Appications

Simple Queue Service (SQS)

SQS standard (offers as the default queue type)

nearly-unlimited number of transactions per second
message is delivered at least once (more than one copy of a message might be delivered out of order)

FIFO queue

message is delivered once (remain until a consumer processes and deletes it)
300 transactions per second

Tips

SQS is pull based, not pushed based
messages are 256KB in size
messages can be kept in the queue from 1 minute to 14 days, the default retention period is 4 days
VisibilityTimeout: the amount of time that the message is invisible in the SQS queue after a reader picks up that message. Provided the job is processed before the visibility time out expires, the message will then be deleted from the queue. If the job is not processed within that time, the message will become visible again and another reader will process it. This could result in the same message begin deliverd twice
- Visibility timeout maximum is 12 hours
DelaySeconds: when a new message is added to the SQS queue, it will be hidden from consumer instances for a fixed period
SQS long polling is a way to retrieve messages from your Amazon SQS queues. While the regular short polling returns messages immediately (even if the message queue being polled is empty), long polling doesn't return a response until a message arrives in the message queue, or the long poll times out ⇒ save money
- WaitTimeSeconds + ReceiveMessageWaitTimeSeconds: when the consumer instance polls for new work, the SQS service will allow it to wait a certain time for one or more message to be available before closing the connection (if is 0 ⇒ short polling)

Simple Workflow (SWF)

SQS vs SWF

SWF

retention period 1 year
task-oriented API
task is assigned only once and is never duplicated
keep track all the task and event

SQS

14 days
message-oriented API
need to handle duplicated messages and ensure that a message is processed only once
need to implement your own application-level tracking, especially if you use multiple queues

SWF Actors

workflow starter - initiate workflow
decider - control the flow of activity tasks
activity worker - carry out the activity tasks

Simple Notification Service (SNS)

SNS Benefits

push-based delivery (not pull based)
simple APIs, easy integration
flexible message delivery over multiple transpot protocols
inexpensive, pay-as-you-go
web-based AWS Management Console offers the simplicity of a point-and-click interface

Elastic Transcoder

Media Transcoder in the cloud
Convert media files from their original source format in to different formats that will play on smartphones, tablets, PCs
provide transcoding presets for popular output format
pay based on the minutes that you transcode and th resolution at which you transcode

API Gateway

API Gateway is at a high level
API Gateway has caching capabilities to increase performance
API Gateway is low cost and scales automatically
can throttle API Gateway to prevent attacks
can log results to CloudWatch
enable CORS on API Gateway to use Javascipt communicate with multiple domains
CORS is enforced by the client
See more: CORS - Cross Same Origin Policy

Kinesis

A platform on AWS to send your streaming data to

Kinesis Streams

data is persistance in 24 hour (up to 7days)
consist of shards:
- 5 transactions/second for reads, maximum total data read: 2MB/second
- 1000 records/second for writes, maximum total data write: 1MB/second (including partition keys)
- total capacity of the stream is the sum of the capacities of itss shards

Kinesis Firehose

no persistent storage (data has to be processed when it come in using lambda)

Kinesis Analytics

analyze the data on the fly inside either service

Cognito - Web identity Federation

let your users access to AWS resources after they have authenticated with a identity provider like Amazon, Facebook, Google
sign up and sign in to your apps
access for guest users
act as an Identity Broker between your app and Web ID provider
synchronize user data for multiple devices
recommend for all mobile app AWS services

User Pools

for authentication purpose
manage sign-up sign-in functionality for mobile and web app
can sign-in directly (use email, password) or use Facebook, Amazon, Google

Identity Pools

for authorization purpose
provide temporary AWS credentials to access AWS services like S3 or DynamoDB

Key Management Service (KMS)

Compare with other encrypt service