Command line options

The logic which would parse the current command line and run something for it.

All codes belong to here section, they all are responsible for defining the command line and its options to let argpars understands how to parse the current command line.

UML

About the software architecture of this feature is already be introduced. Please refer to section Command line - UML.

Workflow

About the software workflow details of this feature is already be introduced. Please refer to section Command line - Workflow.

Extension

Here would demonstrate how to extend or add new sub-command feature.

You'll have 4 things:

Add new attribute of enum object SubCommandLine

Enum object SubCommandLine is the standard for PyFake-API-Server to recognize which sub-command it has. So let's add one new sub-command line here:

class SubCommandLine(Enum):

    # other enum ...

    NewProcess: str = "new-ps"

Implement new class about subcommand new-ps

Add new class extends base class BaseSubCommand and set value at attribute sub_parser.

class SubCommandNewProcessOption(BaseSubCommand):
    sub_cmd: SubCommandAttr = SubCommandAttr(
        title=SubCommandSection.Base,
        dest=SubCommandLine.Base,
        description="",
        help="",
    )
    sub_parser: SubParserAttr = SubParserAttr(
        name=SubCommand.NewProcess,
        help="New subcommand for demonstration,",
    )

Instantiate class with metaclass for subcommand new-ps

Instantiate a base class for adding options.

BaseSubCmdNewProcessOption: type = MetaCommandOption("BaseSubCmdNewProcessOption", (SubCommandNewProcessOption,), {})

It would auto-register this sub-command line into SUBCOMMAND. We have sub-command line new-ps, let's add its options.

Extend the subcommand object to add its option(s)

Add new command option with extending BaseSubCmdNewProcessOption and set needed attributes in it:

class Arg_1(BaseSubCmdNewProcessOption):

    cli_option: str = "--arg-1"
    name: str = "arg_1"
    help_description: str = "A parameter for demonstration of extending new subcommand and new option."

• cli_option: Define the option usage via command line.
• name: The attribute to get the option value from argpars.
• help_description: The description would be displayed if you run --help.

Finally, don't forget to let command line process know which sub-command line is its responsibility by overriding the class attribute responsible_subcommand:

# ... some code

class SubCmdNewProcess(BaseCommandProcessor):
    responsible_subcommand = SubCommand.NewProcess

    # ... some code

Now, let's try to run the PyFake-API-Server with new sub-command:

>>> fake new-ps --arg-1 test_value
This is new sub-command line and get option *arg_1*: test_value

Congratulation! It works finely as out expect.