Episode 3: Defensive Programming in a Low Code Environment

by Imran Kasam & Steve Ledwith

Published on 4 June 2020. This is approximately 50 minutes long. This episode is sponsored by Anchor.fm.

Overview

In this episode we dive into the topic of Defensive Programming with a focus on how to be defensive in a low code / no code platform. We talk about best practices, SDLC, coupling, and cohesion, and much more!

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Show Notes

Defensive Programming Slide Deck

Timing for the topics is approximate, and meant to help you find specific parts of the conversation.

Definition of Defensive Programming

  • Philosophy of writing code with the intention of handling unintended and unforeseen errors, bugs, and circumstances
  • Defensive Design for the Web

1 min: Decisions we make as developers

Todoist

Write an application which is correct

  • Write code easy enough to understand so you don’t need documentation

Slide deck we’re discussing in this episode

3 min: Why talk about defensive programming?

Not much out there about defensive programming in low code available today.

Mendix

6 min: Goal of defensive programming

  • Correctness
  • Clarity
  • Readability
  • Bug-prevention

Annotations - best practice in Mendix Studio Pro - Using Annotations

7:45 min: Stay away from early optimization!

Use Studio Pro to break down a long micro flow which you know works

  • Refactor after you have it working, not during the process

10 min: Slide 4 - two similar micro flows, early version, and late version

RESO Unique Organization Identifier (UOI) API

12 min: High level description of creating things in Mendix

13:50 min: Naming conventions

  • How do you make sure you can have a consistent naming scheme?

Tools to scan your code for best practice implementation

18 min: Training materials from Mendix

19 min: Defensive Programming is more than error checking

  • Planning
  • Architecture diagrams
  • Shared context
  • All parts of the SDLC help improve code
  • Story refinements help understand what you’re trying to accomplish

21 min: Slide 6 - design patterns, even in low code

  • Create or Retrieve existing

Slide 7 - validation micro flow to ensure you have good data

A word from our sponsor - Anchor.FM

Anchor.fm

Slide 8: XPath selection

26 min: XPath order of constraints

  • You need the first element to give you the most bang for the buck

Understand how your application will be used

  • Think about the data you have to display, and ensure you’re making the application work correctly
  • Keep in mind you’ll have to refactor as your application grows
  • Do the most optimal for the audience or user base

30 min: Fail gracefully

  • How do you allow the app to fail without leaving the user stuck
  • Can you horizontally scale to keep the app running?

32 min: Dealing with bad user input

  • Provide specific information to the user
  • Handle errors and give back something useful
  • Enable your production support team

Behind the scenes, write log information; provide the team the information necessary to solve the issue

  • Write actionable log messages for the developers or production support

35 min: Mock data service

  • Good data, mixed data, bad data
  • Think about how you can easily generate data for testing and proving your defensive development
  • Mock Data Generator - example

Happy path

37 min: External services can change without you knowing

  • Can you be defensive enough to handle unexpected changes?
  • This isn’t low code, it’s every language

39 min: Cohesion and Coupling

  • Cohesion
    • the amount to which the components of an object relate to each other.
    • The goal is to increase cohesion
  • Coupling
    • the amount to which two objects are dependent upon each other’s behavior.
    • The goal is to reduce coupling

Don’t Future Proof Yourself

Don’t let perfect get in the way of better

43 min: Review your logs, understand how your application is being used

  • Address the issues you see in the logs
  • Make sure you’re not leaving your users stuck in your app

What’s the first thing to think about in Defensive Programming in Low Code / Mendix

  • All of the general software best practices still apply
  • Give thought to what you’re doing, and what you’re trying to accomplish

45 min: Readability in Mendix

  • Straight lines and decision trees in Mendix
  • Layout of the micro flow is similar to the Tab vs Space discussion
  • Shout out to //+

Rapid development allows you to make things that don’t work if you don’t pay attention.

Final Wrap up

  • Readability
  • Modularity
  • Naming Conventions
  • Design Thinking
  • Checking for Bad Data

Future Topics

  • Error handling
  • Logging
  • Troubleshooting