Overview¶

Configuration Tree Description¶

Configuration hierarchy is to be described in a cfgtree.ConfigBaseModel inherited instance, inside the member .model, using helper classes such as StringCfg, IntCfg, IPCfg or PasswordCfg. Each setting can be set by environment variable, command line parameter or by the storage file(s) itself.

Let’s take an example of an item defined at the first level of the hierarchy. It is defined as a IntCfg with name count. User can set this setting by:

environment variable APPLICATIONNAME_COUNT (where APPLICATIONNAME is an optional, developer-defined prefix added to every environment variable of the application to avoid conflicts)
command line argument --count
item count at the first level of a json file

Hierarchical structure is reflected in these different ways, to avoid conflicts. Now, let’s imagine the ‘count’ setting is set in a group called ‘general’:

environment variable is: APPLICATIONNAME_GENERAL_COUNT
command line argument is: --general-count
Json has a first level named general, and inside one of the items is called count:
```
{
    "general": {
        "count": 1
    }
}
```

Configuration Storage¶

The trivial storage is a simple json file. The complete settings are placed inside it, such as:

{
    "group1": {
        "string_opt": "a string",
        "int_opt": 123,
        "float_opt": 2.0,
        "bool_opt": true
    }
}

cfgtree allows complete customization of the file storage, developers can even develop their own.

Current Support:

single Json file
Anyconfig supported file type (yaml, toml, json,…)

Future support:

Multiple file example
Configuration server

Access to settings¶

In your application, an xpath-like syntax allows you to reach any item of the configuration, using a xpath-like syntax <key1>.<key2>.<key3>.<item>, for example:

cfg = AnyConfigModel(model={
    "group1": {
        "string_opt": StringCfg(
            short_param='-s',
            long_param="--string-opt",
            summary='Help msg string'),
        "int_opt": IntCfg(
            short_param='-i',
            long_param="--int-opt",
            summary='Help msg int'),
        "float_opt": FloatCfg(
            short_param='-f',
            long_param="--float-opt",
            summary='Help msg float'),
        "bool_opt": BoolCfg(
            short_param='-b',
            long_param="--bool-opt",
            summary='Help msg bool'),
})

Setting values can be done by:

cfg.set_cfg_value("group1.float_opt", 2.0)