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validators

env_var(arg_value)

Read a value from the environment.

Parameters:

Name Type Description Default
arg_value str

The input provided by argparse.

 required

Returns:

Type Description
str

The environment variable value if it exists. Otherwise, the input.
Source code in m/cli/validators.py 
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def env_var(arg_value: str) -> str:
    """Read a value from the environment.

    Args:
        arg_value: The input provided by argparse.

    Returns:
        The environment variable value if it exists. Otherwise, the input.
    """
    return os.environ.get(arg_value, arg_value)

env_var_or_empty(arg_value)

Read a value from the environment.

Unlike the env_var validator, this will only allow the arg_value to pass through if is not in the form of an environment variable. That is, if the value is all uppercase letters and underscores it will attempt to read from the environment and return an empty string if not defined.

Parameters:

Name Type Description Default
arg_value str

The input provided by argparse.

 required

Returns:

Type Description
str

The environment variable value if it exists. Otherwise, empty string.
Source code in m/cli/validators.py 
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def env_var_or_empty(arg_value: str) -> str:
    """Read a value from the environment.

    Unlike the [env_var][m.cli.validators.env_var] validator, this will only
    allow the `arg_value` to pass through if is not in the form of an
    environment variable. That is, if the value is all uppercase letters and
    underscores it will attempt to read from the environment and return an empty
    string if not defined.

    Args:
        arg_value: The input provided by argparse.

    Returns:
        The environment variable value if it exists. Otherwise, empty string.
    """
    env_form = arg_value.upper().replace('-', '_', -1)
    if arg_value == env_form:
        return os.environ.get(arg_value, '')
    return arg_value

validate_file_exists(path)

Assert that a file exists.

Parameters:

Name Type Description Default
path str

The path to the file.

 required

Raises:

Type Description
ArgumentTypeError

If the file does not exist.

Returns:

Type Description
str

The path if it exists.
Source code in m/cli/validators.py 
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def validate_file_exists(path: str) -> str:
    """Assert that a file exists.

    Args:
        path: The path to the file.

    Raises:
        ArgumentTypeError: If the file does not exist.

    Returns:
        The path if it exists.
    """
    path_inst = Path(path)
    if path_inst.exists():
        return path
    raise ArgumentTypeError('file does not exist')

validate_json_payload(file_path)

Return a dictionary from the contents of file_path.

This is a string that tell us to read from a file, stdin or just plain json data.

It can be used parse yaml files as well. The extension should be .yaml or .yml.

Parameters:

Name Type Description Default
file_path str

A string with the json payload. If it starts with @ then the name of a valid json file from where the payload will be read.

 required

Raises:

Type Description
ArgumentTypeError

If the file_path is meant to be a valid path and it does not exist.

Returns:

Type Description
Any

A parsed json payload
Source code in m/cli/validators.py 
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def validate_json_payload(file_path: str) -> Any:
    """Return a dictionary from the contents of file_path.

    This is a string that tell us to read from a file, stdin or just
    plain json data.

    It can be used parse `yaml` files as well. The extension should be
    `.yaml` or `.yml`.

    Args:
        file_path: A string with the json payload. If it starts with `@` then
            the name of a valid json file from where the payload will be read.

    Raises:
        ArgumentTypeError: If the file_path is meant to be a valid path and it
            does not exist.

    Returns:
        A parsed json payload
    """
    if file_path == '@-':
        res = read_json(None)
        if res.is_bad:
            msg = f'invalid json payload in SYS.STDIN\n{res.value}'
            raise ArgumentTypeError(msg)
        return res.value
    if file_path.startswith('@'):
        err = ''
        filename = file_path[1:]
        if Path.exists(Path(filename)):
            res = read_yson(filename)
            if not res.is_bad:
                return res.value
            err = f'invalid json payload in {filename}\n{res.value}'
        else:
            err = f'file "{filename}" does not exist'
        if err:
            raise ArgumentTypeError(err)
    res = parse_json(file_path)
    if res.is_bad:
        raise ArgumentTypeError(f'invalid json payload\n{res.value}')
    return res.value

validate_non_empty_str(arg_value)

Return the value as long as its not empty.

Parameters:

Name Type Description Default
arg_value str

The input provided by argparse.

 required

Raises:

Type Description
ArgumentTypeError

If the input is not provided.

Returns:

Type Description
str

The value if non empty.
Source code in m/cli/validators.py 
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def validate_non_empty_str(arg_value: str) -> str:
    """Return the value as long as its not empty.

    Args:
        arg_value: The input provided by argparse.

    Raises:
        ArgumentTypeError: If the input is not provided.

    Returns:
        The value if non empty.
    """
    if not arg_value:
        raise ArgumentTypeError('empty value not allowed')
    return arg_value

validate_payload(file_path)

Return the raw payload.

This allows us to read from a file or the stdin stream.

Parameters:

Name Type Description Default
file_path str

A string with the payload. If it starts with @ then the name of a valid file from where the payload will be read.

 required

Raises:

Type Description
ArgumentTypeError

If the file_path is meant to be a valid path and it does not exist.

Returns:

Type Description
str

The payload found in the file.
Source code in m/cli/validators.py 
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def validate_payload(file_path: str) -> str:
    """Return the raw payload.

    This allows us to read from a file or the stdin stream.

    Args:
        file_path: A string with the payload. If it starts with `@` then the
            name of a valid file from where the payload will be read.

    Raises:
        ArgumentTypeError: If the file_path is meant to be a valid path and it
            does not exist.

    Returns:
        The payload found in the file.
    """
    if file_path.startswith(r'\@'):
        # escape @ with \ to let the cli know that the payload starts with @
        return file_path[1:]
    if file_path == '@-':
        return sys.stdin.read()
    if file_path.startswith('@'):
        filename = file_path[1:]
        path_handle = Path(filename)
        if not Path.exists(path_handle):
            raise ArgumentTypeError(f'file "{filename}" does not exist')
        with Path.open(path_handle, encoding='UTF-8') as fp:
            return fp.read()
    return file_path