lib_config Documentation

Bundles

lib_config supports Rock's bundle mechanisms. A Bundle is a predefined folder structure, where a certain places specific information s supposed to be found.

Following the folder structure as expectd from lib_config is documented. Thereby all folders are give relative to the root folder of a bundle:

config/orogen

YAML-like files containing configuration properties for components of a certain prototype. The name of a file within the folder has to correspond with the name of the prototype it contains the configuration properties for.

Example: The file config/orogen/joint_dispatcher::Task.yml contains the properties for the Rock-Task joint:dispatcher::Task.

data

Directory used for not further specified data.

TODO: Clarify if and where in the code this folder is used and evaulate the reason.

logs

The data logger per default outputs its log files to this folder. lib_config provides an API function Bundle::createLogDirectory() that creates a new log directory in the logs folder using the following pattern: logs/%Y%m%d-%H%M.

If the function is called multiple times within the same minute, the name gets extended with a suffix: logs/%Y%m%d-%H%M.i, where i is incremented.

logs/current

When the API function Bundle::createLogDirectory() is called (see logs), a symlink called logs/current is created that points to the folder that has just been created. Thus the symlink should always point to the most recently created log folder.

Configuration

Configuration files

config/bundle.yml

This files YAML contains the configration properties of a bundle in form of a map called bundle. The following properties are supported:

• dependencies: A list of bundle names containing data that is required for the present bundle to work.

Example:

# Bundle-specific configuration
bundle:
    # List of bundles we depend on
    dependencies:
        - other_bundle
        - yet_another_bundle

If the file is not present, it is assumed, that the bundle depends on no other bundles.

We have a breadth-first discovery behaviour of dependencies. This means that first level dependecies are considered more relvant than second level dependencies.

Example: This dependency tree

     bundle_1
       |- bundle_2
            |- bundle_4
       |- bundle_3

is resolved to this priorization:

      1. bundle_1
      2. bundle_2
      3. bundle_3
      4. bundle_4

Environment Variables

The following environment Variables are used

ROCK_BUNDLE

Configures the currently selected bundle. lib_config allos to specify the bundle either by its name (i.e. folder-name of the Bundle visible within ROCK_BUNDLE_PATH) or absolute path.

Example: Both examples

ROCK_BUNDLE_PATH=/home/malte/rock/bundles
ROCK_BUNDLE=my_bundle

and

ROCK_BUNDLE=/home/malte/rock/bundles/my_bundle

refer to the same bundle at /home/malte/rock/bundles/my_bundle for lib_config.

ROCK_BUNDLE_PATH

Defines a set of absolute folder-paths which are searched for bundles. Multiple paths are separated by thhe :-symbol.

Example:

ROCK_BUNDLE_PATH=/home/malte/rock/bundles:/home/malte/rock/other_bundles