Migrating from Subversion to Git and GitHub

Git is a compelling version control system, but it is useful to talk about it in the context of a destination, made possible by migration tools from previous version control systems like Subversion. This talk offers a set of motivations, tools, and techniques on the Subversion to Git and GitHub migration process.

Transcript

1. VERSION CONTROL REINVIGORATED from Subversion to Git and GitHub
2. VERSION CONTROL REINVIGORATED from Subversion to Git and GitHub from Subversion to Git and GitHub
3. @matthewmccull matthew@github.com github.com/training
4. Who is Matthew? Open source contributor Build tool and continuous delivery author 5 year Git evangelist VP of Training at GitHub
5. The Change
6. SVN ‛ GIT
10. — Every manager, ever If it isn't broke, don't fix it.
11. The Radar
14. July 2011 Technology Radar Prepared by the ThoughtWorks Technology Advisory Board http://www.thoughtworks.com/radar
15. July 2011 Technology Radar Prepared by the ThoughtWorks Technology Advisory Board http://www.thoughtworks.com/radar Tools 30. Subversion 31. Git 32. Infrastructure as code 33. Github 34. Caching reverse proxies 35. Splunk 36. Mercurial 37. Message buses without smarts 38. NoSQL 39. Next gen test tools 40. New Relic beyond Rails 41. TLB 42. Powershell 43. Selenium 2 testing of mobile websites 44. Deltacloud 45. Vagrant 46. API management services 47. jQuery Mobile 48. Backbone.js 49. Sonar 50. Open source bI tools 51. Gradle 52. Cross platform mobile toolkits 53. ESB 54. VCS with “implicit workflow” 55. Code in configuration 26 16 13 22 12 5 3 32 36 46 53 45 44 37 39 35 38 30 4 6 56 76 69 58 57 7 15 14 25 29 28 27 21 23 17 19 24 18 20 11 9 2 10 31 33 42 41 40 50 47 48 49 51 54 43 55 52 34 1 8 New or Moved No change Techniques 1. Progressive enhancement 2. Automate database deployment 3. Platform roadmaps 4. Evolutionary database 5. Emergent design 6. Visualization and metrics 7. Coding architects 8. Evolutionary architecture 9. DevOps 10. Simple performance trending 11. Continuous delivery 12. Concurrency abstractions and patterns 13. Acceptance test of journeys 14. Categorization & prioritization of technical debt 15. Continuous deployment 16. Capability modeling 17. Thoughtful caching 18. Iterative data warehousing 19. Build your own radar 20. Event API’s 21. Event driven business intelligence 22. Smart systems 23. Event sourcing 24. Decision driven BI 25. Scrum certification 26. Database based integration 27. Procedure oriented integration 28. Feature branching 29. Manual infrastructure management
16. Tools 30. Subversion 31. Git 32. Infrastructure as code 33. Github 34. Caching reverse proxies 35. Splunk 36. Mercurial 37. Message buses without smarts 38. NoSQL 39. Next gen test tools 40. New Relic beyond Rails 41. TLB 42. Powershell 43. Selenium 2 testing of mobile websites 44. Deltacloud 45. Vagrant 46. API management services 47. jQuery Mobile 48. Backbone.js 49. Sonar 50. Open source bI tools 51. Gradle 52. Cross platform mobile toolkits 53. ESB 54. VCS with “implicit workflow” 55. Code in configuration 26 16 13 22 12 5 3 32 36 46 53 45 44 37 39 35 38 30 4 6 7 15 14 25 29 28 27 21 23 17 19 24 18 20 11 9 2 10 31 33 42 41 40 50 47 48 49 51 54 43 55 52 34 1 8 New or Moved No change Techniques 1. Progressive enhancement 2. Automate database deployment 3. Platform roadmaps 4. Evolutionary database 5. Emergent design 6. Visualization and metrics 7. Coding architects 8. Evolutionary architecture 9. DevOps 10. Simple performance trending 11. Continuous delivery 12. Concurrency abstractions and patterns 13. Acceptance test of journeys 14. Categorization & prioritization of technical debt 15. Continuous deployment 16. Capability modeling 17. Thoughtful caching 18. Iterative data warehousing 19. Build your own radar 20. Event API’s 21. Event driven business intelligence 22. Smart systems 23. Event sourcing 24. Decision driven BI 25. Scrum certification 26. Database based integration 27. Procedure oriented integration 28. Feature branching 29. Manual infrastructure management
17. Tools 30. Subversion 31. Git 32. Infrastructure as code 33. Github 34. Caching reverse proxies 35. Splunk 36. Mercurial 37. Message buses without smarts 38. NoSQL 39. Next gen test tools 40. New Relic beyond Rails 41. TLB 42. Powershell 43. Selenium 2 testing of mobile websites 44. Deltacloud 45. Vagrant 46. API management services 47. jQuery Mobile 48. Backbone.js 49. Sonar 50. Open source bI tools 51. Gradle 52. Cross platform mobile toolkits 53. ESB 54. VCS with “implicit workflow” 55. Code in configuration 26 16 13 22 12 5 3 32 36 46 53 45 44 37 39 35 38 30 4 6 7 15 14 25 29 28 27 21 23 17 19 24 18 20 11 9 2 10 31 33 42 41 40 50 47 48 49 51 54 43 55 52 34 1 8 New or Moved No change Techniques 1. Progressive enhancement 2. Automate database deployment 3. Platform roadmaps 4. Evolutionary database 5. Emergent design 6. Visualization and metrics 7. Coding architects 8. Evolutionary architecture 9. DevOps 10. Simple performance trending 11. Continuous delivery 12. Concurrency abstractions and patterns 13. Acceptance test of journeys 14. Categorization & prioritization of technical debt 15. Continuous deployment 16. Capability modeling 17. Thoughtful caching 18. Iterative data warehousing 19. Build your own radar 20. Event API’s 21. Event driven business intelligence 22. Smart systems 23. Event sourcing 24. Decision driven BI 25. Scrum certification 26. Database based integration 27. Procedure oriented integration 28. Feature branching 29. Manual infrastructure management
18. 26 16 13 22 12 5 3 32 36 46 53 45 44 37 39 35 38 30 4 6 56 74 76 69 58 57 7 15 14 25 29 28 27 21 23 17 19 24 18 20 11 9 2 10 80 75 60 31 33 42 41 40 50 47 48 49 51 54 43 55 52 34 1 8 Ne No ation & prioritization cal debt us deployment y modeling ul caching data warehousing
19. Migration Tools
20. git-svn
21. git-svn Core Git feature
22. $ git svn clone -s http://yourhost.com/reporoot/
23. git-svn Consumes an authors email mapping file
24. (no author) = Codehaus infra <support@codehaus.org> sdevijver = Steven Devijver <support@codehaus.org> markcc = Mark CC <support@codehaus.org> joe = Joe <support@codehaus.org> ajtarter = Aaron J Tarter <support@codehaus.org> liddon = Lidia Donajczyk-Lipinska <support@codehaus.org> jshickey = Scott Hickey <jshickey@yahoo.com> HamletDRC = Hamlet D'Arcy <hamletdrc@gmail.com> aalmiray = Andres Almiray <aalmiray@gmail.com> blackdrag = Jochen Theodorou <blackdrag@gmx.org> bob = Boc McWhirter <bob@codehaus.org> brownj = Jeff Brown <jeff@jeffandbetsy.net> cstein = Christian Stein <sormuras@gmx.de>
25. git-svn Migrates Subversion tags to Git branches
26. svn2git
28. $ svn2git http://matthew.com/svnrepos/project1
29. importing to git
31. # Publish one branch $ svn2git http://matthew.com/svnrepos/project1 $ git remote add origin https://github.com/you/project1 $ git push origin master
32. # Publish all branches and tags $ svn2git http://matthew.com/svnrepos/svnproject1 $ git clone file://yourpath/svnproject1 gitproject1 $ cd gitproject1 $ git remote add origin https://github.com/you/project1 $ git push --mirror origin
33. Serving SVN from Git
35. $ svn co https://github.com/you/project1/trunk p1svn
36. Data Structures
37. — No engineer, ever Wow! Version control!
38. DAG
39. v1 v2 v3 v4 File A File B File C File A File B File B File C v5 File A File B File B
40. v1 v2 v3 v4 File A File B File C File A File B File B File C v5 File A File B File B Δ Δ Δ Δ Δ Δ Δ
42. Checkin Checkin Checkin Checkin Checkin Checkin Checkin Checkin Checkin Checkin Checkin Delta storage gets slower as the history of a file gets longer
44. Copy of the entire tree per commit
45. Why?
46. v1 v2 v3 v4 File A File B File C File A File B File B File C v5 File A File B File B File A File A File C File C File C
47. v1 v2 v3 v4 File A File B File C File A File B File B File C v5 File A File B File B File A File A File C File C File C
48. hard link to existing identical blobs
49. v1 v2 v3 v4 File A File B File C File A File B File B File C v5 File A File B File B File A File A File C File C File C
50. v1 v2 v3 v4 File A File B File C File A File B File B File C v5 File A File B File B File A File A File C File C File C ß
51. zlib deflates each blob at commit
52. v1 v2 v3 v4 File A File B File C File A File B File B File C v5 File A File B File B File A File A File C File C File C
53. v1 v2 v3 v4 File A File B File C File A File B File B File C v5 File A File B File B File A File A File C File C File C
54. zlib deflates the entire repo
55. v1 v2 v3 v4 File A File B File C File A File B File B File C v5 File A File B File B File A File A File C File C File C
56. v1 v2 v3 v4 File A File B File C File A File B File B File C v5 File A File B File B File A File A File C File C File C
57. Act I 2100 MB became 205 MB
58. refs
59. centralized VCSs use sequential revision numbers
60. Git uses a SHA-1 hash
62. 40 hex characters (20 bytes)
63. 9AB223D28B1AA46EF1780B22F304982E39872C34
64. 9AB223D28B1AA46EF1780B22F304982E39872C34 <html> <body> <p>This is a test</p> <img src="http://ai.com/icon.gif"> </body> </html>
65. <html> <body> <p>This is a test</p> <img src="http://ai.com/icon.gif"> </body> </html> 9AB223D28B1AA46EF1780B22F304982E39872C34
66. ‣Blob ‣Tree ‣Commit ‣Tag
67. tree tree: 7e8b1 web blob: 9ab16 index.html a10b3 tree blob: 8d162 logo.jpg blob: 51d22 draw.js 7e8b1 commit tree: a10b3 parent: nil author: Fird committer: Matthew message: Major refactoring of the web content. c67db blob <html> <body></body> </html> 9ab16 blob //Some more javascript var renderSize 51d22 blob 7D 8D B3 7F BD 12 9F E9 7B 78 9D 3F 5C A6 72 CB 8d162
68. tree tree: 7e8b1 web blob: 9ab16 index.html a10b3 tree blob: 8d162 logo.jpg blob: 51d22 draw.js 7e8b1 commit tree: a10b3 parent: nil author: Fird committer: Matthew message: Major refactoring of the web content. c67db blob <html> <body></body> </html> 9ab16 blob //Some more javascript var renderSize 51d22 blob 7D 8D B3 7F BD 12 9F E9 7B 78 9D 3F 5C A6 72 CB 8d162
69. tree tree: 7e8b1 web blob: 9ab16 index.html a10b3 tree blob: 8d162 logo.jpg blob: 51d22 draw.js 7e8b1 commit tree: a10b3 parent: nil author: Fird committer: Matthew message: Major refactoring of the web content. c67db blob <html> <body></body> </html> 9ab16 blob //Some more javascript var renderSize 51d22 blob 7D 8D B3 7F BD 12 9F E9 7B 78 9D 3F 5C A6 72 CB 8d162
70. tree tree: 7e8b1 web blob: 9ab16 index.html a10b3 tree blob: 8d162 logo.jpg blob: 51d22 draw.js 7e8b1 commit tree: a10b3 parent: nil author: Fird committer: Matthew message: Major refactoring of the web content. c67db blob <html> <body></body> </html> 9ab16 blob //Some more javascript var renderSize 51d22 blob 7D 8D B3 7F BD 12 9F E9 7B 78 9D 3F 5C A6 72 CB 8d162
71. tree tree: 7e8b1 web blob: 9ab16 index.html a10b3 tree blob: 8d162 logo.jpg blob: 51d22 draw.js 7e8b1 commit tree: a10b3 parent: nil author: Fird committer: Matthew message: Major refactoring of the web content. c67db blob <html> <body></body> </html> 9ab16 blob //Some more javascript var renderSize 51d22 blob 7D 8D B3 7F BD 12 9F E9 7B 78 9D 3F 5C A6 72 CB 8d162
72. tree tree: 7e8b1 web blob: 9ab16 index.html a10b3 tree blob: 8d162 logo.jpg blob: 51d22 draw.js 7e8b1 commit tree: a10b3 parent: nil author: Fird committer: Matthew message: Major refactoring of the web content. c67db blob <html> <body></body> </html> 9ab16 blob //Some more javascript var renderSize 51d22 blob 7D 8D B3 7F BD 12 9F E9 7B 78 9D 3F 5C A6 72 CB 8d162
73. tree tree: 7e8b1 web blob: 9ab16 index.html a10b3 tree blob: 8d162 logo.jpg blob: 51d22 draw.js 7e8b1 commit tree: a10b3 parent: nil author: Fird committer: Matthew message: Major refactoring of the web content. c67db blob <html> <body></body> </html> 9ab16 blob //Some more javascript var renderSize 51d22 blob 7D 8D B3 7F BD 12 9F E9 7B 78 9D 3F 5C A6 72 CB 8d162
74. tree tree: 7e8b1 web blob: 9ab16 index.html a10b3 tree blob: 8d162 logo.jpg blob: 51d22 draw.js 7e8b1 commit tree: a10b3 parent: nil author: Fird committer: Matthew message: Major refactoring of the web content. c67db blob <html> <body></body> </html> 9ab16 blob //Some more javascript var renderSize 51d22 blob 7D 8D B3 7F BD 12 9F E9 7B 78 9D 3F 5C A6 72 CB 8d162
75. tree tree: 7e8b1 web blob: 9ab16 index.html a10b3 tree blob: 8d162 logo.jpg blob: 51d22 draw.js 7e8b1 commit tree: a10b3 parent: nil author: Fird committer: Matthew message: Major refactoring of the web content. c67db blob <html> <body></body> </html> 9ab16 blob //Some more javascript var renderSize 51d22 blob 7D 8D B3 7F BD 12 9F E9 7B 78 9D 3F 5C A6 72 CB 8d162
76. v1 v2 v3 commit tree: 9a87b parent: nil author: Fird committer: Matthew message: Major refactoring of the Javascript rendering engine. c67db commit tree: b22c1 parent: c67db author: Tim committer: Fird message: Minor update to HTML 9bd21 commit tree: b22c1 parent: 9bd21 author: Johnny committer: Joe message: New language transations 1c2d7
77. v1 v2 v3 commit tree: 9a87b parent: nil author: Fird committer: Matthew message: Major refactoring of the Javascript rendering engine. c67db commit tree: b22c1 parent: c67db author: Tim committer: Fird message: Minor update to HTML 9bd21 commit tree: b22c1 parent: 9bd21 author: Johnny committer: Joe message: New language transations 1c2d7
78. v1 v2 v3 commit tree: 9a87b parent: nil author: Fird committer: Matthew message: Major refactoring of the Javascript rendering engine. c67db commit tree: b22c1 parent: c67db author: Tim committer: Fird message: Minor update to HTML 9bd21 commit tree: b22c1 parent: 9bd21 author: Johnny committer: Joe message: New language transations 1c2d7
79. v1 v2 v3 commit tree: 9a87b parent: nil author: Fird committer: Matthew message: Major refactoring of the Javascript rendering engine. c67db commit tree: b22c1 parent: c67db author: Tim committer: Fird message: Minor update to HTML 9bd21 commit tree: b22c1 parent: 9bd21 author: Johnny committer: Joe message: New language transations 1c2d7
80. v1 v2 v3 commit tree: 9a87b parent: nil author: Fird committer: Matthew message: Major refactoring of the Javascript rendering engine. c67db commit tree: b22c1 parent: c67db author: Tim committer: Fird message: Minor update to HTML 9bd21 commit tree: b22c1 parent: 9bd21 author: Johnny committer: Joe message: New language transations 1c2d7
81. v1 v2 v3 commit tree: 9a87b parent: nil author: Fird committer: Matthew message: Major refactoring of the Javascript rendering engine. c67db commit tree: b22c1 parent: c67db author: Tim committer: Fird message: Minor update to HTML 9bd21 commit tree: b22c1 parent: 9bd21 author: Johnny committer: Joe message: New language transations 1c2d7
82. v1 v2 v3 commit tree: 9a87b parent: nil author: Fird committer: Matthew message: Major refactoring of the Javascript rendering engine. c67db commit tree: b22c1 parent: c67db author: Tim committer: Fird message: Minor update to HTML 9bd21 commit tree: b22c1 parent: 9bd21 author: Johnny committer: Joe message: New language transations 1c2d7
83. v1 v2 v3 commit tree: 9a87b parent: nil author: Fird committer: Matthew message: Major refactoring of the Javascript rendering engine. c67db commit tree: b22c1 parent: c67db author: Tim committer: Fird message: Minor update to HTML 9bd21 commit tree: b22c1 parent: 9bd21 author: Johnny committer: Joe message: New language transations 1c2d7
84. RELEASE_1.0 HEAD bug979branch commit c67db commit 9bd21 commit 1c2d7 commit 8c2d1 commit 1bdcd commit 2daa1
85. RELEASE_1.0 HEAD bug979branch commit c67db commit 9bd21 commit 1c2d7 commit 8c2d1 commit 1bdcd commit 2daa1
86. RELEASE_1.0 HEAD bug979branch commit c67db commit 9bd21 commit 1c2d7 commit 8c2d1 commit 1bdcd commit 2daa1
87. RELEASE_1.0 HEAD bug979branch commit c67db commit 9bd21 commit 1c2d7 commit 8c2d1 commit 1bdcd commit 2daa1
88. RELEASE_1.0 HEAD bug979branch commit c67db commit 9bd21 commit 1c2d7 commit 8c2d1 commit 1bdcd commit 2daa1
89. RELEASE_1.0 HEAD bug979branch commit c67db commit 9bd21 commit 1c2d7 commit 8c2d1 commit 1bdcd commit 2daa1
90. Git Highlights
91. Local commits
92. Content Tracking
93. simpler Merges
94. Start now
95. git-svn conversion to Git git-svn bridge to SVN GitHub SVN URLs Conversion Options
97. Thanks!
98. @matthewmccull matthew@github.com github.com/training