In addition to this, you can set the configuration option to be mandatory by setting the optional key to false. This will block the charm and stop services until the configuration is supplied. For example, if your application needs an api-token to function correctly you can set optional, as shown below. This will block the charm and stop the services until the api-token configuration is supplied.

charmcraft.yaml

config:
  options:
    api-token:
      description: The token necessary for the service to run.
      type: string
      optional: false

Note

A configuration with optional: false can’t also have a default key. If it has both, the charm will fail to pack.