API Gateway

Question 1

What are the three main API Gateway Endpoint Types

Answer 1

Edge Optimized (default)

• Requests are routed through the CloudFront Edge locations
• API Gateway still only lives in one region

Regional

• For clients within the same region
• Could manually combine with CloudFront

Private

• Can only be accessed from you VPC using an interface VPC endpoint (ENI)
• Use resource polict to fedine access

Question 2

What is an API deployment?

Answer 2

• A point-in-time snapshot of your API Gateway API.
• To be available for clients to use, the deployment must be associated with one or more API stages

Question 3

What is an API stage?

Answer 3

A logical reference to a lifecycle state of your API (for example, ‘dev’, ‘prod’, ‘beta’, ‘v2’). API stages are identified by API ID and stage name.

Question 4

What are Canary deployments on API Gateway?

Answer 4

• It the API Gateway verson of a blue/green deployment with AWS lambda.
• Choose the % of traffic the canary channel recieves

Question 5

Why use an API cache? When would you not use one?

Answer 5

• Caching reduces the # of calls made to the backend.
• They are defined per stage
• Can be encrypted
• They are expensive so may not make sense in the dev environment.

Question 6

How are API Gateway Caches invalidated?

Answer 6

• Clients can invalidate the cache with header: Cache-Control: max-age=0 (requires proper IAM authorization)
• If you do not impose an InvalidateCache policy (or choose the Require authorization check box in the console), any client can invalidate the API cache = bad.

Question 7

What is the default TTL in the API Gateway Cache?

Answer 7

300 seconds (5 mintues)

min = 0s, max = 3600s

Question 8

What are the 4 Integration Types for API Gateways?

Answer 8

• MOCK
• HTTP
• AWS_PROXY (Lambda Proxy)
• HTTP_PROXY

Question 9

Describe API Gateway Integration Type MOCK

Answer 9

• API Gateway returns a response without sending the request to the backend.
• Good for development

Question 10

Describe API Gateway Integration Type HTTP / AWS (Lambda and AWS Services)

Answer 10

• You must configure both the integration request and integration response
• Setup data mapping using mapping templates for the request and response

Question 11

Describe API Gateway AWS_PROXY Integration Type

Answer 11

• Incoming request from the client is the input to Lambda
• The function is responsible for the logic of request / response
• No mapping template, headers, query string parameters etc. are passed as arguments.

Question 12

Describe API Gateway HTTP_PROXY Integration Type

Answer 12

• No Mapping template
• The HTTP request is passed to the backend
• The HTTP repsonse from the backend is forwarded by API Gateway

Question 13

What are API Gateway Mapping Templates?

Answer 13

• Mapping templates are data transformation tools that can be used to modify request / responses.
  
  • Rename / Modify query string params
  • Modify body content
  • Add Headers
  • Uses Velocity Template Language (VTL): for loop, if etc …
  • Filter output results (remove unnecessary data)

Question 14

In API Gateway, what is an integration?

Answer 14

• Integration connects a route to backend resources.
• Each API type has its own integration types.

Question 15

What are the 4 API Gateway types? Summarize Each.

Answer 15

HTTP API

• Low latency and cost effective. Integrates in with OAuth and OIDC.
• Works with Lambda and HTTP backends
• No useage plan

REST API

• Have more control - main use of API Gateway
• Works with Lambda, HTTP, AWS Services

Web Socket API

• Best used for real-time data apps like chat applications or dashboards.Think 2-way applications.
• Requests get routed to a specific routing expression.
• Works with Lambda, HTTP, and AWS Sweater

REST API (Private)

• Accessible only from VPC

Question 16

What is the correct order of steps to configure a usage plan/api keys in API Gateway?

Answer 16

1. Create one or more APIs, configure methods to require an API key, and deploy the API to stages.
2. Generate or import API keys to distribute to application developers (your customers) who will be using your API.
3. Create the usage plan with the desired throttle and quota limits.
4. Associate API stages and API keys with the useage plan.
5. Callers of the API must supply an assigned API key in the x-api-key header in requests to the API.

Question 17

API Gateway - What is a usage plan?

Answer 17

• Usage plans help you meter API usage.
• You can enforce throttling and quota limits on each API key.

Question 18

API Gateway - what are throttling limits?

Answer 18

Throttling limits define the maximum number of requests per second available to each key.

Question 19

API Gateway - What are quota limits?

Answer 19

Quota limits define the number of requests each API key is allowed to make over a period of time.

Question 20

What is the maximum amount of time for a request in API Gateway?

Answer 20

29 seconds.

If the request lasts longer then 29 seconds then it will return a timeout error.

Question 21

What 2 API methods can hep you evaluate the efficency of your API Gateway cache?

Answer 21

• CacheHitCount
• CacheMissCount

Question 22

What metric allows you to monitor the time it takes for an API Gateway to relay a request to the backend and how long it takes to get a response from the backend?

Answer 22

IntegrationLatency

Question 23

What API metric allows you to measure the time between when API Gateway recieves a request from a client and how long it takes the client to recieve a response for the API Gateway?

Answer 23

Latency.

This includes the IntegrationLatencyTime as well as the overhead of the API Gateway itself.

Question 24

What is the default throttling measure across all of you API Gateways?

Answer 24

10,000 requests per second

This is a soft limit that can be increased on request

Question 25

What error code will you recieve if you have reached throttling limits in API Gateway?

Answer 25

429

Question 27

What are the 3 main ways you can secure you API Gateway?

Answer 27

***I******AM / Resource Policy*** - Best if you're already managing users/groups and/or need cross account access. Uses Sigv4 ***Custom Authorizer*** - for when youre uing a 3rd party like OAuth / OIDC ***AWS Cognito***

Question 28

What is AWS API Gateway?

Answer 28

* Amazon API Gateway is a fully managed service that makes it easy for developers to create, publish, maintain, monitor, and secure APIs at any scale. * APIs act as the front door for applications to access data, business logic, or functionality from your backend services.