JAZOON'13 - Stefan Saasen - True Git: The Great Migration

True The great migration

Stefan Saasen

TODO Show of hands

Picture with hands/lighter/concert

Source Control Management

SVN Git


2011 2013 (projected) 2013 2015 (projected)

SVN Git



20

78

SVN Git



20

78

41

68

SVN Git



20

78

41

68

49

70

SVN Git



20

78

41

68

49

70 68

55

SVN Git

Stefan SaasenAtlassian Stash Development Lead

Stefan SaasenAtlassian Stash Development Lead

I come out nice in pictures, I know :-). @stefansaasen

Why am I passionate about this?

Why Git?

Branching & Merging

Branching & Mergingfast, cheap and simple


first class concept


first class concept

Foundation for new workflows

Speed

Speed

git loggit diffgit status

Speed

git bisect


git bisect

Bad

git bisect

Bad

Good (v2.7)

git bisect

Bad

Test

git bisect

Bad

Test

git bisect

Bad

Regression!

git bisect

Regression!

Fast graph traversalFast checkout

git bisect

Speed

git bisect


Enables new features

Improves basic features

Local commits

Local commits

Edit & Publish

Local commitsRewrite History

Edit & Publish

Local commitsRewrite History

Edit & Publish

Flexibility

Git does what you are doing today, only better

S V N

L A B E L T I T L E

GIT

S V N

L A B E L T I T L E

GIT

S V N

Existing workflows

L A B E L T I T L E

GIT

S V N

New ways of collaborating

Existing workflows

L A B E L T I T L E

GIT

S V N


Existing workflows

New branchworkflows

L A B E L T I T L E

GIT

S V N


Existing workflows

New branchworkflows

L A B E L T I T L E

GIT

S V N


Existing workflows

New branchworkflows

L A B E L T I T L E

GIT

S V N


Existing workflows

New branchworkflows

Release branching master

2.8

2.7


2.8

2.7

Bugfix


2.8

2.7

Bugfix


2.8

2.7

Bugfix


2.8

2.7

Bugfix


2.8

2.7

Bugfix

Real World git workflowsS t e f a n S a a s e n

W e d n e s d a y - 1 4 : 0 0

So you’ve decided to migrate!

The process

1

2

3

Inception

Adoption

Conversion

Inception 1

• Is git suitable?

Inception 1


• Test the conversion

Inception 1



• Identify the repositories that need to be converted

Inception 1



• Identify the repositories that need to be converted

• Identify the tools that need to be updated. CI, issue tracking, IDE, scripts and build tools, deployment tools

Inception 1

1

1

2

3

The process

Inception

Adoption

Conversion

Adoption 2

• You need to answer: “What’s in it for me”

Adoption 2


• Make sure tooling is ready and can be used by everyone

Adoption 2



• Identify the git champions - they will be thrilled to help

Adoption 2



• Identify the git champions - they will be thrilled to help

• Don’t expect to win everyone over immediately

Adoption 2

2

Just text by itself, for impact.

2

1

2

3

The process

Inception

Adoption

Conversion

We’ve got you covered!

&Scripts Tutorial & Documentation

We’ve got you covered!

&Scripts Tutorial & Documentation

bit.ly/go-dvcs

http://www.atlassian.com/git

http://www.atlassian.com/git

git-svn

3

3Conversion - Preparation

jdeveloper = John Developer <[email protected]>

Map Authors


mailto:[email protected]


jdeveloper = John Developer <[email protected]>

Map Authors

Identify SVN repository layout

/tags/trunk/branches




git svn clone \ --authors-file=/authors.txt \ --trunk=/trunk \ --tags=/tags \ --branches=/branches

3Conversion - Initial Clone

git svn clone \ --authors-file=/authors.txt \ --trunk=/trunk \ --tags=/tags \ --branches=/branches

3Conversion - Initial Clone

?

3Conversion - Sync

3Conversion - Sync

git svn fetch

3Conversion - Sync

Infrastructure first 3

C I I s s u e s I D E



read-only



read-only



read-only

Sync every minute

• Cleanup branches

• Remove unused files

• Create git tags

• Remove commit metadata

3Conversion - Cleanup

• Cleanup branches

• Remove unused files

• Create git tags

• Remove commit metadata

3Conversion - Cleanup

3


read-only

Then your team 3


read-only

Then your team 3


read-only

Then your team 3


read-only

Other Tools?

SubGit

1

2

3

The process

Inception

Adoption

Conversion

Or are you?

Just text by itself, for impact.

Collaboration model?Branching model?

+

Enterprise

Centralized=+

Enterprise

Centralized=+

Enterprise

Builds

MetricsIssues

Deployments

Workflows will change

Workflows will changefor the better

Workflows will changefor the better

but they don’t have to change on day one!

This happened in both Confluence and JIRA...

master

confluence-project-4.0

CONF-1234

From SVN like

master


CONF-1234

git cherry-pick bae6251

From SVN like

master


CONF-1234

git cherry-pick bae6251

From SVN like

master


CONF-1234

From SVN like

master


CONF-1234

From SVN like

master


To git branch based workflow

master



master


CONF-2345


master


CONF-2345

git merge confluence-project-4.1


master


CONF-2345


master


CONF-2345

git merge confluence-project-4.1


Conclusion

0

20

40

60

80


68

4941

20

55

706878

SVN Git

0

20

40

60

80


68

4941

20

55

706878

SVN Git

Subversion (58%) is being

threatened by Git (47%) for de facto leadership of the Version Control space. Z E R O T U R N A R O U N D D E V E L O P E R P R O D U C T I V I T Y R E P O R T 2 0 1 3

”

“

is here to stay

expands

migration is a solved problem

Thank you for yourattention!

@stefansaasen

[email protected]

www.atlassian.com



http://www.website.com




Image creditshttp://www.flickr.com/photos/marfis75/3272079115/sizes/o/

http://www.flickr.com/photos/al-taqi/4135841914/

http://www.flickr.com/photos/duremi/3200067353/sizes/o/

http://www.flickr.com/photos/marfis75/3272079115/sizes/o/

http://www.flickr.com/photos/marfis75/3272079115/sizes/o/





JAZOON'13 - Stefan Saasen - True Git: The Great Migration

Technology

git tags

git suitable

testbad git

git champions

conversion sync3

release branching master2

sure tooling

new workflows