Advanced configuration#

This tutorial teaches you how to

  • Definine your own config options

  • Definine default configuration across multiple experiments

Define your own config options#

Defining your own config options is as easy as adding them to your config.conf. Let’s illustrate this with an example. Here, we first define a new section “custom” in config.conf, and add an option of name “my_option”, which we equip with a value:

# config.conf
[custom]
my_option = Value defined in config.conf

Now, in our script.py we can access the values defined in config.conf (and the default values provided by alfred) anywhere where we have access to the ExperimentSession object. That’s usually the case in hooks. Here, we just display the value defined in config.conf:

# script.py
import alfred3 as al
exp = al.Experiment()

@exp.member
class Demo(al.Page):

    def on_exp_access(self):

        text = self.exp.config.get("custom", "my_option")
        self += al.Text(text)

Note

Notes

  • Keep in mind that script.py and config.conf need to reside in the same directory (the experiment directory).

  • The behavior documented here works exactly the same for secrets.conf

  • Since we use a configparser.ConfigParser as the base for alfred’s config handling, you need to know that you have to explicitly define the type of object that you want to retrieve when accessing a config option. ConfigParser provides four distinct methods for this purpose:

ConfigParser.get()

returns a string

ConfigParser.getint()

returns an integer

ConfigParser.getfloat()

returns a floating point number

ConfigParser.getboolean()

returns a boolean value

Warning

It is recommended, that you place your custom options only a new section dedicated entirely for custom options, like in the example above. Otherwise you are at a risk of unknowingly overriding default options defined by alfred.

See Also:

  • Documentation on hooks: How to use hooks

  • API documentation of alfred’s config classes: alfred3.config

Define default configuration#

User-defined configuration files that can affect multiple experiments are parsed in the following order (later files override settings from earlier ones):

  1. “alfred.conf” (“secrets.conf” for secrets) in “/etc/alfred/” (for unix operating systems)

  2. “alfred.conf” (“secrets.conf”) in the user’s home directory

  3. File found under path given in the environment variable “ALFRED_CONFIG_FILE” (“ALFRED_SECRETS_FILE”)

Note

A config.conf (secrets.conf) in the experiment directory will always be parsed last and override any default configuration.