Serverless Architecture Samples

// AWS Lambda Hello World Example
exports.handler = async (event) => {
    console.log('Event: ', JSON.stringify(event, null, 2));

    const response = {
        statusCode: 200,
        headers: {
            'Content-Type': 'application/json',
            'Access-Control-Allow-Origin': '*',
        },
        body: JSON.stringify({
            message: 'Hello from AWS Lambda!',
            input: event,
            timestamp: new Date().toISOString(),
        }),
    };

    return response;
};

// Handler with different HTTP methods
exports.apiHandler = async (event) => {
    const httpMethod = event.httpMethod;
    const path = event.path;

    switch (httpMethod) {
        case 'GET':
            return {
                statusCode: 200,
                body: JSON.stringify({
                    message: 'GET request received',
                    path: path,
                }),
            };
        case 'POST':
            const requestBody = JSON.parse(event.body);
            return {
                statusCode: 201,
                body: JSON.stringify({
                    message: 'POST request processed',
                    receivedData: requestBody,
                }),
            };
        default:
            return {
                statusCode: 405,
                body: JSON.stringify({
                    error: 'Method not allowed',
                }),
            };
    }
};

// Lambda function with environment variables
exports.envHandler = async (event) => {
    const environment = process.env.ENVIRONMENT || 'development';
    const region = process.env.AWS_REGION || 'us-east-1';

    return {
        statusCode: 200,
        body: JSON.stringify({
            environment,
            region,
            allEnvVars: Object.keys(process.env).filter(key =>
                key.startsWith('AWS_') || key.startsWith('LAMBDA_')
            ),
        }),
    };
};

# serverless.yml
service: my-serverless-app

frameworkVersion: '3'

provider:
  name: aws
  runtime: nodejs18.x
  region: us-east-1
  stage: dev
  environment:
    NODE_ENV: ${self:custom.currentStage}
    TABLE_NAME: ${self:service}-${self:custom.currentStage}

  iam:
    role:
      statements:
        - Effect: Allow
          Action:
            - dynamodb:Query
            - dynamodb:Scan
            - dynamodb:GetItem
            - dynamodb:PutItem
            - dynamodb:UpdateItem
            - dynamodb:DeleteItem
          Resource:
            - "arn:aws:dynamodb:${self:provider.region}:*:table/${self:provider.environment.TABLE_NAME}"

functions:
  hello:
    handler: handler.hello
    events:
      - http:
          path: hello
          method: get
          cors: true

  users:
    handler: handler.users
    events:
      - http:
          path: users
          method: get
          cors: true
      - http:
          path: users
          method: post
          cors: true

  getUser:
    handler: handler.getUser
    events:
      - http:
          path: users/{id}
          method: get
          cors: true

  processImage:
    handler: handler.processImage
    events:
      - s3:
          bucket: my-image-bucket
          event: s3:ObjectCreated:*
          existing: true
    timeout: 30
    memorySize: 1024

  scheduledTask:
    handler: handler.scheduledTask
    events:
      - schedule:
          rate: rate(5 minutes)
          enabled: true

resources:
  Resources:
    UsersTable:
      Type: AWS::DynamoDB::Table
      Properties:
        TableName: ${self:provider.environment.TABLE_NAME}
        AttributeDefinitions:
          - AttributeName: id
            AttributeType: S
        KeySchema:
          - AttributeName: id
            KeyType: HASH
        BillingMode: PAY_PER_REQUEST
        PointInTimeRecoverySpecification:
          PointInTimeRecoveryEnabled: true
        SSESpecification:
          SSEEnabled: true
        StreamSpecification:
          StreamViewType: NEW_AND_OLD_IMAGES

plugins:
  - serverless-offline
  - serverless-dotenv-plugin
  - serverless-webpack

custom:
  currentStage: ${opt:stage, 'dev'}
  webpack:
    webpackConfig: 'webpack.config.js'
    includeModules: true

  serverless-offline:
    httpPort: 3000
    babelOptions:
      presets: ["env"]

  dotenv:
    path: ./.env
    include:
      - API_KEY
      - DATABASE_URL

package:
  individually: true

  exclude:
    - .git/**
    - .vscode/**
    - node_modules/**
    - "*.log"

// Azure Functions with C#
using System;
using System.IO;
using System.Threading.Tasks;
using Microsoft.AspNetCore.Mvc;
using Microsoft.Azure.WebJobs;
using Microsoft.Azure.WebJobs.Extensions.Http;
using Microsoft.AspNetCore.Http;
using Microsoft.Extensions.Logging;
using Newtonsoft.Json;

namespace MyServerlessApp
{
    public static class HttpFunctions
    {
        [FunctionName("HelloWorld")]
        public static async Task<IActionResult> Run(
            [HttpTrigger(AuthorizationLevel.Function, "get", "post", Route = null)] HttpRequest req,
            ILogger log)
        {
            log.LogInformation("C# HTTP trigger function processed a request.");

            string name = req.Query["name"];

            string requestBody = await new StreamReader(req.Body).ReadToEndAsync();
            dynamic data = JsonConvert.DeserializeObject(requestBody);
            name = name ?? data?.name;

            return name != null
                ? (ActionResult)new OkObjectResult($"Hello, {name}")
                : new BadRequestObjectResult("Please pass a name on the query string or in the request body");
        }
    }

    public static class QueueFunctions
    {
        [FunctionName("ProcessQueueMessage")]
        public static void Run(
            [QueueTrigger("myqueue-items", Connection = "AzureWebJobsStorage")] string myQueueItem,
            ILogger log)
        {
            log.LogInformation($"C# Queue trigger function processed: {myQueueItem}");

            // Process the queue message
            var message = JsonConvert.DeserializeObject<MessageData>(myQueueItem);

            // Business logic here
            log.LogInformation($"Processing message for user: {message.UserId}");
        }
    }

    public static class TimerFunctions
    {
        [FunctionName("DailyCleanup")]
        public static void Run(
            [TimerTrigger("0 0 3 * * *")] TimerInfo myTimer,
            ILogger log)
        {
            log.LogInformation($"Daily cleanup function executed at: {DateTime.Now}");

            if (myTimer.IsPastDue)
            {
                log.LogInformation("Timer is running late!");
            }

            // Cleanup logic here
            PerformDailyCleanup();
        }

        private static void PerformDailyCleanup()
        {
            // Implement cleanup logic
            // e.g., delete old files, clean up database, etc.
        }
    }

    public static class BlobFunctions
    {
        [FunctionName("ProcessImageUpload")]
        public static void Run(
            [BlobTrigger("images/{name}", Connection = "AzureWebJobsStorage")] Stream myBlob,
            string name,
            ILogger log)
        {
            log.LogInformation($"C# Blob trigger function processed blob\n Name:{name} \n Size: {myBlob.Length} Bytes");

            // Process uploaded image
            ProcessImage(myBlob, name);
        }

        private static void ProcessImage(Stream imageStream, string fileName)
        {
            // Implement image processing logic
            // e.g., resize, add watermark, generate thumbnails
        }
    }

    public static class CosmosDBFunctions
    {
        [FunctionName("CreateUser")]
        public static async Task<IActionResult> CreateUser(
            [HttpTrigger(AuthorizationLevel.Function, "post", Route = "users")] HttpRequest req,
            [CosmosDB(
                databaseName: "MyDatabase",
                collectionName: "Users",
                ConnectionStringSetting = "CosmosDBConnection")] IAsyncCollector<User> usersOut,
            ILogger log)
        {
            log.LogInformation("Creating a new user");

            string requestBody = await new StreamReader(req.Body).ReadToEndAsync();
            var user = JsonConvert.DeserializeObject<User>(requestBody);

            user.Id = Guid.NewGuid().ToString();
            user.CreatedAt = DateTime.UtcNow;

            await usersOut.AddAsync(user);

            return new CreatedResult($"/users/{user.Id}", user);
        }

        [FunctionName("GetUser")]
        public static IActionResult GetUser(
            [HttpTrigger(AuthorizationLevel.Function, "get", Route = "users/{id}")] HttpRequest req,
            [CosmosDB(
                databaseName: "MyDatabase",
                collectionName: "Users",
                Id = "{id}",
                PartitionKey = "{id}",
                ConnectionStringSetting = "CosmosDBConnection")] User user,
            ILogger log)
        {
            log.LogInformation($"Getting user with id: {req.RouteValues["id"]}");

            if (user == null)
            {
                return new NotFoundResult();
            }

            return new OkObjectResult(user);
        }
    }

    // Data models
    public class MessageData
    {
        public string UserId { get; set; }
        public string Message { get; set; }
        public DateTime Timestamp { get; set; }
    }

    public class User
    {
        [JsonProperty("id")]
        public string Id { get; set; }

        [JsonProperty("name")]
        public string Name { get; set; }

        [JsonProperty("email")]
        public string Email { get; set; }

        [JsonProperty("createdAt")]
        public DateTime CreatedAt { get; set; }
    }
}

# Google Cloud Functions with Python
import functions_framework
from flask import jsonify, request
import json
import logging
import os
from datetime import datetime
from google.cloud import storage
from google.cloud import datastore

# Configure logging
logging.basicConfig(level=logging.INFO)

@functions_framework.http
def hello_world(request):
    """HTTP Cloud Function that returns a JSON greeting."""

    request_json = request.get_json(silent=True)
    request_args = request.args

    if request_json and 'name' in request_json:
        name = request_json['name']
    elif request_args and 'name' in request_args:
        name = request_args['name']
    else:
        name = 'World'

    response_data = {
        'message': f'Hello, {name}!',
        'timestamp': datetime.utcnow().isoformat(),
        'method': request.method,
        'headers': dict(request.headers)
    }

    return jsonify(response_data), 200

@functions_framework.http
def process_data(request):
    """HTTP Cloud Function that processes incoming data."""

    if request.method != 'POST':
        return jsonify({'error': 'Method not allowed'}), 405

    try:
        data = request.get_json()

        if not data:
            return jsonify({'error': 'No data provided'}), 400

        # Validate required fields
        if 'user_id' not in data or 'event_type' not in data:
            return jsonify({'error': 'Missing required fields'}), 400

        # Process the data
        processed_data = {
            'user_id': data['user_id'],
            'event_type': data['event_type'],
            'processed_at': datetime.utcnow().isoformat(),
            'metadata': {
                'source_ip': request.remote_addr,
                'user_agent': request.headers.get('User-Agent', ''),
            }
        }

        # Add additional processing logic here
        if data.get('payload'):
            processed_data['payload_size'] = len(json.dumps(data['payload']))

        # Save to Datastore (optional)
        save_to_datastore(processed_data)

        return jsonify({
            'status': 'success',
            'processed_data': processed_data
        }), 200

    except Exception as e:
        logging.error(f"Error processing data: {str(e)}")
        return jsonify({'error': 'Internal server error'}), 500

@functions_framework.cloud_event
def process_pubsub_message(cloud_event):
    """Background Cloud Function to handle Pub/Sub messages."""

    try:
        # Extract message data
        message_data = cloud_event.data.get('message', {})

        if 'data' in message_data:
            # Decode base64 message
            import base64
            decoded_message = base64.b64decode(message_data['data']).decode('utf-8')
            message_json = json.loads(decoded_message)
        else:
            message_json = message_data

        logging.info(f"Received Pub/Sub message: {message_json}")

        # Process the message
        result = process_message(message_json)

        logging.info(f"Message processed successfully: {result}")

    except Exception as e:
        logging.error(f"Error processing Pub/Sub message: {str(e)}")
        raise

@functions_framework.cloud_event
def process_gcs_event(cloud_event):
    """Background Cloud Function to handle GCS object changes."""

    try:
        # Extract bucket and file information
        bucket = cloud_event.data.get('bucket')
        name = cloud_event.data.get('name')
        generation = cloud_event.data.get('generation')
        eventType = cloud_event.type

        logging.info(f"GCS Event: {eventType} for gs://{bucket}/{name} (generation: {generation})")

        if eventType == 'google.storage.object.finalize':
            # Process new file
            process_uploaded_file(bucket, name)
        elif eventType == 'google.storage.object.delete':
            # Handle file deletion
            logging.info(f"File deleted: gs://{bucket}/{name}")

    except Exception as e:
        logging.error(f"Error processing GCS event: {str(e)}")
        raise

def save_to_datastore(data):
    """Save data to Google Cloud Datastore."""
    try:
        client = datastore.Client()
        kind = 'ProcessedEvent'

        # Create a new entity
        key = client.key(kind)
        entity = datastore.Entity(key=key)

        # Set entity properties
        entity.update(data)

        # Save the entity
        client.put(entity)

        logging.info(f"Data saved to Datastore with key: {entity.key}")

    except Exception as e:
        logging.error(f"Error saving to Datastore: {str(e)}")

def process_message(message):
    """Process incoming Pub/Sub message."""
    # Add your business logic here
    return {
        'processed': True,
        'message_type': message.get('type', 'unknown'),
        'timestamp': datetime.utcnow().isoformat()
    }

def process_uploaded_file(bucket_name, file_name):
    """Process uploaded file in GCS."""
    try:
        client = storage.Client()
        bucket = client.bucket(bucket_name)
        blob = bucket.blob(file_name)

        # Get file metadata
        blob.reload()
        file_size = blob.size
        content_type = blob.content_type

        logging.info(f"Processing file: {file_name} ({file_size} bytes, {content_type})")

        # Add file processing logic here
        if content_type and content_type.startswith('image/'):
            # Process image
            process_image_file(bucket_name, file_name)
        elif content_type and 'csv' in content_type:
            # Process CSV file
            process_csv_file(bucket_name, file_name)

    except Exception as e:
        logging.error(f"Error processing uploaded file: {str(e)}")

def process_image_file(bucket_name, file_name):
    """Process uploaded image file."""
    # Add image processing logic
    logging.info(f"Processing image: {file_name}")
    # e.g., resize, add watermark, generate thumbnails

def process_csv_file(bucket_name, file_name):
    """Process uploaded CSV file."""
    # Add CSV processing logic
    logging.info(f"Processing CSV: {file_name}")
    # e.g., parse data, save to database

# Environment configuration helper
def get_config():
    """Get configuration from environment variables."""
    return {
        'project_id': os.getenv('GCP_PROJECT'),
        'environment': os.getenv('ENVIRONMENT', 'development'),
        'log_level': os.getenv('LOG_LEVEL', 'INFO')
    }

# AWS API Gateway with Lambda Integration
AWSTemplateFormatVersion: '2010-09-09'
Transform: AWS::Serverless-2016-10-31
Description: Serverless API with API Gateway

Globals:
  Function:
    Timeout: 30
    MemorySize: 256
    Runtime: python3.9

Parameters:
  Stage:
    Type: String
    Default: dev
    AllowedValues:
      - dev
      - staging
      - prod
    Description: Deployment stage

Resources:
  # API Gateway REST API
  ApiGatewayRestApi:
    Type: AWS::Serverless::Api
    Properties:
      Name: !Sub '${AWS::StackName}-api-${Stage}'
      StageName: !Ref Stage
      DefinitionUri: s3://api-definition-bucket/openapi.yaml
      Variables:
        LambdaFunctionName: !Ref MyApiFunction
      Cors:
        AllowMethods: "'GET,POST,PUT,DELETE,OPTIONS'"
        AllowHeaders: "'Content-Type,X-Amz-Date,Authorization,X-Api-Key,X-Amz-Security-Token'"
        AllowOrigin: "'*'"

  # Lambda Functions
  MyApiFunction:
    Type: AWS::Serverless::Function
    Properties:
      FunctionName: !Sub '${AWS::StackName}-api-${Stage}'
      CodeUri: src/
      Handler: app.lambda_handler
      Runtime: python3.9
      Environment:
        Variables:
          TABLE_NAME: !Ref DataTable
          REGION: !Ref AWS::Region
      Policies:
        - DynamoDBCrudPolicy:
            TableName: !Ref DataTable
      Events:
        ApiEvents:
          Type: Api
          Properties:
            RestApiId: !Ref ApiGatewayRestApi
            Path: /{proxy+}
            Method: ANY

  # DynamoDB Table
  DataTable:
    Type: AWS::DynamoDB::Table
    Properties:
      TableName: !Sub '${AWS::StackName}-data-${Stage}'
      AttributeDefinitions:
        - AttributeName: id
          AttributeType: S
        - AttributeName: type
          AttributeType: S
      KeySchema:
        - AttributeName: id
          KeyType: HASH
        - AttributeName: type
          KeyType: RANGE
      BillingMode: PAY_PER_REQUEST
      StreamSpecification:
        StreamViewType: NEW_AND_OLD_IMAGES
      PointInTimeRecoverySpecification:
        PointInTimeRecoveryEnabled: true

  # Lambda Authorizer
  ApiAuthorizer:
    Type: AWS::Serverless::Function
    Properties:
      FunctionName: !Sub '${AWS::StackName}-authorizer-${Stage}'
      CodeUri: authorizer/
      Handler: authorizer.lambda_handler
      Runtime: python3.9
      Environment:
        Variables:
          JWT_SECRET: !Ref JwtSecret
      Policies:
        - Statement:
            Effect: Allow
            Action:
              - secretsmanager:GetSecretValue
            Resource: !Sub arn:aws:secretsmanager:${AWS::Region}:${AWS::AccountId}:secret:${JwtSecret}*

  # Custom Domain
  ApiDomainName:
    Type: AWS::ApiGateway::DomainName
    Properties:
      DomainName: !Sub 'api-${Stage}.example.com'
      EndpointConfiguration:
        Types:
          - REGIONAL
      RegionalCertificateArn: !Ref SslCertificate
      SecurityPolicy: TLS_1_2

  # API Gateway Base Path Mapping
  BasePathMapping:
    Type: AWS::ApiGateway::BasePathMapping
    Properties:
      DomainName: !Ref ApiDomainName
      RestApiId: !Ref ApiGatewayRestApi
      Stage: !Ref Stage

  # CloudWatch Log Group
  ApiLogGroup:
    Type: AWS::Logs::LogGroup
    Properties:
      LogGroupName: !Sub '/aws/lambda/${MyApiFunction}'
      RetentionInDays: 30

# Output values
Outputs:
  ApiEndpoint:
    Description: API Gateway endpoint URL
    Value: !Sub 'https://${ApiGatewayRestApi}.execute-api.${AWS::Region}.amazonaws.com/${Stage}'

  ApiFunction:
    Description: Lambda function ARN
    Value: !GetAtt MyApiFunction.Arn

  TableName:
    Description: DynamoDB table name
    Value: !Ref DataTable

# OpenAPI Specification for API Gateway
# openapi.yaml
openapi: 3.0.0
info:
  title: Serverless API
  version: 1.0.0
  description: Serverless API with Lambda backend

servers:
  - url: https://{domain}/prod
    variables:
      domain:
        default: api.example.com

paths:
  /health:
    get:
      summary: Health check endpoint
      responses:
        '200':
          description: API is healthy
          content:
            application/json:
              schema:
                type: object
                properties:
                  status:
                    type: string
                  timestamp:
                    type: string

  /users:
    get:
      summary: Get all users
      security:
        - ApiKeyAuth: []
      responses:
        '200':
          description: List of users
    post:
      summary: Create new user
      security:
        - ApiKeyAuth: []
      requestBody:
        required: true
        content:
          application/json:
            schema:
              $ref: '#/components/schemas/User'
      responses:
        '201':
          description: User created
        '400':
          description: Invalid input

  /users/{userId}:
    get:
      summary: Get user by ID
      security:
        - ApiKeyAuth: []
      parameters:
        - name: userId
          in: path
          required: true
          schema:
            type: string
      responses:
        '200':
          description: User details
        '404':
          description: User not found
    put:
      summary: Update user
      security:
        - ApiKeyAuth: []
      parameters:
        - name: userId
          in: path
          required: true
          schema:
            type: string
      requestBody:
        required: true
        content:
          application/json:
            schema:
              $ref: '#/components/schemas/User'
      responses:
        '200':
          description: User updated
        '404':
          description: User not found
    delete:
      summary: Delete user
      security:
        - ApiKeyAuth: []
      parameters:
        - name: userId
          in: path
          required: true
          schema:
            type: string
      responses:
        '204':
          description: User deleted
        '404':
          description: User not found

components:
  securitySchemes:
    ApiKeyAuth:
      type: apiKey
      in: header
      name: X-API-Key
    BearerAuth:
      type: http
      scheme: bearer
      bearerFormat: JWT

  schemas:
    User:
      type: object
      required:
        - name
        - email
      properties:
        id:
          type: string
          readOnly: true
        name:
          type: string
        email:
          type: string
          format: email
        role:
          type: string
          enum: [user, admin]
          default: user