# Internal API Reference

This document serves as a reference for the python API used in stestr. It should serve as a guide for both internal and external use of stestr components via python. The majority of the contents here are built from internal docstrings in the actual code.

## Repository

- Abstract Repository Class
- File Repository Type
- Memory Repository Type
- SQL Repository Type

## Commands

These modules are used for the operation of all the various subcommands in stestr. As of the 1.0.0 release each of these commands should be considered a stable interface that can be relied on externally.

Each command module conforms to a basic format that is used by `stestr.cli` to load each command. The basic structure for these modules is the following three functions:

    def get_cli_help():
        """This function returns a string that is used for the subcommand help"""
        help_str = "A descriptive help string about the command"
        return help_str

    def get_cli_opts(parser):
        """This function takes a parser and any subcommand arguments are defined
           here"""
        parser.add_argument(...)

    def run(arguments):
        """This function actually runs the command. It takes in a tuple arguments
           which the first element is the argparse Namespace object with the
           arguments from the parser. The second element is a list of unknown
           arguments from the CLI. The expectation of the run method is that it
           will process the arguments and call another function that does the
           real work. The return value is expected to be an int and is used for
           the exit code (assuming the function doesn't call sys.exit() on it's
           own)"""
        args = arguments[0]
        unknown_args = arguments[1]
        return call_foo()

The command module will not work if all 3 of these function are not defined. However, to make the commands externally consumable each module also contains another public function which performs the real work for the command. Each one of these functions has a defined stable Python API signature with args and kwargs so that people can easily call the functions from other python programs. This function is what can be expected to be used outside of stestr as the stable interface. All the stable functions can be imported the the command module directly:

    from stestr import command

    def my_list():
        command.list_command(...)

- stestr Commands
- stestr failing Command
- stestr init Command
- stestr last Command
- stestr list Command
- stestr load Command
- stestr run Command
- stestr slowest Command

## Internal APIs

The modules in this list do not necessarily have any external api contract, they are intended for internal use inside of stestr. If anything in these provides a stable contract and is intended for usage outside of stestr it will be noted in the api doc.

- Configuration File Module
- Test Selection Module
- The Scheduler Module
- The Output Module
- Test Processor Module
  - API Reference
- Subunit Trace