One of my presentations in DevOps training session at Higgsup. This presentation is an introduction to Continuous Integration and best practices to apply Continuous Integration to your project. Topics covered in this session are: 1. Prerequisites for Continuous Integration 2. Problems with traditional software integration 3. What is Continuous Integration? 4. Why Continuous Integration? 5. How does Continuous Integration works? 6. Best practices of Continuous Integration 7. Summary

1. Continuous Integration
Presentation by
Hung Nguyen Huy

2. Contents
1. Prerequisites
2. Problems
3. What is Continuous Integration?
4. Why Continuous Integration?
5. How does Continuous Integration works?
6. Best practices of Continuous Integration
7. Summary

3. Prerequisites
● Version Control System
● Automation Testing
● Software Build
● Software Deployment

4. Version Control System (VCS)
● A system that records changes to a file or set of files over time.
● Every file
○ Has a full history of changes: records of Who did What, When, Why
○ Can be restored to any version at any time
● Benefits
○ Allows a team to manage/share source code
○ Keeps track of all versions of files
○ Possibility to recall specific versions of files
○ Allows simultaneous development of different features on the same codebase

5. Distributed Version Control System

6. Distributed Version Control System
Terminologies:
● Repository
● Clone
● Commit
● Pull/Push
● Branch
● Merge (Integrate)

7. Automation Testing
● The use of special software/tools to:
○ Control the execution of tests
○ Assert actual outcomes with expected outcomes
● Critical for CI/CD.

8. Software Build
What is software build?
● The process by which source code is converted in to a standalone software
artifact that can be run on a server
Build tools
● The process of building software is usually managed by a build tool
● Examples: Ant, Maven, Gradle,…

9. Software Deployment
● All of the activities that make a software available to use.
● Including installation, configuration, running, testing, and making necessary
changes,…

10. Problems

11. Problems
The Source of the Problem
● Traditional software integration
● Change conflicts
● Escalating Factors
Integration Hell

12. Continuous Integration (CI)

13. Solution: Integrate Continuously

14. What is Continuous Integration?
● a development methodology
● of daily developer integrations
● verified by automated builds (including tests)

15. Why Continuous Integration?

16. Why Continuous Integration?
Building Software can be a risky business
● Fixing bugs late is costly
● Lack of team cohesion
● Lack of project visibility
● Poor quality code base
● Lack of deployable software

17. Risk 01: Fixing bugs late is costly

18. Risk 02: Lack of team cohesion
● “Your changes to UserService conflicts with mine. How do we merge now?”
● “When did you change the Account API? I’m still using the old version in my
branch? How can I merge now?”
● “When did we decided to upgrade to version 2.0-alpha of iTextPDF?”
● ….

19. Risk 03: Lack of project visibility
● “What do you mean by the latest build was fail and the master branch was
broken?”
● “What do you mean the tests are failing?”
● “What’s in version 1.2.3 of the build?”
● “What’s our code coverage now? “

20. Risk 04: Poor quality code base
● “We have 3 classes doing the same thing???”
● “We have a function with thousand lines of code???”
● Coding standard violations
● Duplicated code!
● ….

21. Risk 05: Lack of deployable software
● “It works on my machine!”
● “I need a new build to test with” (QA)
● “The [boss|client|customer] is coming, we need to demo progress asap”

22. Use Continuous Integration
to reduce the risks

23. How CI works?
● What constitutes a build?
● When do I build?
● How do I build?
● CI Workflow

24. What constitutes a build?
● Compilation
● Test execution
● Database integration
● Code Inspection
● Document generation
● Feedback

25. Compilation
● Ensures code actually compiles
● Can be ignored in the case of interpreted languages.

26. Test Execution
● Ensures product functions as expected.
● Through repeatable testing.

27. Database Integration
● Ensures Database and Code in sync.
● Automates (re)creation of Database and test data.

28. Code Inspection
● Ensures a quality code base.
● Identifies problems early.
● Enforces best practices and coding standards.

29. Document Generation
● Automatically ensures software documentation is current.
● Produces build reports and metrics.

30. Feedback
Provide immediately feedback to developers and other stake-holders.

31. How do I build?
● Use a single build script
● That can run from the cmdline
● Do NOT depend on an IDE

32. Do it continuously!
● Use a dedicated CI server
● Trigger on ALL daily check-ins, not cron
● NOT only at midnight

33. Pay attention to your build
● Provide immediate feedback
● Make it easily accessible
● Require NO developer effort

34. Metrics matter
● Identify key metrics and track them visually
● Act on them immediately

35. CI Workflow

36. Best Practices

37. 1.
Commit Early,
Commit Often
Everyone commits to the Mainline EVERY DAY

38. 2.
NEVER commit broken code
Run private build first

39. 3.
Fix build failures immediately,
Avoid getting broken code

40. 4.
Fail Fast

41. 5.
Everyone can see what’s happening

42. 6.
Act on metrics

43. 7.
Build & Test in a clone
of the production environment

44. 8.
Create artifacts from every build
Make it easy for anyone to get the latest executable version

45. Summary
Continuous Integration
Can help you build better quality
software faster, with more
confidence

46. Thanks for listening!