Git, GitHub, Etc

How git and GitHub work, behind the scenes. Aka what I do in my day job.

Transcript

1. Git, GitHub, Etc
   Andy Delcambre
   

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4. PLANET ARGON
   

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9. DIRECTED
   ACYCLIC
   GRAPH
   

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10. yt $ git init
    Initialized empty Git repository in /private/tmp/demo/.git/
    yt $ echo "My sweet repo" > README
    yt ✗ $ git add README
    yt ✗ $ git status
    # On branch master
    #
    # Initial commit
    #
    # Changes to be committed:
    # (use "git rm --cached ..." to unstage)
    #
    # new file: README
    #
    yt ✗ $ git commit -m "Add a README"
    [master (root-commit) 8a720fa] Add a README
    1 file changed, 1 insertion(+)
    create mode 100644 README
    yt $ git log
    commit 8a720fa06710948f2ab79dd3e213ef745b6000c5
    Author: Andy Delcambre
    Date: Mon Apr 14 15:41:34 2014 -0700
    !
    Add a README
    

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11. 8a720fa
    HEAD, master
    Refs
    Commit
    

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12. yt $ echo "It's so awesome" >> README
    yt ✗ $ git add README
    yt ✗ $ git commit -m "Update README"
    [master ede0fc8] Update README
    1 file changed, 1 insertion(+)
    yt $ git log --graph --decorate --pretty=oneline
    * ede0fc8 (HEAD, master) Update README
    * 8a720fa Add a README%
    

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13. Commit
    8a720fa
    ede0fc8
    HEAD, master
    Refs
    Commit
    

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14. yt $ git cat-file -p ede0fc8
    tree 493fc85c806ebd9e49395561d2f9c98a5d9ebdce
    parent 8a720fa06710948f2ab79dd3e213ef745b6000c5
    author Andy Delcambre 1397516385 -0700
    committer Andy Delcambre 1397516385 -0700
    !
    Update README
    

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15. Commit ede0fc8
    8a720fa
    493fc85
    Parent
    Tree
    

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16. yt $ git cat-file -p 493fc85
    100644 blob 17ca828132ebdc5347f4c5c20484b9a33fffb294 README
    !
    

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17. Tree 493fc85
    17ca828 Blob (README)
    

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18. yt $ git cat-file -p 17ca828
    My sweet repo
    It's so awesome
    

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19. GitHub
    

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20. Secret:
    

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21. Hosting a Git repo is
    Secret:
    

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22. Hosting a Git repo is
    Secret:
    EASY
    

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23. enzo $ git init --bare demo.git
    Initialized empty Git repo in /home/adelcambre/git/demo.git/
    !
    yt $ git remote add origin adelcambre@enzo:git/demo.git
    yt $ git push origin master
    Counting objects: 6, done.
    Delta compression using up to 8 threads.
    Compressing objects: 100% (2/2), done.
    Writing objects: 100% (6/6), 473 bytes, done.
    Total 6 (delta 0), reused 6 (delta 0)
    To adelcambre@enzo:git/demo.git
    * [new branch] master -> master
    !
    yt $ git clone adelcambre@enzo:git/demo.git
    Cloning into 'demo'...
    remote: Counting objects: 6, done.
    remote: Compressing objects: 100% (2/2), done.
    remote: Total 6 (delta 0), reused 0 (delta 0)
    Receiving objects: 100% (6/6), done.
    

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25. yt $ git remote add -f origin git@github.com:adelcambre/demo.git
    Updating origin
    From github.com:adelcambre/demo
    * [new branch] master -> origin/master
    !
    yt $ git push origin master
    Counting objects: 6, done.
    Delta compression using up to 8 threads.
    Compressing objects: 100% (2/2), done.
    Writing objects: 100% (6/6), 473 bytes, done.
    Total 6 (delta 0), reused 6 (delta 0)
    To https://github.com/adelcambre/demo.git
    * [new branch] master -> master
    

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28. GitHub
    Flow
    

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29. Make a branch
    

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30. Add Commits
    

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31. Open a Pull
    Request
    

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32. Discuss &
    Code Review
    

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33. Merge and
    deploy
    

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35. Not so Secret:
    

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36. Hosting a *lot* of Git repos is
    Not so Secret:
    

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37. Hosting a *lot* of Git repos is
    Not so Secret:
    HARD
    

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38. > 7 million
    repositories
    

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39. 1.5 million
    pushes
    

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40. 100 million
    pulls & clones
    

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41. 27
    fileservers
    

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42. 100 TB of
    online storage
    

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44. Grit
    

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45. 1st Commit
    GitHub
    

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46. 1st Commit
    GitHub
    1st Commit
    Grit
    

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47. Ruby
    wrapper around
    Git
    

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48. repo = Grit::Repo.new(“grit.git”)
    !
    repo.commits
    # => [#"e80bbd2ce67651aa18e57fb0b43618ad4baf7750">,
    #"91169e1f5fa4de2eaea3f176461f5dc784796769">,
    #"038af8c329ef7c1bae4568b98bd5c58510465493">,
    #"40d3057d09a7a4d61059bca9dca5ae698de58cbe">,
    #"4ea50f4754937bf19461af58ce3b3d24c77311d9">]
    

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49. This works for
    everything!
    !
    (locally)
    

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50. 27
    fileservers
    

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51. Smoke
    “Grit in the cloud”
    

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52. The
    Internet
    Chimney
    fs102
    fs103
    fs104
    fs105
    …
    fe102
    fe103
    fe104
    fe105
    …
    

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53. The
    Internet
    Chimney
    fs102
    fs103
    fs104
    fs105
    …
    fe102
    fe103
    fe104
    fe105
    …
    

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54. The
    Internet
    Chimney
    fs102
    fs103
    fs104
    fs105
    …
    fe102
    fe103
    fe104
    fe105
    …
    

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55. The
    Internet
    Chimney
    fs102
    fs103
    fs104
    fs105
    …
    fe102
    fe103
    fe104
    fe105
    …
    

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56. The
    Internet
    Chimney
    fs102
    fs103
    fs104
    fs105
    …
    fe102
    fe103
    fe104
    fe105
    …
    BERTRPC
    

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57. module Smoke
    def self.install!
    ::Grit.send(:remove_const,
    :Git)
    !
    ::Grit.const_set(:Git,
    Smoke::Git)
    end
    end
    

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58. repo.ls_tree("HEAD").each do |
    entry|
    if entry.blob?
    repo.load_blob(entry.oid)
    end
    end
    

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59. Death by
    Round Trip
    

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60. A condensed
    (and probably wrong)
    history of git
    

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61. Bitkeeper
    

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62. Git
    

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63. Shared library?
    

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64. libgit2
    

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65. JGit
    

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66. libgit2
    http://github.com/libgit2/libgit2
    

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67. Rugged
    http://github.com/libgit2/rugged
    

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68. Ruby
    wrapper around
    libgit2
    

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69. repo =
    Rugged::Repository.new("rugged.git")
    !
    repo.last_commit
    # => #0277b7df0fea08d5f3fc7177e47527fc24d96a0e>
    

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71. GitRPC
    The New Hotness
    aka
    

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72. Like Smoke,
    But Better
    

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73. Caching
    

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74. Pluggable
    Wire Protocols
    

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75. Encoding
    Aware
    

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76. This is
    My Job
    

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77. education.github.com
    

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78. Questions!
    Git for Computer Scientists
    http://eagain.net/articles/git-for-computer-scientists/
    My mom told me git doesn’t scale
    https://vimeo.com/64716825
    GitHub Flow
    https://guides.github.com/introduction/flow/index.html
    How GitHub uses GitHub to build Github
    http://zachholman.com/talk/how-github-uses-github-to-build-github/
    

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