aws-api-gateway

# AWS API Gateway Amazon API Gateway is a fully managed service for creating, publishing, and securing APIs at any scale. Supports REST APIs, HTTP APIs, and WebSocket APIs. ## Table of Contents - [Core Concepts](#core-concepts) - [Common Patterns](#common-patterns) - [CLI Reference](#cli-reference) - [Best Practices](#best-practices) - [Troubleshooting](#troubleshooting) - [References](#references) ## Core Concepts ### API Types | Type | Description | Use Case | |------|-------------|----------| | **HTTP API** | Low-latency, cost-effective | Simple APIs, Lambda proxy | | **REST API** | Full-featured, more control | Complex APIs, transformation | | **WebSocket API** | Bidirectional communication | Real-time apps, chat | ### Key Components - **Resources**: URL paths (/users, /orders/{id}) - **Methods**: HTTP verbs (GET, POST, PUT, DELETE) - **Integrations**: Backend connections (Lambda, HTTP, AWS services) - **Stages**: Deployment environments (dev, prod) ### Integration Types | Type | Description | |------|-------------| | **Lambda Proxy** | Pass-through to Lambda (recommended) | | **Lambda Custom** | Transform request/response | | **HTTP Proxy** | Pass-through to HTTP endpoint | | **AWS Service** | Direct integration with AWS services | | **Mock** | Return static response | ## Common Patterns ### Create HTTP API with Lambda **AWS CLI:** ```bash # Create HTTP API aws apigatewayv2 create-api \ --name my-api \ --protocol-type HTTP \ --target arn:aws:lambda:us-east-1:123456789012:function:MyFunction # Get API endpoint aws apigatewayv2 get-api --api-id abc123 --query 'ApiEndpoint' ``` **SAM Template:** ```yaml AWSTemplateFormatVersion: '2010-09-09' Transform: AWS::Serverless-2016-10-31 Resources: MyApi: Type: AWS::Serverless::HttpApi Properties: StageName: prod MyFunction: Type: AWS::Serverless::Function Properties: Handler: app.handler Runtime: python3.12 Events: ApiEvent: Type: HttpApi Properties: ApiId: !Ref MyApi Path: /items Method: GET ``` ### Create REST API with Lambda Proxy ```bash # Create REST API aws apigateway create-rest-api \ --name my-rest-api \ --endpoint-configuration types=REGIONAL API_ID=abc123 # Get root resource ID ROOT_ID=$(aws apigateway get-resources --rest-api-id $API_ID --query 'items[0].id' --output text) # Create resource aws apigateway create-resource \ --rest-api-id $API_ID \ --parent-id $ROOT_ID \ --path-part items RESOURCE_ID=xyz789 # Create method aws apigateway put-method \ --rest-api-id $API_ID \ --resource-id $RESOURCE_ID \ --http-method GET \ --authorization-type NONE # Create Lambda integration aws apigateway put-integration \ --rest-api-id $API_ID \ --resource-id $RESOURCE_ID \ --http-method GET \ --type AWS_PROXY \ --integration-http-method POST \ --uri arn:aws:apigateway:us-east-1:lambda:path/2015-03-31/functions/arn:aws:lambda:us-east-1:123456789012:function:MyFunction/invocations # Deploy to stage aws apigateway create-deployment \ --rest-api-id $API_ID \ --stage-name prod ``` ### Lambda Handler for API Gateway ```python import json def handler(event, context): http_method = event.get('requestContext', {}).get('http', {}).get('method') path = event.get('rawPath', '') query_params = event.get('queryStringParameters', {}) body = event.get('body', '') if body and event.get('isBase64Encoded'): import base64 body = base64.b64decode(body).decode('utf-8') response_body = {'message': 'Success', 'path': path} return { 'statusCode': 200, 'headers': { 'Content-Type': 'application/json' }, 'body': json.dumps(response_body) } ``` ### Configure CORS **HTTP API:** ```bash aws apigatewayv2 update-api \ --api-id abc123 \ --cors-configuration '{ "AllowOrigins": ["https://example.com"], "AllowMethods": ["GET", "POST", "PUT", "DELETE"], "AllowHeaders": ["Content-Type", "Authorization"], "MaxAge": 86400 }' ``` ### JWT Authorization (HTTP API) ```bash aws apigatewayv2 create-authorizer \ --api-id abc123 \ --name jwt-authorizer \ --authorizer-type JWT \ --identity-source '$request.header.Authorization' \ --jwt-configuration '{ "Issuer": "https://cognito-idp.us-east-1.amazonaws.com/us-east-1_abc123", "Audience": ["client-id"] }' ``` ## CLI Reference ### HTTP API (apigatewayv2) | Command | Description | |---------|-------------| | `aws apigatewayv2 create-api` | Create API | | `aws apigatewayv2 get-apis` | List APIs | | `aws apigatewayv2 create-route` | Create route | | `aws apigatewayv2 create-integration` | Create integration | | `aws apigatewayv2 create-stage` | Create stage | | `aws apigatewayv2 create-authorizer` | Create authorizer | ### REST API (apigateway) | Command | Description | |---------|-------------| | `aws apigateway create-rest-api` | Create API | | `aws apigateway get-rest-apis` | List APIs | | `aws apigateway create-resource` | Create resource | | `aws apigateway put-method` | Create method | | `aws apigateway put-integration` | Create integration | | `aws apigateway create-deployment` | Deploy API | ## Best Practices ### Performance - **Use HTTP APIs** for simple use cases (70% cheaper, lower latency) - **Enable caching** for REST APIs - **Use regional endpoints** unless global distribution needed ### Security - **Use authorization** on all endpoints - **Enable WAF** for REST APIs - **Enable access logging** - **Use HTTPS only** ### Reliability - **Set up throttling** to protect backends - **Configure timeout** appropriately - **Monitor with CloudWatch** ## Troubleshooting ### 403 Forbidden **Causes:** - Missing authorization - Invalid API key - WAF blocking - Resource policy denying ### 502 Bad Gateway **Causes:** - Lambda error - Integration timeout - Invalid response format **Lambda response format:** ```python # Correct format return { 'statusCode': 200, 'headers': {'Content-Type': 'application/json'}, 'body': json.dumps({'message': 'success'}) } # Wrong - missing statusCode return {'message': 'success'} ``` ### 504 Gateway Timeout **Causes:** - Backend timeout (Lambda max 29 seconds for REST API) - Integration timeout too short **Solutions:** - Increase Lambda timeout - Use async processing for long operations ### CORS Errors **Debug:** - Check OPTIONS method exists - Verify headers in response - Check origin matches allowed origins ## References - [API Gateway Developer Guide](https://docs.aws.amazon.com/apigateway/latest/developerguide/) - [API Gateway REST API Reference](https://docs.aws.amazon.com/apigateway/latest/api/) - [API Gateway CLI Reference](https://docs.aws.amazon.com/cli/latest/reference/apigateway/) - [boto3 API Gateway](https://boto3.amazonaws.com/v1/documentation/api/latest/reference/services/apigateway.html)