Managing CPAN dependencies with Carton

at Nordic Perl Workshop 2013

Transcript

1. Carton
   managing CPAN dependencies
   Tatsuhiko Miyagawa
   @miyagawa
   Nordic Perl Workshop 2013
   Saturday, November 23, 13
   

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2. Me
   • Tatsuhiko Miyagawa
   • Lives in San Francisco
   • {github,twitter,CPAN}/miyagawa
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3. Thank You!
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4. Managing CPAN
   Dependencies
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5. How many CPAN modules
   your app depends on?
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6. When is the last time
   upgrading a CPAN
   module broke your app?
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7. Case Study:
   Web App Development
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8. You’re writing a new web app
   using as many CPAN modules.
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9. Get them from CPAN,
   install on your machine.
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10. john@local>  cpanm  Web::Framework
    installed  LWP-­‐5.912
    installed  Plack-­‐0.9980
    installed  Web-­‐Framework-­‐1.10
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11. Test it...
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12. Works? Ship it!
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13. What if ...
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14. • Jul 2nd: Started working on project
    • using Web::Framework 1.1
    • Jul 9th: Finished version 1.0
    • Jul 10-15th: internal beta, QA
    • Jul 16th: Deploy to the production
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15. • Jul 2nd: Started working on project
    • using Web::Framework 1.1
    • Jul 9th: Finished version 1.0
    • Jul 10-15th: internal beta, QA
    • Jul 15th: Web::Framework 1.2 is released
    • Jul 16th: Deploy to the cloud/production
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16. root@prod>  cpanm  Web::Framework
    installed  LWP-­‐5.912
    installed  Plack-­‐0.9980
    installed  Web-­‐Framework-­‐1.20
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17. Web::Framework 1.2
    API changes!
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18. Saturday, November 23, 13
    

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19. Saturday, November 23, 13
    

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20. “Upgrading CPAN modules
    broke my app”
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21. Dependencies are
    part of your app.
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22. a solution
    cpanm 1.6
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23. >  cpanm  Web::Framework@1.10
    installed  Web-­‐Framework-­‐1.10
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24. >  cpanm  Web::Framework~">=  1.0,  <  1.2"
    installed  Web-­‐Framework-­‐1.19
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25. ♥ MetaCPAN
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26. a solution
    cpanfile + cpanm 1.6
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27. >  cat  cpanfile
    requires  'Web::Framework',  '==  1.10';
    >  cpanm  -­‐-­‐installdeps  .
    installed  Web-­‐Framework-­‐1.10
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28. cpanfile
    DSL to describe prereqs
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29. requires  'Catalyst',  '5.8000';  
    recommends  'JSON::XS',  '2.0';
    on  'test'  =>  sub  {
       requires  'Test::More',  '>=  0.96'
    };
    on  'develop'  =>  sub  {
       recommends  'Devel::NYTProf';
    };
    feature  'sqlite'  =>  sub  {
       requires  'DBD::SQLite';
    };
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30. inspired by:
    gemfile(5)
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31. Compatible to:
    Module::Install(::DSL)
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32. Converted to:
    CPAN::Meta::Prereqs
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33. Toolset
    Module::CPANfile
    Module::Install::CPANfile
    Dist::Zilla plugins
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34. Supported by
    dzil, Milla & cpanm 1.6
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35. cpanfile + cpanm
    • Simple
    • Yet powerful and flexible way to describe
    dependencies and version requirements
    • Version control cpanfile
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36. caveats
    • Locking each dependency with specific
    version is tedious work
    • Can only lock direct dependencies
    • MetaCPAN as SPOF
    • No easy/reliable way to fallback
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37. Many other solutions
    Needs servers, Needs databases
    Too simple, Too complicated, etc.
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38. the new Solution
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39. Carton
    https://github.com/miyagawa/carton
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40. Inspired by...
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41. Saturday, November 23, 13
    

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42. Basic idea:
    Describe CPAN dependencies
    snapshot tarball pathnames
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43. Built on top of:
    cpanfile + cpanm 1.7
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44. • App-specific local environment
    • Fast and safe install with caches
    • Dep-tree analysis, including versions
    • Freezing module versions
    • Conservative updates
    • Easy Redeployment, Rollback
    • Single-file, VCS friendly
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45. Local perl environment
    Using local::lib and cpanm -L
    Each app has an isolated local library path
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46. Fast and safe install
    Saves MYMETA.json and install meta info
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47. Dep tree analysis
    Rebuild the dependency tree from snapshot
    Checks if anything is missing/superfluous
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48. Freezing versions
    Versions are saved in snapshots
    including dependencies
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49. Easy Redeployment
    Reinstall exactly the same set of modules
    on another prod/development machines.
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50. Conservative Update
    Modules won't be upgraded
    unless it is required, or manually updated.
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51. Single-file, VCS friendly
    You can add cpanfile.snapshot to git
    update whenever you update modules
    "Dependencies are part of your app."
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52. Safe and easy rollback
    revert the lock file and redeploy
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53. DEMO
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54. Deployment
    with Carton
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55.  @local>  carton  install
     @local>  git  commit  cpanfile.snapshot
     @local>  git  push
    @remote>  carton  install  -­‐-­‐deployment
    @remote>  carton  exec  plackup  ...
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56. Example:
    github.com/miyagawa/cpanmetadb-perl
    capistrano, Server::Starter,
    carton, plackup (twiggy)
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57. PaaS/Cloud
    github.com/miyagawa/heroku-buildpack-perl
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58. Saturday, November 23, 13
    

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59. http://weblog.bulknews.net
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60. Support to come!
    Dokku, DotCloud, Travis CI,
    Cloud Foundry etc.
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61. carton 1.0
    on CPAN
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62. >  cpanm  Carton
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63. Preview:
    next major releases
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64. cpanm 1.8
    git (+ any URL)
    support in index
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65. cpanfile 1.1
    git syntax support
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66. requires  'Plack',  '1.0000',
       git  =>  'git://github.com/plack/Plack.git',
       ref  =>  'devel';
    carton 1.1
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67. requires  'Plack',  '1.0011',
       dist  =>  'MIYAGAWA/Plack-­‐1.0011.tar.gz';
    carton 1.1
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68. requires  'Plack',  '1.0011',
       dist  =>  'http://darkpan/Plack-­‐1.tar.gz';
    carton 1.1
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69. (demo)
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70. cpanm 1.8
    • Rewrite internals
    • Backend API
    • Plugin support
    • CPAN Testers support (via plugins)
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71. carton 1.1
    • binstubs
    • configure args/hints support
    • safe exec on development
    • remember options (--path etc.)
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72. github.com/miyagawa/carton
    irc.perl.org #carton
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73. speakerdeck.com
    /miyagawa
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74. gum.co/BmXz
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75. Questions?
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