Serverless Framework — Infrastructure as Code for Serverless

# serverless.yml
service: user-api

provider:
  name: aws
  runtime: python3.9
  region: us-east-1
  stage: ${opt:stage, 'dev'}
  environment:
    TABLE_NAME: ${self:service}-${self:provider.stage}-users
  iamRoleStatements:
    - Effect: Allow
      Action:
        - dynamodb:GetItem
        - dynamodb:PutItem
        - dynamodb:Query
      Resource: !GetAtt UsersTable.Arn

functions:
  createUser:
    handler: handlers/users.create
    events:
      - httpApi:
          method: POST
          path: /users
  getUser:
    handler: handlers/users.get
    events:
      - httpApi:
          method: GET
          path: /users/{id}

resources:
  Resources:
    UsersTable:
      Type: AWS::DynamoDB::Table
      Properties:
        TableName: ${self:service}-${self:provider.stage}-users
        BillingMode: PAY_PER_REQUEST
        AttributeDefinitions:
          - AttributeName: id
            AttributeType: S
        KeySchema:
          - AttributeName: id
            KeyType: HASH

# handlers/users.py
# Lambda handlers for user CRUD

import json

def create(event, context):
    body = json.loads(event.get("body", "{}"))
    user = {"id": body.get("email"), "name": body.get("name"), "email": body.get("email")}
    print(f"Created user: {user['email']}")
    return {"statusCode": 201, "body": json.dumps(user)}

def get(event, context):
    user_id = event.get("pathParameters", {}).get("id")
    user = {"id": user_id, "name": "Alice", "email": "alice@example.com"}
    return {"statusCode": 200, "body": json.dumps(user)}

# Test
test_create = {"body": json.dumps({"name": "Alice", "email": "alice@example.com"})}
print(create(test_create, None)["body"])
test_get = {"pathParameters": {"id": "alice@example.com"}}
print(get(test_get, None)["body"])

# plugins.py
# Common Serverless Framework plugins

def list_popular_plugins():
    plugins = [
        ("serverless-offline", "Run Lambda and API Gateway locally"),
        ("serverless-webpack", "Bundle Node.js functions with webpack"),
        ("serverless-python-requirements", "Bundle Python dependencies"),
        ("serverless-prune-plugin", "Remove old function versions"),
        ("serverless-dotenv-plugin", "Load .env files for local development"),
        ("serverless-step-functions", "Define Step Functions in serverless.yml"),
        ("serverless-iam-roles-per-function", "Per-function IAM roles"),
    ]
    
    print(f"{'Plugin':35s} {'Description':50s}")
    print("-" * 85)
    for name, desc in plugins:
        print(f"{name:35s} {desc:50s}")

list_popular_plugins()

# stages.py
# Multi-environment configuration

def get_stage_config(stage):
    configs = {
        "dev": {
            "table_name": "users-dev",
            "log_level": "DEBUG",
            "api_url": "https://api.dev.example.com"
        },
        "staging": {
            "table_name": "users-staging",
            "log_level": "INFO",
            "api_url": "https://api.staging.example.com"
        },
        "prod": {
            "table_name": "users-prod",
            "log_level": "WARNING",
            "api_url": "https://api.example.com"
        }
    }
    return configs.get(stage, configs["dev"])

def deploy_stage(stage):
    config = get_stage_config(stage)
    print(f"Deploying to {stage}...")
    for key, value in config.items():
        print(f"  {key}: {value}")
    print(f"  sls deploy --stage {stage}")
    print(f"  Stack: user-api-{stage}")
    print(f"  API URL: {config['api_url']}")

deploy_stage("dev")
print()
deploy_stage("prod")

import json
import hashlib
import time

store = {}

def shorten(event, context):
    body = json.loads(event.get("body", "{}"))
    url = body.get("url")
    if not url:
        return {"statusCode": 400, "body": json.dumps({"error": "Missing url"})}
    code = hashlib.md5(url.encode()).hexdigest()[:8]
    store[code] = url
    print(f"Shortened {url} -> {code}")
    return {"statusCode": 201, "body": json.dumps({"shortCode": code, "url": f"https://short.ly/{code}"})}

def redirect(event, context):
    code = event.get("pathParameters", {}).get("code")
    url = store.get(code)
    if not url:
        return {"statusCode": 404, "body": json.dumps({"error": "Not found"})}
    return {"statusCode": 301, "headers": {"Location": url}, "body": ""}

print(shorten({"body": json.dumps({"url": "https://example.com"})}, None)["body"])