Step functions & APPSYNC

Question 1

Step function overview
what is it used to orchestrate
features of conditions
max duration

Answer 1

Build server less workflow to orchestrate lambda functions

FLOW as JSON STATE MACHINE

Features:
Sequence
parallel
conditions
timeouts, error handling

Also integrate ec2, ecs, on premise, api gateway

MAX duration 1 year

possible to have human approval

use case example:
order fulfillment
data processing
web apps
any workflow

Question 2

Step function
Error handling

error types
default error trigger
resolution
best practice

Answer 2

Errors:

1. state machine definition issue, condition doesn’t match possible outcomes to be handled
2. task failure, lambda function messed up
3. transient issues, network went down

DEFAULT: error causes step function execution to fail entirely

resolution:

1. retry failure 
RETRY:
INTERVALSECONDS: time between
MAXATTEMPTS: max times to retry
BACKOFFRATE: how to space retries

2. Moving on
   Catch: ERROREQUALS, NEXT: if error then move to next step

*best practice, put data in error to see what happened to debug

Question 3

Step function

Standard vs express

Answer 3

Standard: : LONGER, EXPENSIVE
Max duration 1 year
start rate: 2000 starts per second

Express : Cheaper, SHORTER
Max duration 5 minutes
start rate: 100,000 start per second

Question 4

APPSYNC overview
two main functions
how to start

Answer 4

Starts with uploading GraphQL schema

1. use as GraphQL managed service
   Appsync: Managed service that uses GRAPHQL
   GraphQL: Makes it easy for apps to get specific data that it needs
   -combine data from one or more source
   -NoSQL data stores, relational DB, HTTP API
   -Integrate with DynamoDB, aurora, elasticsearch
   -custom source via AWS Lambda
2. Retrieve data : REALTIME WITH WEBSOCKET OR MQTT ON WEBSOCKET
   - for mobile apps local data access and data sync
   - cognito sync replacement

Question 5

APPSYNC process

schema
query
response in?

Answer 5

1. Upload GraphQL Schema to APPSYNC
   format of data
2. Client will send a GraphQL Query to Appsync
   data to be requested matching format
3. Appsync will take the client request and run a resolver and find the data in dynamoDB
4. APPSYNC returns query as
   GRAPHQL response in JSON

Question 6

APPSYNC process
items to use it

requests from
appsync contains
data sources
integration for monitoring

Answer 6

1.Appsync can receive request from
web apps
mobile apps
real time dashboard
offline sync

2. Appsync contains
   GraphQL schema (what requests will be formatted as)
   RESOLVERS: Where to get data from

3. data sources
dynamodb
aurora
elasticsearch
lambda can process extra
HTTP-- PUBLIC HTTP API

4.APPSYNC can integrate with
Cloudwatch Logs for logging
Cloudwatch metrics also

Question 7

Appsync security

four methods to authorize apps to interact with AWS APPSYN GRAPHQL API

Answer 7

four methods to authorize apps to interact with AWS APPSYN GRAPHQL API

1. API_KEY
   - generate just like api gateway, give to users
2. AWS_IAM:
   - users, roles, cross account acess
3. OPENID_CONNECT:
   - integration with third party provider and JSON web token
4. AMAZON_COGNITO_USER_POOLS
   - integrate with users already in cognito, also can use social logins

For custom domain and HTTPS:
Use cloud front in front of APPSYNC