Lessons learned from two decades of professional software development
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Dennis Doomen discusses key principles for maintainable code, including isolation, testability, being diagnosable, traceability, readability, and discoverability. The goal is code that can be changed confidently by any developer on a team without fear and has a low cognitive load for readers to understand. Dennis Doomen is focused on continuously improving code through these principles.
Lessons learned from two decades of professional software development
- 1. Dennis Doomen | @ddoomen | Aviva Solutions | The Continuous Improver
- 8. Isolation (can I do this without affecting anything else) Testability (is it doing what it is supposed to do) Diagnosable (why and when did this happen) Traceability (why did we do this) Readability of code (what does it try do and how) Discoverability (where is this done)
- 18. "Code that can be changed by any developer in the team without fear and with confidence" "Has a low cognitive load. The energy needed by your brain to read and comprehend the code"
- 32. Dennis Doomen @ddoomen Dennis Doomen | @ddoomen | The Continuous Improver
Editor's Notes
- #6: Understand the context of when a tool, practice or principle applies and when not. Don't reject it because of misuse (e.g. IoC, OR/M, DRY, TDD).
- #7: Design patterns are communication tools, not goals on itself
- #8: Gut feelings are really Design Heuristics Heuristics are ideas or experiences that give progress, but no guarantee
- #10: Monolith can't be avoided, unless you overengineer. A long-living monolith is a testament for success.
- #11: There's too much knowledge hidden in that old code. The new system may never catch up the old one It'll cost too much capacity to maintain old and new Instead, rebuild pieces bit by bit in the same code-base
- #12: Don't hide the magic Avoid inheritance Control dependencies
- #13: Explicit ownership of each repository Adopt Github Contribution through pull requests Standardize read-me explaining code of conduct for contributions
- #14: Captures important decisions and changes What was the problem, what were the options, what was chosen en why and what does it mean for other devs
- #15: Technology is almost never a solution to a problem (except for OWIN, Git, .NET Core). Unless you rebuild a piece
- #16: Be consistent within a boundary, don't bother outside (allow different patterns for different solutions) Architectural seams
- #17: Understand the layers of testing Test the boundary, not the internals Clear cause and effect Show what's important. Hide what's not. Avoid DRY
- #18: Makes it easier to rebuild pieces Avoids too much coupling Consider DIP No common/foundation/shared stuff Be consistent within a boundary, don't bother outside (allow different patterns for different solutions)
- #19: Reads like a book Acknowledges the Magic Number of Seven Code explains the what and how.. …so doesn't obscure the algorithms Aligns code with the boundaries
- #20: Don't use static mutable state May seem convenient, but they hurt you
- #21: Build local as you build remote Treat your build process as first-class citizens PSake, Cake or Nuke
- #22: Clear Source Control History Track the why of a changeset/commit, not just the what Separate refactoings from functional changes Don't squash unrelated changes
- #23: You are not the only audience Logging statements Exceptions Configuration surface
- #25: You are not the only audience Logging statements Exceptions Configuration surface
- #26: You are not the only audience Logging statements Exceptions Configuration surface
- #27: After 1.0, be responsible Choose a release strategy Apply SemVer Avoid breaking changes Document your code
- #28: Understand the audience and accuracy of your documentation
- #29: Technical Debt is inevitable. Plan for it. (e.g. 20% per release)
- #30: Keep refactoring -> code rot => boy scout rule Natural Cause of Refactoring
- #31: Work with somebody that has radical/out-of-the-box ideas and then find a middle ground
- #32: Don't take anything at face value (especially speakers at conferences and events)