Config variables

note

This page reflects the options available in the most recent version of Batect.

Config variables allow you simplify your configuration file, and document and codify the different options available to someone using your tasks.

They are useful for a number of use cases:

• Reducing duplication in configuration files
• Simplifying management of developer-specific preferences (eg. a developer's preferred log output level)
• Simplifying management of sets of environment-specific settings (eg. managing sets of test environment connection settings for a CI server)

Config variables can be used anywhere expressions are supported. Reference config variables with the syntax <name or <{name}.

Values

Values for config variables are taken from the following sources, with earlier values taking precedence:

• a value provided on the command line with --config-var <name>=<value>
• a value specified in a config variables file, either the default batect.local.yml or specified with --config-vars-file
• the default value specified in its definition

If a variable is referenced but no value is available for it, an error occurs.

Built-in config variables

There is one built-in config variable:

batect.project_directory

Contains the full path to the directory containing the root configuration file in use.

Normally, this is the directory containing batect.yml, or the directory containing the configuration file if it has been with the --config-file or -f command line option.

This is particularly useful in configuration files imported into the project with includes. For example, if /my-project/a.yml contains:

/my-project/a.yml

include:
  - includes/b.yml

And /my-project/includes/b.yml contains:

/my-project/includes/b.yml

containers:
  my-container:
    image: alpine:1.2.3
    volumes:
      - local: <{batect.project_directory}/scripts
        container: /code/scripts

Then the directory /my-project/scripts will be mounted into the my-container container at /code/scripts.

Names

Config variable names must start with a letter and contain only letters, digits, dashes (-), periods (.) and underscores (_). They must not start with batect.

Definition

Each config variable definition is made up of:

description

A human-readable description of the variable.

default

The default value of the variable.

Examples

Config variable with no description or default value

config_variables:
  log_level: {}

{} is the YAML syntax for an empty object.

Config variable with description and default value

config_variables:
  log_level:
    description: Log level to use for application
    default: debug