JAX London 2011

1. Effective Development with...
Eclipse, Mylyn, Git, Gerrit and Hudson (Jenkins)
Chris Aniszczyk (Red Hat)
Principal Software Engineer
zx@redhat.com
http://aniszczyk.org

2. About Me
Hack on Eclipse, OSGi, Git and other things at Red Hat
Member of the Eclipse Board of Directors
Member in the Eclipse Architecture Council
I like to run! (2 minutes over of Boston qualifying ;/)
Co-author of RCP Book (www.eclipsercp.org)
Starting a new book on Git and Gerrit...
Effective Development with Mylyn, Hudson, Git and Gerrit | © 2011 by Chris Aniszczyk

3. Agenda
Introduction
- Mylyn Reloaded
Hudson (Jenkins) and Mylyn
Distributed Version Control (DVCS)
Code Review with Git, Gerrit and Mylyn
Conclusion
Q&A
Effective Development with Mylyn, Hudson, Git and Gerrit | © 2011 by Chris Aniszczyk

4. What is Mylyn?
Mylyn is the task and application lifecycle
management (ALM) framework for Eclipse. It
provides...
The task-focused interface that realigns
the IDE around tasks so that you see only
the code that's relevant
A task management tool for developers
A broad ecosystem of Agile and ALM
integrations. There are dozens of extensions
integrate Mylyn with ALM and developer
collaboration tools
Effective Development with Mylyn, Hudson, Git and Gerrit | © 2011 by Chris Aniszczyk

5. Mylyn Integrates within the IDE
Mylyn reduces context switching...
Effective Development with Mylyn, Hudson, Git and Gerrit | © 2011 by Chris Aniszczyk

6. Mylyn History
2004: Task-focused interface ideas on UBC whiteboard
2006: v1.0, early adopters help evolve the UI
2007: v2.0, API grows from integration needs, increasing
2008: v3.0, API solidifies, extensions increase
2009: v3.3, de facto ALM integration for Eclipse, dozens of
extensions
2010: Expansion of participation and new project creation
2011: Mylyn 3.5
Effective Development with Mylyn, Hudson, Git and Gerrit | © 2011 by Chris Aniszczyk

7. Mylyn 3.4
Tasks Bugzilla Trac OSLC
Context Java C/C++
Versions CVS
Docs WikiText
Effective Development with Mylyn, Hudson, Git and Gerrit | © 2011 by Chris Aniszczyk

8. Mylyn 3.5 – Restructured
Tasks Bugzilla Trac OSLC
Context Java C/C++
Versions CVS Git OSLC
WikiText RichText
Docs
Builds Hudson OSLC
Reviews Tasks Gerrit IEEE
Effective Development with Mylyn, Hudson, Git and Gerrit | © 2011 by Chris Aniszczyk

9. Agenda
Introduction
Hudson (Jenkins) and Mylyn
- What is Hudson (Jenkins)
- Mylyn Builds
The Rise of Distributed Version Control (DVCS)
Code Review with Git, Gerrit and Mylyn
Conclusion
Q&A
Effective Development with Mylyn, Hudson, Git and Gerrit | © 2011 by Chris Aniszczyk

10. What is Hudson (Jenkins)?
Hudson is an extensible continuous integration server
Easy to use
Tons of plug-ins
Very popular within the Java community
Recently forked by the community via Jenkins
Effective Development with Mylyn, Hudson, Git and Gerrit | © 2011 by Chris Aniszczyk

11. Mylyn Builds
“The scope of the Mylyn Builds project is integration of
continuous integration and build systems (eg., Hudson)
within Eclipse. In addition to the seamless access to
software build and assembly technologies. Mylyn users
will be able to access continuous integration processes,
control build execution and associate build results with
tasks and context.”
http://eclipse.org/mylyn/builds
You'll find yourself leaving Eclipse less!
Effective Development with Mylyn, Hudson, Git and Gerrit | © 2011 by Chris Aniszczyk

12. Mylyn Builds Demo
Effective Development with Mylyn, Hudson, Git and Gerrit | © 2011 by Chris Aniszczyk

13. Agenda
Introduction
Hudson (Jenkins) and Mylyn
Distributed Version Control (DVCS)
- Why DVCS? Why Git?
- Lessons learned at Eclipse moving to Git
- Mylyn Versions and EGit
Code Review with Git, Gerrit and Mylyn
Conclusion
Q&A
Effective Development with Mylyn, Hudson, Git and Gerrit | © 2011 by Chris Aniszczyk

14. Version Control
Version Control Systems manage change
“The only constant is change” (Heraclitus)
Effective Development with Mylyn, Hudson, Git and Gerrit | © 2011 by Chris Aniszczyk

15. Why Version Control?
VCS became essential to software development because:
They allow teams to collaborate
They manage change and allow for inspection
They track ownership
They track evolution of changes
They allow for branching
They allow for continuous integration
Effective Development with Mylyn, Hudson, Git and Gerrit | © 2011 by Chris Aniszczyk

16. “Hey, get back to work!”
… “My code's merging” - remember those days you
spent merging in changes in CVS/SVN?
Effective Development with Mylyn, Hudson, Git and Gerrit | © 2011 by Chris Aniszczyk

17. Version Control: The Distributed
Every client has a copy of the full repository locally
All repository operations are local (except sharing)
Intelligent network operations when sharing content
A very non linear revision history
Large online communities to share changes
Effective Development with Mylyn, Hudson, Git and Gerrit | © 2011 by Chris Aniszczyk

18. Software Trends and Revolution
Most major open source projects use some form of DVCS
Git, Hg, Bazaar
Linux
MySQL
OpenJDK
Android
JQuery
Gnome
Fedora
Bugzilla and so on...
But why?
Effective Development with Mylyn, Hudson, Git and Gerrit | © 2011 by Chris Aniszczyk

19. Benefits of Distributed Version Control
Can collaborate without a central authority
Disconnected operations
Easy branching and merging
Define your own workflow
Powerful community sharing tools
Easier path to contributor to committer
Effective Development with Mylyn, Hudson, Git and Gerrit | © 2011 by Chris Aniszczyk

20. Collaboration
Developers can easily collaborate directly without
needing a central authority or dealing with server
administration costs
Effective Development with Mylyn, Hudson, Git and Gerrit | © 2011 by Chris Aniszczyk

21. Disconnected operations rule!
Developers can still be productive and not worry
about a central server going down... remember the
days of complaining that CVS was down and you
couldn't work?
Also, there's a lighter server
load for administrators!
Effective Development with Mylyn, Hudson, Git and Gerrit | © 2011 by Chris Aniszczyk

22. Branches everywhere
Creating and destroying branches are simple
operations so it's easy to experiment
with new ideas
Very easy to isolate changes
Effective Development with Mylyn, Hudson, Git and Gerrit | © 2011 by Chris Aniszczyk

23. Define your own workflow
Define your own workflow to meet your team needs.
Different workflows can be adopted as your team
grows without changing VCS toolsets!
Effective Development with Mylyn, Hudson, Git and Gerrit | © 2011 by Chris Aniszczyk

24. DVCS and Building Community
Developers can easily discover and fork projects. On
top of that, it's simple for developers to share their
changes
“Distributed version control is all about empowering
your community, and the people who might join your
community” - Mark Shuttleworth
Effective Development with Mylyn, Hudson, Git and Gerrit | © 2011 by Chris Aniszczyk

25. Version Control at Eclipse
Eclipse defined a roadmap to move to Git in 2009
CVS/SVN are deprecated now
Each project is moving to Git on its own timeline...
So why did Eclipse.org choose Git?
Effective Development with Mylyn, Hudson, Git and Gerrit | © 2011 by Chris Aniszczyk

26. #1: Git-related projects at Eclipse.org
… both the core Git library (JGit) and tooling (EGit)
are actively developed at Eclipse.org by a diverse set
of committers and contributors with a common goal
Effective Development with Mylyn, Hudson, Git and Gerrit | © 2011 by Chris Aniszczyk

27. #2: Git is fast
… Git is fast and scales well
*whyisgitbetterthanx.com
Effective Development with Mylyn, Hudson, Git and Gerrit | © 2011 by Chris Aniszczyk

28. #3: Git is mature and popular
… Git is widely used and is the most popular
distributed version control system
Effective Development with Mylyn, Hudson, Git and Gerrit | © 2011 by Chris Aniszczyk

29. #4: Git community tools
… interested in taking advantage of such Git tools
like Gerrit Code Review (used by the Android
community) and GitHub
Effective Development with Mylyn, Hudson, Git and Gerrit | © 2011 by Chris Aniszczyk

30. Eclipse.org: Challenges moving to a DVCS
Convincing management and peers was tough
- At first, everyone is resistant to change
The learning curve of DVCS systems is high
- Initially, the Eclipse tooling was “alpha”
- People refuse to drop to the CLI
Legacy is a pain in the ass!
- 200+ projects at Eclipse used CVS/SVN
- The existing VCS tooling was high quality
Effective Development with Mylyn, Hudson, Git and Gerrit | © 2011 by Chris Aniszczyk

31. No free lunch!
… trust me, the only way to learn DVCS is to start using
it... there is a learning curve, you need to rewire your
brain!
Effective Development with Mylyn, Hudson, Git and Gerrit | © 2011 by Chris Aniszczyk

32. EGit Demo
Effective Development with Mylyn, Hudson, Git and Gerrit | © 2011 by Chris Aniszczyk

33. Agenda
Introduction
Hudson (Jenkins) and Mylyn
Distributed Version Control (DVCS)
Code Review with Git, Gerrit and Mylyn
- What is Code Review?
- Introduction to Gerrit
- Mylyn Reviews Demo (Gerrit)
Conclusion
Q&A
Effective Development with Mylyn, Hudson, Git and Gerrit | © 2011 by Chris Aniszczyk

34. What is Code Review?
When one developer writes code, another developer
is asked to review that code
A careful line-by-line critique
Happens in a non-threatening context
Goal is cooperation, not fault-finding
Often an integral part of coding process
Debugging someone else's broken code
– Involuntary code review: Not so good; emotions may flare
[1] http://code.google.com/p/rietveld/downloads/detail?name=Mondrian2006.pdf
Effective Development with Mylyn, Hudson, Git and Gerrit | © 2011 by Chris Aniszczyk

35. Code Review Benefits
Four eyes catch more bugs
§ Catch bugs early to save hours of debugging
Enforce coding standards
§ Keep overall readability & code quality high
Mentoring of new developers
§ Learn from mistakes without breaking stuff
Establish trust relationships
§ Prepare for more delegation
Good alternative to pair programming
§ asynchronous and across locations
[1] http://code.google.com/p/rietveld/downloads/detail?name=Mondrian2006.pdf
Effective Development with Mylyn, Hudson, Git and Gerrit | © 2011 by Chris Aniszczyk

36. Gerrit Code Review
Gerrit is a Code Review system based on JGit
http://code.google.com/p/gerrit/
Also serves as a git server
adding access control and workflow
Used by
• Android https://review.source.android.com/
• JGit, EGit http://egit.eclipse.org/r/
• Google, Red Hat, SAP, …
Effective Development with Mylyn, Hudson, Git and Gerrit | © 2011 by Chris Aniszczyk

37. History: Google and code review tools
Mondrian (Guido van Rossum)
• based on Perforce, Google infrastructure
• Google proprietary
Rietvield (Guido van Rossum)
• based on Subversion
• Open Source hosted on GoogleApp Engine
Gerrit (Shawn Pearce)
• started as a fork of Rietvield
• based on JGit and GWT
• Open Source (Android)
• Apache 2 license
Effective Development with Mylyn, Hudson, Git and Gerrit | © 2011 by Chris Aniszczyk

38. One Branch One Feature
Master branch contains only reviewed and
approved changes
• master moves from good to better state after
each (approved) change
Each feature branch is based on master branch
• stable starting point
A change can really be abandoned because
• no other approved change can depend on a not
yet approved change
• Gerrit will automatically reject a successor
change of an abandoned change
Effective Development with Mylyn, Hudson, Git and Gerrit | © 2011 by Chris Aniszczyk

39. Gerrit – Lifecycle of a Change
•
create local topic
topic
branch
master
•
commit change
1 •
push it for review
a •
do review
•
automated
verification
Effective Development with Mylyn, Hudson, Git and Gerrit | © 2011 by Chris Aniszczyk

40. Gerrit – Lifecycle of a Change
•
create local topic
topic branch
master
•
commit change
•
push it for review
1 •
do review
•
automated
a
verification
topic master
c
•
refine based on
3 review
•
push new patchsets
b
2 until review votes ok
1 a
Effective Development with Mylyn, Hudson, Git and Gerrit | © 2011 by Chris Aniszczyk

41. Gerrit – Lifecycle of a Change
•
create local topic master
topic branch
master •
commit change
•
push it for review d
topic
1 •
do review
a
•
automated
verification c
3
b
topic master 2
c
•
refine based on a
1
3 review
•
push new patchsets
b until review votes ok
2
•
Submit may lead to
server-side merge
1 a •
or merge / rebase before
push
Effective Development with Mylyn, Hudson, Git and Gerrit | © 2011 by Chris Aniszczyk

42. Gerrit Workflow
Effective Development with Mylyn, Hudson, Git and Gerrit | © 2011 by Chris Aniszczyk

43. Gerrit
Effective Development with Mylyn, Hudson, Git and Gerrit | © 2011 by Chris http://egit.eclipse.org/r/
Aniszczyk - change,825

44. Gerrit and Mylyn Reviews Demo
Effective Development with Mylyn, Hudson, Git and Gerrit | © 2011 by Chris http://egit.eclipse.org/r/
Aniszczyk - change,825

45. Agenda
History of Version Control (VCS)
Hudson (Jenkins) and Mylyn
Distributed Version Control (DVCS)
Code Review with Git and Gerrit
Conclusion
Q&A
Effective Development with Mylyn, Hudson, Git and Gerrit | © 2011 by Chris Aniszczyk

46. Conclusion
The Mylyn project restructuring is a sign of maturity
The future of version control is distributed!
Mylyn Builds works great with Hudson (Jenkins)
Gerrit enables a nice code review workflow
Mylyn Reviews integrates with Gerrit
Developing with Mylyn saves time!
Effective Development with Mylyn, Hudson, Git and Gerrit | © 2011 by Chris Aniszczyk

47. Git Resources
http://git-scm.com/documentation is your friend
Watch Linus' talk at Google
http://www.youtube.com/watch?v=4XpnKHJAok8
Read the Pro Git book - http://progit.org/book/
Effective Development with Mylyn, Hudson, Git and Gerrit | © 2011 by Chris Aniszczyk

48. Q&A
Effective of Version Control in Open Source | © 2010 by Chris Aniszczyk
EvolutionDevelopment with Mylyn, Hudson, Git and Gerrit | © 2011 by Chris Aniszczyk