MidCOM configuration stack

1. Henri Bergius

   MidCOM configuration stack

   Fri July 17 2009 12:15:10 UTC
   Hi, all
   
   Before we slowly start freezing Mjolnir APIs, I'd like to introduce
   another API change to Midgard MVC: configuration stack.
   
   As you know, templating in Mjolnir already follows the stack model,
   meaning that all templates are loaded from a single namespace, with
   components being able to override templates coming from higher levels
   of the stack.
   
   Template stack looks like the following:
   
   * Stacked components (midcom_core etc)
   * Current component
   * Midgard style elements
   * Midgard page elements
   
   This is great as then any component can for instance override the
   error template.
   
   I'd like to do the same for configuration. Currently configuration is
   loaded from stack, but with each component providing its own stack:
   
   * Component config
   * Configuration snippets
   * Page configuration
   
   Instead, I'd make MidCOM configuration service combine all
   configuration into a single stack. This means a loaded component could
   change midcom_core configurations also if they want to.
   Component-specific configs can be handled by having namespaced
   configuration keys (as we do with templates).
   
   In this case, the configuration stack would be:
   
   * Stacked components (midcom_core etc)
   * Current component
   * midgard_config file
   * Configuration snippets
   * Page configuration
   
   This way things dealing with the installation (setting MidCOM cache
   directory for instance) can be loaded from the current midgard_config
   instead of having to edit snippets.
   
   It also means components loaded to the stack can inject their own
   routes into the route definitions. This is very useful as then
   components can add their own administrative UIs easily to the site. In
   current system we do this merge already, but only for routes defined
   by midcom_core and the current component.
   
   --
   Henri Bergius
   Motorcycle Adventures and Free Software
   http://bergie.iki.fi/
   
   Skype: henribergius
   Jabber: henri.bergius@gmail.com
   Microblog: http://www.qaiku.com/home/bergie/
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2. Piotr Pokora

   Re: [midgard-dev] MidCOM configuration stack

   Fri July 17 2009 18:55:07 UTC
   Henri Bergius writes:
   > Hi, all
   
   Hi!
   
   > This way things dealing with the installation (setting MidCOM cache
   > directory for instance) can be loaded from the current midgard_config
   > instead of having to edit snippets.
   
   midgard_config is not propagated from connection, so it's not available
   if implicitly (Apache) initialized.
   We didn't clarify what to do with this issue.
   In this particular environment (Apache) we need to expose sensitive data
   then.
   
   Piotras
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3. Henri Bergius

   Re: [midgard-dev] MidCOM configuration stack

   Sun July 19 2009 13:45:34 UTC
   Hi,
   
   On Fri, Jul 17, 2009 at 9:53 PM, Piotr Pokora<piotrek.pokora@gmail.com> wrote:
   > midgard_config is not propagated from connection, so it's not available
   > if implicitly (Apache) initialized.
   
   Well, that wasn't the core part of the idea of a configuration stack.
   If we can't use midgard_config to this, Midgard MVC can have its own
   file. This might be better anyway as Midgard uses INI syntax and MVC
   uses YAML syntax for configuration.
   
   > Piotras
   
   /Henri
   
   --
   Henri Bergius
   Motorcycle Adventures and Free Software
   http://bergie.iki.fi/
   
   Skype: henribergius
   Jabber: henri.bergius@gmail.com
   Microblog: http://www.qaiku.com/home/bergie/
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4. Henri Bergius

   Re: MidCOM configuration stack

   Mon November 30 2009 18:17:39 UTC

   Hi,

   I'd make MidCOM configuration service combine all configuration into a single stack. This means a loaded component could change midcom_core configurations also if they want to.

   This is now done: http://trac.midgard-project.org/changeset/24261

   A lot cleaner API, better injection support, and about 10% performance improvement (which will be easy to beat by adding config cache, the array merges we do there are expensive).

   /Henri

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