-rule --schedule-expression "cron(0 12 * * ? *)"
aws events put-targets --rule my-rule --targets "Id"="1","Arn"="arn:aws:lambda:us-east-1:123456789012:function:my-function"

Reference: Scheduling AWS Lambda Functions


68. How do you use AWS Lambda with Amazon Elasticsearch Service?

You can use the AWS SDKs to interact with Elasticsearch clusters from your Lambda functions.

Code Example (Python – Elasticsearch Query):

import boto3
from elasticsearch import Elasticsearch, RequestsHttpConnection
from requests_aws4auth import AWS4Auth

def lambda_handler(event, context):
    es_host = "your-es-endpoint"
    region = "us-east-1"
    service = "es"

    session = boto3.session.Session()
    credentials = session.get_credentials()
    awsauth = AWS4Auth(credentials.access_key, credentials.secret_key, region, service, session_token=credentials.token)

    es = Elasticsearch(
        hosts=[{'host': es_host, 'port': 443}],
        http_auth=awsauth,
        use_ssl=True,
        verify_certs=True,
        connection_class=RequestsHttpConnection
    )

    response = es.search(index="my-index", body={"query": {"match_all": {}}})
    # Process response

Reference: Using AWS Lambda with Amazon Elasticsearch Service


69. How do you secure AWS Lambda functions in a multi-tenant environment?

You can implement security measures such as VPCs, IAM policies, and resource policies to isolate and control access to resources in a multi-tenant environment.

Code Example (AWS CLI – Resource Policy):

aws lambda add-permission --function-name my-function --statement-id my-statement --action lambda:InvokeFunction --principal "*" --source-arn arn:aws:execute-api:us-east-1:123456789012:my-api/*/GET/my-resource

Reference: Securing AWS Lambda in Multi-Tenant Environments


70. How do you manage dependencies and packages in AWS Lambda functions?

You can package your function code along with its dependencies in a deployment package or use AWS Lambda Layers for common libraries.

Code Example (AWS CLI – Creating a Deployment Package):

zip my-function.zip my-function.py my-dependency

Reference: AWS Lambda Deployment Packages


71. How do you handle binary data in AWS Lambda functions?

You can base64 encode binary data before passing it as an input to your function, and decode it within the function.

Code Example (Python – Handling Binary Data):

import base64

def lambda_handler(event, context):
    encoded_data = event['binaryData']
    binary_data = base64.b64decode(encoded_data)
    # Process binary data

Reference: Handling Binary Data in AWS Lambda


72. How do you use AWS Lambda with Amazon DynamoDB for database operations?

You can use the AWS SDKs to interact with DynamoDB tables from your Lambda functions.

Code Example (Python – DynamoDB Put Item):

import boto3

dynamodb = boto3.client('dynamodb')

def lambda_handler(event, context):
    table_name = "my-table"
    item = {
        'PK': {'S': '1234'},
        'SK': {'S': '5678'},
        'Attribute1': {'S': 'Value1'},
        'Attribute2': {'N': '42'}
    }
    dynamodb.put_item(TableName=table_name, Item=item)

Reference: Using AWS Lambda with Amazon DynamoDB


73. How do you automate the deployment of AWS Lambda functions?

You can use AWS SAM, AWS CDK, or CI/CD pipelines with tools like AWS CodePipeline and AWS CodeDeploy for automated deployments.

Code Example (AWS CDK – Python):

from aws_cdk import (
    aws_lambda as _lambda,
    aws_events as events,
    aws_events_targets as targets,
    core
)

class MyLambdaStack(core.Stack):

    def __init__(self, scope: core.Construct, id: str, **kwargs) -> None:
        super().__init__(scope, id, **kwargs)

        my_lambda = _lambda.Function(
            self, 'MyLambda',
            runtime=_lambda.Runtime.PYTHON_3_8,
            handler='index.handler',
            code=_lambda.Code.from_asset('path/to/code')
        )

        rule = events.Rule(
            self, 'Rule',
            schedule=events.Schedule.rate(core.Duration.minutes(1))
        )

        rule.add_target(targets.LambdaFunction(my_lambda))

Reference: Automating AWS Lambda Deployments


74. How do you handle cross-region invocations with AWS Lambda functions?

You can configure the destination region and specify the function ARN of the remote region for cross-region invocations.

Code Example (AWS CLI – Configuring Cross-Region Invocation):

aws lambda update-function-configuration --function-name my-function --region us-west-2 --destination-config "OnSuccess=arn:aws:lambda:us-east-1:123456789012:function:my-remote-function"

Reference: Cross-Region Invocations with AWS Lambda


75. How do you implement canary deployments with AWS Lambda functions?

You can use AWS Lambda aliases and weighted alias traffic shifting to gradually roll out a new version.

Code Example (AWS CLI – Updating Alias Weights):

aws lambda update-alias --function-name my-function --name PROD --routing-config AdditionalVersionWeights={version2=0.1,version3=0.9}

Reference: Canary Deployments with AWS Lambda Aliases


76. How do you implement retries with exponential backoff in AWS Lambda functions?

You can implement exponential backoff logic in your function code to handle transient errors.

Code Example (Python – Exponential Backoff):

import time

def lambda_handler(event, context):
    max_retries = 3
    retries = 0
    while retries < max_retries:
        try:
            # Function code
            break
        except Exception as e:
            retries += 1
            if retries == max_retries:
                raise e
            else:
                backoff_time = 2 ** retries
                time.sleep(backoff_time)

Reference: Handling Retries in AWS Lambda


77. How do you implement long-polling with AWS Lambda functions?

You can use services like Amazon SQS or Amazon DynamoDB Streams for long-polling scenarios.

Code Example (AWS SDK – Long-Polling with SQS):

import boto3

sqs = boto3.client('sqs')

def lambda_handler(event, context):
    queue_url = 'https://sqs.us-east-1.amazonaws.com/123456789012/my-queue'
    response = sqs.receive_message(QueueUrl=queue_url, WaitTimeSeconds=20)
    messages = response.get('Messages', [])
    for message in messages:
        # Process message

Reference: Long-Polling with Amazon SQS


78. How do you handle versioning and rollback of AWS Lambda functions?

You can use aliases and versioning to manage different versions of your function and easily switch between them.

Code Example (AWS CLI – Creating a Version):

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

Reference: AWS Lambda Versioning and Aliases


79. How do you implement cross-account access for AWS Lambda functions?

You can use IAM roles with permissions allowing cross-account access, and grant necessary permissions to the source account.

Code Example (AWS CLI – Assume Role Policy):

aws iam create-role --role-name CrossAccountRole --assume-role-policy-document file://cross-account-policy.json

Reference: Cross-Account Access with AWS Lambda


80. How do you use AWS Lambda with Amazon S3 for file processing?

You can configure an S3 bucket to trigger a Lambda function when a new object is uploaded.

Code Example (AWS CLI – Creating an S3 Event Source):

aws lambda create-event-source-mapping --function-name my-function --event-source-arn arn:aws:s3:::my-bucket

Reference: Using AWS Lambda with Amazon S3


81. How do you capture and process logs in AWS Lambda functions?

You can use CloudWatch Logs to capture logs from your Lambda functions. Additionally, you can use the AWS SDKs to interact with logs programmatically.

Code Example (Python – Logging in Lambda):

import logging

def lambda_handler(event, context):
    logger = logging.getLogger()
    logger.setLevel(logging.INFO)
    logger.info('This is an example log message')

Reference: Logging in AWS Lambda


82. How do you implement custom metrics and monitoring for AWS Lambda functions?

You can use CloudWatch custom metrics and create custom dashboards to monitor specific aspects of your Lambda functions.

Code Example (Python – Publishing Custom Metric):

import boto3

cloudwatch = boto3.client('cloudwatch')

def lambda_handler(event, context):
    metric_name = 'CustomMetric'
    value = 42

    cloudwatch.put_metric_data(
        MetricData=[
            {
                'MetricName': metric_name,
                'Value': value,
                'Unit': 'Count',
                'Dimensions': [
                    {
                        'Name': 'FunctionName',
                        'Value': context.function_name
                    }
                ]
            },
        ],
        Namespace='CustomNamespace'
    )

Reference: Custom Metrics in AWS Lambda


83. How do you manage environment variables in AWS Lambda functions?

You can use environment variables to pass configuration values to your Lambda functions.

Code Example (AWS CLI – Setting Environment Variables):

aws lambda update-function-configuration --function-name my-function --environment "Variables={KEY1=value1,KEY2=value2}"

Reference: Environment Variables in AWS Lambda


84. How do you implement canary testing for AWS Lambda functions?

You can use AWS Step Functions or a custom deployment strategy to perform canary testing.

Code Example (AWS Step Functions – Canary Testing State Definition):

{
  "Type": "Task",
  "Resource": "arn:aws:lambda:us-east-1:123456789012:function:my-function",
  "End": true
}

Reference: Canary Testing with AWS Lambda


85. How do you secure sensitive information in environment variables?

You can use AWS Secrets Manager or AWS Systems Manager Parameter Store to securely store sensitive data and retrieve it in your Lambda function.

Code Example (Python – Accessing Secrets from AWS Secrets Manager):

import boto3
import json

secrets_client = boto3.client('secretsmanager')

def lambda_handler(event, context):
    secret_name = "my-secret"
    response = secrets_client.get_secret_value(SecretId=secret_name)
    secret_data = json.loads(response['SecretString'])
    # Use secret_data in your code

Reference: Storing and Retrieving Secrets in AWS Lambda


86. How do you handle cross-region replication of AWS Lambda functions?

You can use services like AWS SAM, AWS CDK, or custom scripts to automate the deployment of functions across regions.

Code Example (AWS CLI – Deploying Function to Multiple Regions):

aws lambda create-function --function-name my-function --region us-west-2 --code S3Bucket=my-bucket,S3Key=my-zipfile --role arn:aws:iam::123456789012:role/execution-role

Reference: Cross-Region Replication with AWS Lambda


87. How do you implement fine-grained access control for AWS Lambda functions?

You can use IAM policies to grant specific permissions to your Lambda functions and control who can invoke them.

Code Example (AWS CLI – Adding IAM Permissions):

aws lambda add-permission --function-name my-function --statement-id my-statement --principal s3.amazonaws.com --action lambda:InvokeFunction --source-arn arn:aws:s3:::my-bucket

Reference: Fine-Grained Access Control for AWS Lambda


88. How do you perform load testing on AWS Lambda functions?

You can use tools like AWS Lambda Power Tuning or custom scripts to simulate a large number of invocations.

Code Example (Python – Simulating Load with Threading):

import threading
import boto3

lambda_client = boto3.client('lambda')

def invoke_function():
    response = lambda_client.invoke(FunctionName='my-function')
    # Process response

for _ in range(100):
    threading.Thread(target=invoke_function).start()

Reference: Load Testing AWS Lambda


89. How do you handle dependencies with native extensions in AWS Lambda functions?

You can build dependencies in an environment similar to the AWS Lambda execution environment, and package them with your function.

Code Example (AWS CLI – Packaging Dependencies):

docker run -v "$PWD":/var/task "lambci/lambda:build-python3.8" /bin/sh -c "pip install -r requirements.txt -t python/lib/python3.8/site-packages/; exit"
zip -r my-function.zip python

Reference: Including Libraries in a Deployment Package


90. How do you trigger AWS Lambda functions in response to custom events?

You can use services like Amazon EventBridge or Amazon SNS to send custom events that trigger your Lambda functions.

Code Example (AWS EventBridge – Creating a Rule):

aws events put-rule --name my-rule --event-pattern "{\"source\":[\"custom.source\"],\"detail-type\":[\"custom.event\"]}"
aws events put-targets --rule my-rule --targets "Id"="1","Arn"="arn:aws:lambda:us-east-1:123456789012:function:my-function"

Reference: Custom Event Triggers for AWS Lambda


91. How do you implement transactional operations in AWS Lambda functions?

You can use services like Amazon DynamoDB Transactions to perform atomic, consistent, isolated, and durable operations.

Code Example (Python – DynamoDB Transactions):

import boto3

dynamodb = boto3.client('dynamodb')

def lambda_handler(event, context):
    with dynamodb.transact_write_items(
        TransactItems=[
            {
                'Update': {
                    'TableName': 'my-table',
                    'Key': {'PK': {'S': '1234'}, 'SK': {'S': '5678'}},
                    'UpdateExpression': 'SET Attribute1 = :val1',
                    'ExpressionAttributeValues': {':val1': {'S': 'NewValue'}}
                }
            }
        ]
    ) as response:
        # Process response

Reference: DynamoDB Transactions in AWS Lambda


92. How do you implement asynchronous processing with AWS Lambda functions?

You can use Amazon SNS or Amazon SQS to decouple the producer of an event from the processing Lambda function.

Code Example (AWS CLI – Configuring Asynchronous Invocation):

aws lambda update-function-configuration --function-name my-function --event-config '{"EventSourceArn": "arn:aws:sqs:us-east-1:123456789012:my-queue", "EventType": "Sqs"}'

Reference: Asynchronous Invocation of AWS Lambda Functions


93. How do you implement custom error handling in AWS Lambda functions?

You can use try-except blocks or custom error handling logic within your function code.

Code Example (Python – Custom Error Handling):

def lambda_handler(event, context):
    try:
        # Function code
    except Exception as e:
        error_message = str(e)
        # Custom error handling logic

Reference: Error Handling in AWS Lambda


94. How do you optimize cold start performance in AWS Lambda functions?

You can use techniques like provisioned concurrency, optimizing your deployment package size, and minimizing initialization code.

Code Example (AWS CLI – Provisioned Concurrency):

aws lambda update-function-configuration --function-name my-function --provisioned-concurrency-config '{"ProvisionedConcurrentExecutions": 10}'

Reference: Optimizing AWS Lambda Cold Starts


95. How do you handle large payloads in AWS Lambda functions?

You can use Amazon S3 to store and retrieve large payloads, and pass references to S3 objects as input to your function.

Code Example (Python – Handling Large Payloads):

import boto3

s3 = boto3.client('s3')

def lambda_handler(event, context):
    bucket = event['bucket']
    key = event['key']
    response = s3.get_object(Bucket=bucket, Key=key)
    body = response['Body'].read()
    # Process body

Reference: Handling Large Payloads with AWS Lambda


96. How do you implement a custom VPC configuration for AWS Lambda functions?

You can configure a VPC for your Lambda function to access resources in a specific Virtual Private Cloud.

Code Example (AWS CLI – Configuring VPC):

aws lambda update-function-configuration --function-name my-function --vpc-config SubnetIds=subnet-1234,subnet-5678,SecurityGroupIds=sg-1234

Reference: Configuring a VPC for AWS Lambda


97. How do you implement a dead-letter queue for AWS Lambda functions?

You can configure an Amazon SNS topic or an Amazon SQS queue as a dead-letter queue to capture events that your function can’t process.

Code Example (AWS CLI – Configuring Dead-Letter Queue):

aws lambda update-function-configuration --function-name my-function --dead-letter-config TargetArn=arn:aws:sns:us-east-1:123456789012:my-dlq

Reference: Dead-Letter Queues for AWS Lambda


98. How do you implement cross-service transactions with AWS Lambda functions?

You can use services like Amazon Step Functions or Amazon EventBridge to orchestrate cross-service transactions.

Code Example (Amazon Step Functions – State Definition):

{
  "StartAt": "InvokeLambda1",
  "States": {
    "InvokeLambda1": {
      "Type": "Task",
      "Resource": "arn:aws:lambda:us-east-1:123456789012:function:my-function1",
      "End": true
    },
    "InvokeLambda2": {
      "Type": "Task",
      "Resource": "arn:aws:lambda:us-east-1:123456789012:function:my-function2",
      "End": true
    }
  }
}

Reference: Implementing Cross-Service Transactions


99. How do you implement versioning and aliases for AWS Lambda functions?

You can create versions and aliases for your functions to manage deployments and control traffic shifting.

Code Example (AWS CLI – Creating a Version and Alias):

aws lambda publish-version --function-name my-function
aws lambda create-alias --function-name my-function --name prod --function-version 1

Reference: AWS Lambda Function Versioning and Aliases


100. How do you implement cross-account access for AWS Lambda functions?

You can use resource-based policies to grant permissions to another AWS account to invoke your Lambda function.

Code Example (AWS CLI – Adding Resource Policy):

aws lambda add-permission --function-name my-function --statement-id my-statement --action lambda:InvokeFunction --principal 123456789012

Reference: Cross-Account Access for AWS Lambda