APP (Architecture and Program Principles)

Recommended Books:

  • Clean Code
  • The Pragmatic Programmer

Architecture Section Preview

Loosely-Coupled System(SOA)

Challenges: how to define the Services and their interaction

Non-functional Requirements

Remote Interface (RESTful APIs)

Asynchronous Systems

Challenges:

  • need rethinking with an event-driven approach
  • cannot rely on remote services even more than before
  • Testing complicated

Reactive Concept

Stateless Decision Systems

Approach:

  • how to build decision system that can read to a dynamic state of the world
  • how to coordinate a collection of systems

Modern Architecture Concepts

Approach:

  • How to make the right tech and arch decisions for a given problems

Data Pipelines

Approach:

  • How to develop data-driven use cases

Coding Section Preview

Managing Technical Debt

Handling Logic Failures

Log , but how to prevent too much

Instrumenting for Verification

Approach: how to verify non-functional requirements

Unit and Regression Testing (Continuous ?)

Testing Asynchronous Code

Medical Device Marketplace

multi suppliers multi groups (with different hospitals ) negotiate online

Players:

  • hospitals
  • suppliers
  • manufactures
  • groups

Concept:

  • Contract (group, suppliers, negotiation)
  • Price Lists
  • Orders
  • Negotiation
  • Commitment
  • Historic Date (Read, Update, Delete )
  • Returns
  • Payment Terms

Action: CRUD

Behavior: Hospital <> Group

  • Negotiate Group, Suppliers, Items, Historic Date (optional, maybe first time)
  • Commitment Volumes, historical volumes
  • Volume, items, price when signing contract
  • volume, items, price when paying

Week 4

4. Error Handling, REST

  • bad request (get)
  • depending failure ()
  • internal error (login)
  • Bad code (global)

http status code

  • 2xx
    • 200
    • 201
  • 4xx (Client Side)
    • 400
    • 401
    • 403
    • 404
    • 405
  • 5xx (Error)
    • 500
    • 501
GET http://server/car/298

Response:

{
    statusCode: 404,
    errorCode: 1132, // (reserved not valid)
    errorMsg: 'Car is not a valid resource'
}

Table of error code & message:

Code Message Properties
1132 {} is not a resource   
POST /user

Possible error: 
1. Invalid resource (url not exist)
2. Empty Body
3. Invalid Format (XML, JSON)
4. Invaild Attribute
5. Missing Required Attribute
6. Id should not be provided
7. Duplication Attribute
8. Attribute not unique (email address, etc.)
9. Invaild Attribute value (type error)

Instrumentaion

  • Rate limites (day, hour, month)
    • log: count API calls by user/api key.
    • check against quota/limit
  • Measure Performance (Response, load)
    • timestamp
  • throttling
    • check for total api call count
  • Usage Patterns
    • logging
  • Logging -> Error
  • Documentation Errors

5. Persistence (database), API Version Management

6. Scale, Performance, Security

7. Async, Reactive programming, Data pipeline