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/docs/disabling-sites.txt

https://bitbucket.org/ianb/silverlining/
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Possible License(s): GPL-2.0 
    

  1. .. -*- mode: rst -*-
    2. 

  2. 

  3. =================
    4. 

  4.  Disabling Sites
    5. 

  5. =================
    6. 

  6. 

  7. When hosting a site it's likely that from time to time it will be
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  8. necessary to make it unavailable to the general public while some
    9. 

  9. maintenance is carried out.  Silver Lining provides a mechanism for
    10. 

  10. allowing this.  It is important to recognise that it is *applications*
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  11. that are disabled via this mechanism, rather than locations, so if the
    12. 

  12. same application is accessible via two different locations (even if it
    13. 

  13. is two different *deployments* of the application), and it is
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  14. disabled, then it will appear to be disabled at both locations.  This
    15. 

  15. is because if your application uses a database, then all different
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  16. deployments of the application will share the database, and cleaning
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  17. up databases is one of the key use-cases for this feature.
    18. 

  18. 

  19. Disabling an application
    20. 

  20. ========================
    21. 

  21. 

  22. The following command will disable an application called blog::
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  23. 

  24.     $ silver disable --by-name blog
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  25. 

  26. You can also disable the application by giving a path that it appears
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  27. at::
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  28. 

  29.     silver disable --by-location www.example.com/blog
    30. 

  30. 

  31. Enabling an application
    32. 

  32. =======================
    33. 

  33. 

  34. To re-enable an application you use the ``silver enable`` command,
    35. 

  35. which takes the same options as silver disable command.
    36. 

  36. 

  37. The disabled special location
    38. 

  38. =============================
    39. 

  39. When an application is disabled, visitors to it will be shown a page
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  40. explaining that the site is unavailable (similarly there is a
    41. 

  41. not-found location which is shown when a URL is not resolved).  It is
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  42. possible to replace this page by uploading a new WSGI application to
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  43. the special location "disabled".  To restore the default application,
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  44. use the ``silver activate`` command to point the disabled location to
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  45. "default-disabled".
    46. 

  46. 

  47. Headers for disabled apps
    48. 

  48. -------------------------
    49. 

  49. It is sensible to return a "503 Service Unavailable" response from a
    50. 

  50. disabled app and use the following headers:
    51. 

  51. 

  52. :Cache-Control: no-store, no-cache, max-age=0
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  53. :Pragma: no-cache
    54. 

  54. 

  55. Access To disabled apps
    56. 

  56. =======================
    57. 

  57. While an application is disabled, it is still possible to access it
    58. 

  58. via the command line tools.  ``silver backup``, ``restore``, ``run``
    59. 

  59. etc. will all work as usual.  It's also possible to access the site
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  60. through a web browser.  At present the application is only made
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  61. available to clients connecting from localhost, so to view the site
    62. 

  62. and access management facilities you will probably need to set up an
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  63. SSH tunnel and manually update ``/etc/hosts`` on your own machine.
    64. 

  64.