Configuring XOS

The xosconfig module is used to read, validate and distribute configuration information for all XOS-related components.

The code for this module can be found in lib/xos-config

The xosconfig module uses a combination of parameters provided via a .yaml file and a service discovery mechanism.

How to Use This Module

This module needs to be initialized once (and only once) when you start the application. You can do it with:

from xosconfig import Config
Config.init()

By default, xosconfig looks for a configuration file in /opt/xos/config.yaml. Passing a different config file can be done with:

from xosconfig import Config
Config.init("/path/to/my/config.yaml")

Defaults are defined for some of the configuration items in lib/xos-config/xosconfig/default.py.

To access static information defined in the config.yaml file, use the following API:

from xosconfig import Config
res = Config.get('database')

This call returns something like:

{
    'username': 'test',
    'password': 'safe'
}

Since the configuration supports a nested dictionary, it is possible to query directly nested values using dot notation. For example:

from xosconfig import Config
res = Config.get('database.username')

returns

"test"

The configuration schema is defined in /lib/xos-config/config-schema.yaml

XOS is composed of a set of services. To discover these services and their address, use the registrator tool.

Invoking

from xosconfig import Config
Config.get_service_list()

returns an array of available services; by default:

[
  "xos-ws",
  "xos-ui-deprecated",
  "xos-rest",
  "xos-gui",
  "xos-db",
  "consul-rest",
  "consul",
]

You can get the same information on the head node using:
curl consul:8500/v1/catalog/services

Invoking

from xosconfig import Config
Config.get_service_info('xos-db')

returns

{
    'name': 'xos-db',
    'url': '172.18.0.4',
    'port': 5432
}

You can get the same information on the head node using:
curl consul:8500/v1/catalog/service/xos-db

Invoking

from xosconfig import Config
Config.get_service_endpoint('xos-db')

returns

"http://172.18.0.4:5432"