12. pypsi.wizard - Prompt Wizards

Command line input wizards.

class pypsi.wizard.PromptWizard(name, description, steps=None, features=None)[source]

Bases: object

A user input prompt wizards.

PromptWizards will walk the user through a series of questions (WizardStep) and accept input. The user may at any time enter the ? key to get help regarding the current step.

Each step can have validators that determine if a value is valid before proceeding to the next step. Also, each step can have a default value that is saved if the user hits Return with no input.

Once complete, the wizard will return a Namespace object that contains all the user’s answers. Each step contains an id attribute that determines what variable is set in the returned namespace.

For example, a step may have an id of "ip_addr". When the user enters "192.168.0.1" for this step, the input can be retrieved through the namespace’s ip_addr attribute.

Parameters:
  • name (str) – the prompt wizard name to display to the user
  • description (str) – a short description of what the wizard does
  • steps (list) – a list of WizardStep objects
complete(text, state)[source]

Tab complete for the current step.

run(shell, print_header=True)[source]

Execute the wizard, prompting the user for input.

Parameters:shell (pypsi.shell.Shell) – the active shell
Returns:a Namespace object containing all the answers on success, None if the user exited the wizard
class pypsi.wizard.WizardStep(id, name, help, default=None, completer=None, validators=None)[source]

Bases: object

A single input step in a prompt wizard.

Parameters:
  • id (str) – the step io, used for referencing the step’s value
  • name (str) – the name to display for input to the user
  • help (str) – the help message to display to the user
  • default (str) – the default value if the user immediately hits “Return”
  • completer – a completion function
  • validators – a single or a list of validators
complete(wizard, args, prefix)[source]

Get the list of possible completions for input. This will call the local completer function (self.completer with the arguments: (wizard, args, prefix).

  • wizard (PromptWizard) - the active wizard
  • args (list) - the list of input arguments
  • prefix (str) - the input prefix

This function mirrors the command complete() function.

validate(ns, value)[source]

Validate the input value. This will call the local validators (self.validators) sequentially with the following arguments:

  • ns (Namespace) - the current input values
  • value - the value to validate

Validators may change the value in place (if it is a mutable object) or may return the validated value that will be passed to the remaining validators. If a validation error occurs, raise a ValueError exception.

Parameters:
Returns:

validated value
pypsi.wizard.boolean_validator(ns, value)[source]

Boolean validator. Raises ValueError if input isn’t a boolean string.

Parameters:
Returns bool:

validated value
pypsi.wizard.choice_validator(choices)[source]

String choice validator. Raises ValueError if input isn’t a valid choice.

Parameters:choices (list) – valid choices
Returns:validator function
pypsi.wizard.directory_validator(ns, value)[source]

Directory path validator. Raises ValueError on validation error.

Parameters:
Returns:

validated value
pypsi.wizard.file_validator(ns, value)[source]

File path validator. Raises ValueError on validation error.

Parameters:
Returns:

validated value
pypsi.wizard.hostname_or_ip_validator(ns, value)[source]

Network hostname or IPv4 address validator. Raises ValueError on validation error.

Parameters:
Returns:

validated value
pypsi.wizard.int_validator(min=None, max=None)[source]

Integer value wizard validator creator.

Parameters:
  • min (int) – minimum value, None if no minimum
  • max (int) – maximum value, None if no maximum
Returns:

validator function
pypsi.wizard.lowercase_validator(ns, value)[source]

Converts input string to lowercase.

Parameters:
Returns:

validated value (in lowercase)
pypsi.wizard.module_name_validator(type_str)[source]

Python module name validator. Raises ValueError on validation error.

Parameters:type_str (str) – the input type to reference when raising validation errors.
Returns:validator function
pypsi.wizard.package_name_validator(type_str)[source]

Python package name validator. Raises ValueError on validation error.

Parameters:type_str (str) – the input type to reference when raising validation errors.
Returns:validator function
pypsi.wizard.required_validator(ns, value)[source]

Required value wizard validator. Raises ValueError on validation error.

Parameters:
Returns:

validated value