![Larry Tesler
Tesler’s Law of the Conservation of Complexity
Every application has an inherent
amount of irreducible complexity.
The only question is: who will have
to deal with it […]?
“
”](https://image.slidesharecdn.com/asimplertime-copenhagen-150516114948-lva1-app6892/85/A-Simpler-Time-A-study-of-complexity-in-APIs-27-320.jpg)
A Simpler Time: A study of complexity in APIs
- 1. A Simpler Time Ronnie Mitra Director of API Design CA API Academy ronnie.mitra@ca.com @mitraman
- 2. Simplicity.
- 5. Use picture of cellular automo complexité Complexity
- 6. What is Complexity? • Composed of many parts • Intricate, elaborate, interconnected • Difficult to process, resource intensive
- 9. Systems Complexity: Emergence The action of the whole is more than the sum of the actions of the parts
- 12. Performance Credit-Assignment Rule-Discovery Agent Structure (Holland) How do agents adapt?
- 13. Performance Credit-Assignment Rule-Discovery Agent Structure (Holland) “What will I do?” The stock price is low buy stock
- 14. Performance Credit-Assignment Rule-Discovery Agent Structure (Holland) the price has gone down, I’ve lost money “How well am I doing?”
- 15. Performance Credit-Assignment Rule-Discovery Agent Structure (Holland) “What else can I try?” Next time, identify market trends before buying
- 16. Emergent and Adaptive Behaviour • Agents become specialized • Behaviour is de-centralized • The system can adapt to change
- 18. Complexity in Design Different Perspectives Similar Conclusions
- 19. Cognitive Complexity: Norman “Complexity by itself is neither good nor bad: it is confusion that is bad.”
- 20. Reduce Organize Time Learn Differences Context Emotion Trust The One Cognitive Complexity: Maeda “Simplicity is about subtracting the obvious and adding the meaningful”
- 22. Complexity is a Perceived Quality interface simple confusing
- 23. Making Interfaces Simpler The designer’s job is to manage complexity: • improve learnability • improve usability • reduce confusion
- 25. Where Does Interface Complexity Come From? complexity is the price we pay for utility
- 26. Fred Brooks The complexity of software is an essential property not an accidental one. Hence descriptions of a software entity that abstract away its complexity often abstract away its essence. No Silver Bullet – Essence and Accident in Software Engineering
- 27. Larry Tesler Tesler’s Law of the Conservation of Complexity Every application has an inherent amount of irreducible complexity. The only question is: who will have to deal with it […]? “ ”
- 29. OAuth 2.0 Complexity: A Fictional Measurement OAuth 2.0 Complexity (if we could measure it)
- 30. Managing OAuth 2.0 Complexity: Who Pays the Price? OAuth 2 Client Implementation OAuth 2 Server Implementation !!!
- 32. Managing Complexity: Microservices Monolith Application Microservices Application μService API μService μService μService μService μService API API API API API API
- 33. Managing Complexity: The Monolith Monolith Application API Who pays the complexity price? Code Maintainer System Maintainer
- 34. Managing Complexity: Microservices Who pays the complexity price? Code Maintainer System Maintainer Microservices Application μService μService μService μService API API API API
- 35. Managing Complexity: Microservices • Service becomes less confusing, but system complexity increases • Complexity cost is worthwhile • Tools are introduced to hide (shift) complexity containerization discovery deployment …
- 36. Managing Complexity: Microservices boundaries μService μService μService μService μService μService client application API API API API API API
- 37. Managing Complexity: Microservices Who pays the complexity price? Code Maintainer System Maintainer Microservices Application μService μService μService μService API API API API Client App Developer
- 38. Managing Complexity: Client Applications μService μService μService μService μService μService client application API API API API API API SDK API
- 39. Complexity and the API Lifecycle
- 41. API Lifecycle at Higher Resolution API Software Life Cycle API Documentation Life CycleAPI Tooling Life Cycle
- 43. • complexity enters the system
- 44. Inherited Complexity world organization system interface
- 45. • complexity is managed by designers • developers deal with application complexity
- 46. Complexity in API Design: Pagination response data page page page page page
- 47. Complexity in API Design: Pagination Strategies no pagination offset and count fixed page size “smart” pagination What are the complexity implications of pagination strategies?
- 48. • complexity is perceived externally • operators deal with operational complexity
- 51. Adaptive system Increased reliability System Complexity as a Feature Performance Credit-Assignment Rule-Discovery
- 52. client application API API API API API API Extending the System Boundary
- 54. 1. Accept complexity 2. Manage complexity for humans 3. Incorporate system complexity as a feature
- 55. simple
- 56. simple Image Credits "Ribosome-Nascent chain complex". Licensed under CC BY 3.0 via Wikipedia - http://en.wikipedia.org/wiki/File:Ribosome- Nascent_chain_complex.png#/media/File:Ribosome-Nascent_chain_complex.png "Sao Paulo Stock Exchange" by Rafael Matsunaga - Flickr. Licensed under CC BY 2.0 via Wikimedia Commons - http://commons.wikimedia.org/wiki/File:Sao_Paulo_Stock_Exchange.jpg#/media/File:Sao_Paulo_Stock_Exchange.jpg "Appearance of sky for weather forecast, Dhaka, Bangladesh" by Mohammed Tawsif Salam - Own work. Licensed under CC BY-SA 3.0 via Wikimedia Commons - http://commons.wikimedia.org/wiki/File:Appearance_of_sky_for_weather_forecast,_Dhaka,_Bangladesh.JPG#/media/File:Appearance_of_sky_for_weather_forecast ,_Dhaka,_Bangladesh.JPG Snow Geese 03 by TexasEagle – Flickr. . Licensed under CC BY 2.0 - http://www.flickr.com/photos/texaseagle/4206741477/sizes/o/
- 57. A Simpler Time Ronnie Mitra Director of API Design CA API Academy ronnie.mitra@ca.com @mitraman
Editor's Notes
- #8: I want to focus on two major types of complexity: system complexity, which captures some of the properties of intracacy and many parts that we’ve mentioned. Also what I’m calling “cognitive complexity”, the type of complexity related to human understanding. There are other types of complexity that we won’t discuss, for example I’m not going to talk about computational complexity – the study of the resources required to solve computational problems and the feasability of solving them. That is an interesting type of complexity, but not as releveant to the direction I want to take us today.
- #9: As I’ve said, I’m definitely not an expert in complexity. Most of what I learned about the science of complexity has come from these two books – aimed at laymen like myself. If this subject is new to you and you find it interesting, I can recommend both of these titles: Complexity: A Very Short Introduction by John Holland And Complexity: A guided Tour by Melanie Mitchell
- #10: Focus on emergent behaviour here as this is the essence of systems complexity Weather is an emergent system
- #11: Goverened by laws (e.g. physics) Static/fixed agents Weather, von-neuman’s celleular automata
- #12: Agents react/adapt Rare to find equillibrium (steady state)
- #13: SHE: Shrink, Hide, Embody
- #14: SHE: Shrink, Hide, Embody
- #15: SHE: Shrink, Hide, Embody
- #16: SHE: Shrink, Hide, Embody
- #17: SHE: Shrink, Hide, Embody
- #18: Systems complexity is fascinating, but I want to talk about something that is more interesting to me.. Cognitive complexity.
- #19: Intro to microservices Complexity in application: harder to learn, harder to develop, harder to change Complexity in management: harder to model, harder to measue, harder to enforce policy Embracing management complexity: Netflix model, celluar
- #20: Intro to microservices Complexity in application: harder to learn, harder to develop, harder to change Complexity in management: harder to model, harder to measue, harder to enforce policy Embracing management complexity: Netflix model, celluar
- #21: SHE: Shrink, Hide, Embody
- #27: Brooks is talking specifically about programming in this essay. Accidental complexity is the cruft. Complexity introduced because you are providing functions that are unneeded, or you haven’t been able to optimize the functions that are needed. The accidental complexity is the type of complexity Maeda talks about subtracting.
- #28: Lawrence Gordon Tesler (born April 24, 1945) is a computer scientist who works in the field of human–computer interaction. Tesler has worked at Xerox PARC, Apple, Amazon, and Yahoo!. He is the creator of the copy/paste interaction He invented the law to sell the case for a framework and generic application layer within Apple. His argument was that it was better to push complexity down into the framework rather than making the user pay the price.
- #33: Intro to microservices Complexity in application: harder to learn, harder to develop, harder to change Complexity in management: harder to model, harder to measue, harder to enforce policy Embracing management complexity: Netflix model, celluar
- #34: Intro to microservices Complexity in application: harder to learn, harder to develop, harder to change Complexity in management: harder to model, harder to measue, harder to enforce policy Embracing management complexity: Netflix model, celluar
- #35: Intro to microservices Complexity in application: harder to learn, harder to develop, harder to change Complexity in management: harder to model, harder to measue, harder to enforce policy Embracing management complexity: Netflix model, celluar
- #36: System complexity can be addressed, it is much harder to address the cognitive complexity of understanding code. i.e. this is an easier problem to solve.
- #37: Intro to microservices Complexity in application: harder to learn, harder to develop, harder to change Complexity in management: harder to model, harder to measue, harder to enforce policy Embracing management complexity: Netflix model, celluar
- #38: Intro to microservices Complexity in application: harder to learn, harder to develop, harder to change Complexity in management: harder to model, harder to measue, harder to enforce policy Embracing management complexity: Netflix model, celluar
- #39: Intro to microservices Complexity in application: harder to learn, harder to develop, harder to change Complexity in management: harder to model, harder to measue, harder to enforce policy Embracing management complexity: Netflix model, celluar
- #41: A very product-centric view of the API lifeycle from the nordicapis team. This is also very macro – it is high level, if we go into details we find other lifecycles we need to worry about.
- #42: Intro to microservices Complexity in application: harder to learn, harder to develop, harder to change Complexity in management: harder to model, harder to measue, harder to enforce policy Embracing management complexity: Netflix model, celluar
- #43: A very product-centric view of the API lifeycle from the nordicapis team. This is also very macro – it is high level, if we go into details we find other lifecycles we need to worry about.
- #44: A very product-centric view of the API lifeycle from the nordicapis team. This is also very macro – it is high level, if we go into details we find other lifecycles we need to worry about.
- #45: How do committees invent – Mel Conway
- #46: A very product-centric view of the API lifeycle from the nordicapis team. This is also very macro – it is high level, if we go into details we find other lifecycles we need to worry about.
- #47: Intro to microservices Complexity in application: harder to learn, harder to develop, harder to change Complexity in management: harder to model, harder to measue, harder to enforce policy Embracing management complexity: Netflix model, celluar
- #48: Intro to microservices Complexity in application: harder to learn, harder to develop, harder to change Complexity in management: harder to model, harder to measue, harder to enforce policy Embracing management complexity: Netflix model, celluar
- #49: A very product-centric view of the API lifeycle from the nordicapis team. This is also very macro – it is high level, if we go into details we find other lifecycles we need to worry about.
- #50: A very product-centric view of the API lifeycle from the nordicapis team. This is also very macro – it is high level, if we go into details we find other lifecycles we need to worry about.
- #51: The frequency of the lifecycle is bound by how the products we create are consumed
- #53: We could achieve emergence This would help with lifecycle frequency, less risk of changes