3 - Architecture and Patterns

Question 1

6 patterns in serverless:

Answer 1

Command, Messaging , Priority queue, Fan-out, Compute as glue, Pipes and filters

Question 2

What is Command Pattern?

Answer 2

Encapsulates a request as an object, thereby letting you parameterize clients with different req, queue or log req, & support undoable op.
Req is send to the invoker. Invoker pass it to the encapsulated command obj. Obj passes req to the appropriate method of Receiver to perform specific action.

Question 3

What is a Messaging pattern

Answer 3

Popular in dist sys because they allow dev to build scalable & robust syst by (1) decoupling fuc & services from direct dep and (2) allowing storage of events/records/req in a queue
Features a msg queue with a sender that can post to the queue & a receiver that can retrieve msg from the queue. In AWS, this pattern can be built on top of SQS

Question 4

What is Priority queue pattern

Answer 4

System where there is entirely different workflows for msg of different priority

Question 5

Fan-out pattern

Answer 5

Pattern that pushes a msg to all listening/subscribed clients of a particular queue/msg pipeline.
Useful when needed to invoke multiple Lamba func at same time. In AWS, it is usually implemented using SNS topics.

Question 6

Compute as glue architecture

Answer 6

Use Lambda function to create powerful execution pipelines & workflows. Lamba is the glue btw services