Amazon Simple Queue Service (SQS) is a fully managed message queuing service that enables you to decouple and scale microservices, distributed systems, and serverless applications.
- Message queue service
- Retention 1min to 14 days (default: 4 days)
- SQS is pull based, not push based. Supports short and long polling
- Messages size is up to 256KB
- Visibility timeout (max 12 hours): delay after which a message read from SQS but 'not yet confirmed as fully processed by this consumer' will become visible again by another consumer.
- Type of queues:
- Default: best effort ordering, highly parallel, at least once but not exactly once
- FIFO: (first in first out): ordering guaranteed, exactly once delivery
- You can have duplicates if you don't manage very well your visibility timeouts.
Read the SQS faqs before taking the exam.
Amazon SWF (Simple Workflow Service) is an Amazon Web Services tool that helps developers coordinate, track and audit multi-step, multi-machine application jobs.
- To develop workflows (ex: delivering a book from AMZ warehouse)
- SWF vs SQS:
- Retention: 1 year for workflows (SWF) vs 14 days for messages (SQS)
- Task oriented API vs message oriented API
- Only once assignment and no duplication
- SWF keeps central track of all tasks/events vs SQS with multiple queues require app level tracking logic
SWF actors:
- SWF workflow starters: initiate a workflow (ex: new e-commerce order)
- SWF Decider: control the flow of tasks in a workflow execution
- SWF Workers: carry out the tasks
Amazon SNS enables message filtering and fan out to a large number of subscribers, including serverless functions, queues, and distributed systems. Additionally, Amazon SNS fans out notifications to end users via mobile push messages, SMS, and email.
- In the exams it will be around Auto Scaling questions.
- SNS stores copies of the messages on multiple AZ.
- Push-based
- It can notify through:
- AWS Lambda functions
- HTTP/S webhooks
- mobile push
- SMS
Amazon Elastic Transcoder a is media transcoding service.
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.
- You can enable cache
- Scaled automatically
- You can throttle requests
- Connect to CloudWatch to log all requests.
Amazon Kinesis makes it easy to collect, process, and analyze real-time, streaming data so you can get timely insights and react quickly to new information.
- Kinesis streams: It consists of shards, where each stream is saved and stored for 24h, up to 7 days. You can have multiple shards on each stream. A consumer then read from the shards and process the data.
- Kinesis Firehose: It doesn't have shards and their built-in persistence. So data traverses the Firehose. Data has to be processed immediately with lambda or stored in S3 for example.
- It can stream data to Amazon S3, Amazon Redshift, Amazon Elasticsearch Service, and Splunk.
- Kinesis Analytics: It allows you to analyze the data that exists in Kinesis Firehose of streams.
Provides identity federation: allows users to authenticate via a Web Identity Provider (Google, Facebook, Amazon)
Exam tips:
- First, the user identifies with the WebId provider via the user pool
- Then the AWS credentials (IAM role) are retrieved via the identity pool
User pool is used based, handles: registration, authentication, account recovery.
Identity pool authorizes access to the AWS resources.