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Agile
- 1. Overview of Agile Methodology By Komal Khetlani
- 2. Software development processes A [really] short history of
- 3. traditional approach to software development REQUIREMENTS DESIGN DEVELOPMENT TESTING MAINTENANCE Waterfall Development is another name for the more Waterfall Development
- 4. Waterfall Development (contd..) You complete one phase (e.g. design) before moving on to the next phase (e.g. development) You rarely aim to re-visit a ‘phase’ once it’s completed. That means, you better get whatever you’re doing right the first time!
- 5. This approach is highly risky, often more costly and generally less efficient than Agileapproaches REQUIREMENTS DESIGN DEVELOPMENT TESTING MAINTENANCE Takes too long Changes Skipped You don’t realize any value until the end of the project You leave the testing until the end You don’t seek approval from the stakeholders until late in the day But…
- 6. AGILEIterative AdaptableRapid Cooperative Quality-driven Not a process, it's a philosophy or set of values
- 7. Individuals and interactions over processes and tools Working software over comprehensive documentation Customer collaboration over contract negotiation Responding to change over following a plan Agile Manifesto
- 8. Agile Umbrella Agile Crystal XPScrum DSDM FDD Kanban RUP RUP (120+) XP (13) Scrum (9) Kanban (3) Do Whatever!! (0) More Prescriptive More Adaptive and few more… * Check wikipedia for list of all Agile methods RUP has over 30 roles, over 20 activities, and over 70 artifacts more rules to follow fewer rules to follow
- 9. Agile Methodologies • eXtreme Programming (XP) • Scrum • Crystal family of methodologies • Feature-Driven Development (FDD) • Adaptive Software Development (ASD) • Dynamic System Development Model (DSDM) • Agile Unified Process (AUP)
- 10. ScrumA light-weight agile process tool Split your organization into small, cross-functional, self- organizing teams. Split your work into a list of small, concrete deliverables. Sort the list by priority and estimate the relative effort of each item. Scrum Team Scrum Master Product/ Project Owner
- 11. Split time into short fixed-length iterations/ sprints (usually 2 – 4 weeks), with potentially shippable code demonstrated after each iteration. Scrum (contd..) January May Optimize the release plan and update priorities in collaboration with the customer, based on insights gained by inspecting the release after each iteration. Optimize the process by having a retrospective after each iteration.
- 13. Iterative Scrum
- 14. Things we do in Scrum The project/ product is described as a list of features: the backlog. The features are described in terms of user stories. The scrum team estimates the work associated with each story. Features in the backlog are ranked in order of importance. Result: a ranked and weighted list of product features, a roadmap. Daily scrum meeting to discuss What did you do y’day? What will you do today? Any obstacles? Scrum terminologies
- 15. Scrum Artifacts Iteration/ Sprint 1 Iteration/ Sprint 2 Sample Userstory Efforts 10hrsEfforts: 2hrs IA, 6hrs Development, 2hrs Testing The total effort each iteration can accommodate leads to number of user story per iteration One release may contains number of iterations Release
- 16. Scrum planning example Iteration cycle of 3 weeks Working hours per day is 8 120hrs Total hours of work iteration can accommodate 8hrs x 5days x 3weeks = Product backlog of 20 stories Each story effort is 10 hrs Iteration backlog or number of stories per iteration 12 user story
- 17. Scrum in a nutshell So instead of a large group spending a long time building a big thing, we have a small team spending a short time building a small thing. But integrating regularly to see the whole.
- 18. KANBANJust-in-time (JIT) Visualize the Work Measure & Manage Flow Signboard Limit Work-In-Progress Visual Card
- 19. KanbanLean approach to agile development Similar to Scrum in the sense that you focus on features as opposed to groups of features – however Lean takes this one step further again. You select, plan, develop, test and deploy one feature (in its simplest form) before you select, plan, develop, test and deploy the next feature. Aim is to eliminate ‘waste’ wherever possible…
- 20. Kanban (contd…) Visualize the workflow Limit WIP (work in progress) Split the work into pieces, write each item on a card and put on the wall Use named columns to illustrate where each item is in the workflow Assign explicit limits to how many items may be in progress at each stage Measure the lead time (average time to complete one item, sometimes called “cycle time”) Optimize the process to make lead time as small and predictable as possible
- 21. Kanban Board Illustration - I
- 22. Kanban Board Illustration - II
- 23. Extreme Programming • Most prominent Agile Software development method • Prescribes a set of daily stakeholder practices • “Extreme” levels of practicing leads to more responsive software. • Changes are more realistic, natural, inescapable.
- 25. The XP Guru: Kent Beck • eXtreme Programming – The most prominent agile development methodology
- 27. The 12 Key Practices • The Planning Game • Small Releases • Metaphor • Simple Design • Test-Driven Development • Refactoring • Pair Programming • Collective Ownership • Continuous Integration • 40-Hour Workweek • On-site Customer • Coding Standards
- 28. 1. Metaphor • Guide all development and conversations with a simple shared story of how the whole system works – Gives the team a whole picture of describing the system, where new parts fit, etc. • Words used to identify technical entities should be chosen from the metaphor • The default metaphor is the business domain, and it’s usually just fine
- 29. How It Works for Me? • Metaphors are good idea • People should know the business needs and how their work fits in the project
- 30. 2. Release Planning • Requirements via User Stories – Short cards with natural language description of what a customer wants – Prioritized by customer • Resource and risk estimated by developers – Via “The Planning Game” • Play the Planning Game after each increment
- 31. User Stories
- 32. How It Works for Me? • Requirements specification (SRS) is better than user stories – Written documentation works well for large projects • I prefer prototyping the user interface as source of documentation • Sometimes its is hard to estimate the required resources • Small releases have less risk
- 33. 3. Testing • Test-Driven Development (TDD) – Write tests before code – Tests are automated – Often use xUnit framework – Must run at 100% before proceeding • Acceptance Tests – Written with the customer – Acts as “contract” – Measure of progress
- 34. Test-Driven Development • Developers write unit tests before coding • Motivates coding – Improves design – Provides regression tests – Provides specification by example public void TestMultiplication() { Dollar five = Money.dollar(5); AssertEqual(new Dollar(10), five.times(2)); AssertEqual(new Dollar(15), five.times(3)); }
- 35. How It Works for Me? • TDD is good for most projects, not for all – The real world is different: you always need the functionality "for tomorrow"! • I use unit testing for complex logic only – Testing simple logic is overhead
- 36. 4. Pair Programming • Two software engineers work on one task at one computer – The driver has control of the keyboard and mouse and creates the implementation – The navigator watches the driver’s implementation • Identifies defects and participates in on-demand brainstorming – The roles of driver and observer are periodically rotated
- 37. Pair Programming • Pairs produce higher quality code • Pairs complete their tasks faster • Pairs enjoy their work more • Pairs feel more confident in their work
- 38. How It Works for Me? • Pair programming is great for complex and critical logic – When developers need good concentration – Where quality is really important – Especially during design – Reduces time wasting • Trivial tasks can be done alone • Peer reviews instead pair programming is often alternative
- 39. 5. Refactoring • Improve the design of existing code without changing its functionality – Relies on unit testing to ensure the code is not broken • Bad smells in code: – Long method / class – Duplicate code – Methods does several different things (bad cohesion) – Too much dependencies (bad coupling) – Complex / unreadable code
- 40. How It Works for Me? • Delivering working software faster is important! – You can write the code to run somehow • With simple design • With less effort – Later you can refactor the code if necessary • Refactoring is not a reason to intentionally write bad code! – Good coding style is always important!
- 41. 6. Simple Design • No Big Design Up Front (BDUF) – Reduces the overhead – Ship working functionality faster and get feedback early • “Do The Simplest Thing That Could Possibly Work” – Later use refactoring to change it • Not too much formal documentation
- 42. How It Works for Me? • Simple design does not mean "no design" –It is about establishing priorities –It's a set of tradeoffs you make –If something is important for this release and for the whole system, it should be designed well –Don't lose time to design something you will not use soon!
- 43. 7. Collective Code Ownership • Code to belongs to the project, not to an individual engineer! • Any engineer can modify any code • Better quality of the code • Engineers are not required to work around deficiencies in code they do not own – Faster progress – No need to wait for someone else to fix something
- 45. How It Works for Me? • Collective code ownership is absolutely indispensable – You need to fight the people who don't agree with this! – Fire people writing unreadable and unmaintainable code – Don't allow somebody to own some module and be irreplaceable
- 46. 8. Continuous Integration • Pair writes up unit test cases and code for a task (part of a user story) • Pair unit tests code to 100% • Pair integrates • Pair runs ALL unit test cases to 100% • Pair moves on to next task with clean slate and clear mind • Should happen once or twice a day
- 47. How It Works for Me? • Integrating often is really valuable – Sometimes you cannot finish a task for one day and integrate it – For small projects with small teams integration is not an issue – For large and complex projects it's crucial • Think of automated build environment
- 48. 9. On-Site Customer • Customer available on site – Clarify user stories – Make critical business decisions • Developers don’t make assumptions • Developers don’t have to wait for decisions • Face to face communication minimizes the chances of misunderstanding
- 49. How It Works for Me? • On-site customer actually does not work! – Customers are busy • Meetings every day is working better – Customers are not competent! • Customers always say "Yes, this is what I want" and later say the opposite • You need to think instead of them • Use prototyping
- 50. 10. Small Releases • Timeboxed • As small as possible, but still delivering business value – No releases to ‘implement the database’ • Get customer feedback early and often • Do the planning game after each iteration – Do they want something different? – Have their priorities changed?
- 51. How It Works for Me? • Small releases are really valuable – Manage the risk of delivering something wrong – Helps the customer to define better requirements • Release every few weeks • Large projects are not so flexible – Try to release something, even you know that it will be changed
- 52. 11. Forty-Hour Work Week • Kent Beck says, “ . . . fresh and eager every morning, and tired and satisfied every night” • Burning the midnight oil kills performance • Tired developers make more mistakes – Slows you down more in the long run • If you mess with people’s personal lives (by taking it over), in the long run the project will pay the consequences
- 53. How It Works for Me? • 40 hours a week or 40 hours without a sleep? – Come back to the real world! – Overtime is not recommendable but often can not be avoided • Better planning can help • Highly skilled senior engineers always suffer of overtime and high pressure – That's how the business works!
- 54. 12. Coding Standards • Use coding conventions – Rules for naming, formatting, etc. – Write readable and maintainable code • Method commenting – Self-documenting code – Don't comment bad code, rewrite it! • Refactor to improve the design • Use code audit tools (FxCop, CheckStyle, TFS)
- 55. How It Works for Me? • Coding standards are important – Enforce good practices to whole the team – tools, code reviews, etc. • Standards should be simple – Complex standards are not followed – Standards should be more strict for larger teams – Developers don't like utter rules like "comment any class member"
- 56. The 13th Practice? The Stand Up Meeting • Start the day with 15-minute meeting – Everyone stands up (so the meeting stays short) in circle – Going around the room everyone says specifically: • What they did the day before • What they plan to do today • Any obstacles they are experiencing – Can be the way pairs are formed
- 57. People Communicate Most Effectively Face-to- Face Richness of the communication channel Communicationeffectiveness 2 people at whiteboard 2 people on phone 2 people on email Videotape Paper
- 58. How XP Solve Some SE Problems Problem Solution Slipped schedule Short development cycles Cancelled project Intensive customer presence Cost of changes Extensive, ongoing testing, system always running Defect rates Unit tests, customer tests Misunderstand the business Customer part of the team Business changes Changes are welcome Staff turnover Intensive teamwork
- 59. So What does XP Apply to? • Domains with changing requirements • High-risk projects (including those with high schedule risk) • Small project team: 2 – 12 programmers – Cannot be used with a large team • Extended development team – Developers, managers and customer – Co-located • Automated testability
- 60. Agile Unified Process • AUP is a simplified version of RUP Phases of AUP Inception Elaboration Construction Transition
- 61. Disciplines of AUP Model Implementation Test Deployment Configuration Management Project Management Environment
- 62. Resources • Agile 101 http://agile101.net/2009/09/08/the-difference-between-waterfall-iterative- waterfall-scrum-and-lean-in-pictures/ • Kanban and Scrum - making the most of both http://www.infoq.com/minibooks/kanban-scrum-minibook • Kanban kick-start example http://www.limitedwipsociety.org/tag/kanban-board/
- 63. Thank You
Editor's Notes
- The meanings of the Manifesto items on the left within the agile software development context are described below. Individuals and Interactions – in agile development, self-organization and motivation are important, as are interactions like co-location and pair programming. Working software – working software will be more useful and welcome than just presenting documents to clients in meetings. Customer collaboration – requirements cannot be fully collected at the beginning of the software development cycle, therefore continuous customer or stakeholder involvement is very important. Responding to change – agile development is focused on quick responses to change and continuous development
- Prescriptive means “more rules to follow” and adaptive means “fewer rules to follow”.
- 9/1/201707/16/96
- 9/1/201707/16/96
- 9/1/201707/16/96