AsseticBundle Configuration - Explaination - symfony

Question

there is no real detail in the documentation about the AsseticBundle Config - in config.yml.
assetic:
debug: "%kernel.debug%"
use_controller:
enabled: "%kernel.debug%"
profiler: false
read_from: "%kernel.root_dir%/../web"
write_to: "%assetic.read_from%"
java: /usr/bin/java
node: /usr/bin/node
ruby: /usr/bin/ruby
sass: /usr/bin/sass
# An key-value pair of any number of named elements
variables:
some_name: []
bundles:
# Defaults (all currently registered bundles):
- FrameworkBundle
- SecurityBundle
- TwigBundle
- MonologBundle
- SwiftmailerBundle
- DoctrineBundle
- AsseticBundle
- ...
assets:
# An array of named assets (e.g. some_asset, some_other_asset)
some_asset:
inputs: []
filters: []
options:
# A key-value array of options and values
some_option_name: []
filters:
# An array of named filters (e.g. some_filter, some_other_filter)
some_filter: []
workers:
# see https://github.com/symfony/AsseticBundle/pull/119
# Cache can also be busted via the framework.templating.assets_version
# setting - see the "framework" configuration section
cache_busting:
enabled: false
twig:
functions:
# An array of named functions (e.g. some_function, some_other_function)
some_function: []
I'm specially interested in
read_from: don't understand the path, too
write_to:
because I don't really understand how to use it.
So, I want to use SCSS and Compass and I have an folder in AppBundle/Resources/assets/styles/main.scss
What I have to setup in the config.yml, that assetic know how he find the main.scss as a global setting?

Answer 1

Unless you are trying to update the directory from which Assetic reads/writes (thus being /web by default), you don't need to change anything here. The configuration can be understood from a good part on the Symfony documentation. You'll find what you need in:
read_from: "%kernel.root_dir%/../web"
write_to: "%assetic.read_from%"
These are paths to a directory which is writable/readable, and exposed to the public. In this case, it means it will look for /path/to/app/../web for both readings and writings.
In a general manner, check for php app/console config:dump-reference X to find the default configuration of a given bundle, where X is the bundle config name. In your case, try the later: php app/console config:dump-reference assetic
Now, what you want is to use compass/sass from your view as far as I can see.
In your twig file, put the following:
{% stylesheets 'path/to/main.scss' filter='compass' %}
<link rel="stylesheet" type="text/css" href="{{ asset_url }}">
{% endstylesheets %}
After adding the configuration for compass if it needs to be tweaked, you should be all set.
Is it helping? it not, could you please provide more details?