The configuration is provided by Config object which is a singleton. It means that you can access Config from any place of your code, without need of explicit initialisation.

import asab

# Initialize application object and hence the configuration
app = asab.Application()

# Access configuration values anywhere
my_conf_value = asab.Config['section_name']['key1']

Based on ConfigParser

The Config is inherited from Python Standard Library configparser.ConfigParser class. which implements a basic configuration language which provides a structure similar to what’s found in Microsoft Windows INI files.

class asab.config.ConfigParser[source]

Example of the configuration file:

User = hg

Port = 50022
ForwardX11 = no

And this is how you access configuration values:

>>> asab.Config['']['ForwardX11']

Multiline configuration entry

A multiline configuration entries are supported. An example:


Automatic load of configuration

If a configuration file name is specified, the configuration is automatically loaded from a configuration file during initialiation time of Application. The configuration file name can be specified by one of -c command-line argument (1), ASAB_CONFIG environment variable (2) or config [general] config_file default value (3).

./ -c ./etc/sample.conf

Including other configuration files

You can specify one or more additional configuration files that are loaded and merged from an main configuration file. It is done by [general] include configuration value. Multiple paths are separated by os.pathsep (: on Unix). The path can be specified as a glob (e.g. use of * and ? wildcard characters), it will be expanded by glob module from Python Standard Library. Included configuration files may not exists, this situation is silently ignored.


You can also use a multiline configuration entry:


Including ZooKeeper node in the configuration

The separator between includes is newline or space - it means that space MUST NOT be in the names of nodes in the ZooKeeper.

The ZooKeeper node can contain a configuration file in .conf, .json or .yaml format.

You can specify servers and path of the ZooKeeper node directly in the include option:


It is also possible to name only the node path in this section and use zookeeper` configuration section to read the location of ZooKeeper servers. Using the environment variable ASAB_ZOOKEEPERS_SERVERS is also a possible option.


Configuration default values


This is how you can extend configuration default values:

        'section_name': {
            'key1': 'value',
            'key2': 'another value'
        'other_section': {
            'key3': 'value',

Only simple types (string, int and float) are allowed in the configuration values. Don’t use complex types such as lists, dictionaries or objects because these are impossible to provide via configuration files etc.

Environment variables in configration

Environment variables found in values are automatically expanded.

>>> asab.Config['section_name']['persistent_dir']

There is a special environment variable ${THIS_DIR} that is expanded to a directory that contains a current configuration file. It is useful in complex configurations that utilizes included configuration files etc.


Another environment variable ${HOSTNAME} contains the application hostname to be used f. e. in logging file path.


Passwords in configration

[passwords] section in the configuration serves to securely store passwords, which are then not shown publicly in the default API config endpoint’s output.

It is convenient for the user to store passwords at one place, so that they are not repeated in many sections of the config file(s).

Usage is as follows:



Obtaining seconds


The seconds can be obtained using getseconds() method for values with different time units specified in the configuration:


The available units are:

  • y … years
  • M … months
  • w … weeks
  • d … days
  • h … hours
  • m … minutes
  • s … seconds
  • ms .. miliseconds

If no unit is specified, float of seconds is expected.

The obtainment of the second value in the code can be achieved in two ways:

self.SleepTime = asab.Config["sleep"].getseconds("sleep_time")
self.AnotherSleepTime = asab.Config.getseconds("sleep", "another_sleep_time")

Obtaining URLs

Config.geturl(section, option, scheme=None:str, tuple)

A URL can be obtained using a geturl() method that takes the URL from the config and removes leading and trailing whitespaces and trailing backslashes.

There is an optional parameter called scheme that can have any URL scheme like http, https, mongodb etc. Setting it to None, scheme validation gets bypassed.

Setting the scheme parameter to the same scheme as in the config, it will return the URL. If it’s not the same it will raise an error.

There are two ways of obtaining the URL:

asab.Config["urls"].geturl("teskalabs", scheme="https")
asab.Config.geturl("urls", "github", scheme=None)


>>> asab.Config["urls"].geturl("teskalabs", scheme="https")

For reference this would be the configuration file: