Source code for gunittest.gmodules

"""
Specialized interfaces for invoking modules for testing framework

Copyright (C) 2014 by the GRASS Development Team
This program is free software under the GNU General Public
License (>=v2). Read the file COPYING that comes with GRASS GIS
for details.

:authors: Vaclav Petras, Soeren Gebbert
"""

import subprocess
from grass.script.core import start_command
from grass.script.utils import encode, decode
from grass.exceptions import CalledModuleError
from grass.pygrass.modules import Module

from .utils import do_doctest_gettext_workaround


class SimpleModule(Module):
    """Simple wrapper around pygrass.modules.Module to make sure that
    run\_, finish\_, stdout and stderr are set correctly.

    >>> mapcalc = SimpleModule('r.mapcalc', expression='test_a = 1',
    ...                        overwrite=True)
    >>> mapcalc.run()
    Module('r.mapcalc')
    >>> mapcalc.returncode
    0

    >>> colors = SimpleModule('r.colors',
    ...                       map='test_a', rules='-', stdin_='1 red')
    >>> colors.run()
    Module('r.colors')
    >>> colors.returncode
    0
    >>> str(colors.inputs.stdin)
    '1 red'
    >>> str(colors.outputs.stdout)
    ''
    >>> colors.outputs.stderr.strip()
    "Color table for raster map <test_a> set to 'rules'"
    """

    def __init__(self, cmd, *args, **kargs):
        for banned in ["stdout_", "stderr_", "finish_", "run_"]:
            if banned in kargs:
                raise ValueError(
                    "Do not set %s parameter" ", it would be overriden" % banned
                )
        kargs["stdout_"] = subprocess.PIPE
        kargs["stderr_"] = subprocess.PIPE
        kargs["finish_"] = True
        kargs["run_"] = False

        Module.__init__(self, cmd, *args, **kargs)


def call_module(
    module,
    stdin=None,
    merge_stderr=False,
    capture_stdout=True,
    capture_stderr=True,
    **kwargs,
):
    r"""Run module with parameters given in `kwargs` and return its output.

    >>> print (call_module('g.region', flags='pg'))  # doctest: +ELLIPSIS
    projection=...
    zone=...
    n=...
    s=...
    w=...
    >>> call_module('m.proj', flags='i', input='-', stdin="50.0 41.5")
    '8642890.65|6965155.61|0.00\n'
    >>> call_module('g.region', aabbbccc='notexist')  # doctest: +IGNORE_EXCEPTION_DETAIL
    Traceback (most recent call last):
        ...
    CalledModuleError: Module run g.region ... ended with error

    If `stdin` is not set and `kwargs` contains ``input`` with value set
    to ``-`` (dash), the function raises an error.

    Note that ``input`` nor ``output`` parameters are used by this
    function itself, these are usually module parameters which this
    function just passes to it. However, when ``input`` is in parameters
    the function checks if its values is correct considering value of
    ``stdin`` parameter.

    :param str module: module name
    :param stdin: string to be used as module standard input (stdin) or `None`
    :param merge_stderr: if the standard error output should be merged with stdout
    :param kwargs: module parameters

    :returns: module standard output (stdout) as string or None
              if capture_stdout is False

    :raises CalledModuleError: if module return code is non-zero
    :raises ValueError: if the parameters are not correct

    .. note::
        The data read is buffered in memory, so do not use this method
        if the data size is large or unlimited.
    """
    # TODO: remove this:
    do_doctest_gettext_workaround()
    # implementation inspired by subprocess.check_output() function
    if stdin:
        if "input" in kwargs and kwargs["input"] != "-":
            raise ValueError(_("input='-' must be used when stdin is specified"))
        if stdin == subprocess.PIPE:
            raise ValueError(_("stdin must be string or buffer, not PIPE"))
        kwargs["stdin"] = subprocess.PIPE  # to be able to send data to stdin
    elif "input" in kwargs and kwargs["input"] == "-":
        raise ValueError(_("stdin must be used when input='-'"))
    if merge_stderr and not (capture_stdout and capture_stderr):
        raise ValueError(_("You cannot merge stdout and stderr and not capture them"))
    if "stdout" in kwargs:
        raise TypeError(_("stdout argument not allowed, it could be overridden"))
    if "stderr" in kwargs:
        raise TypeError(_("stderr argument not allowed, it could be overridden"))

    if capture_stdout:
        kwargs["stdout"] = subprocess.PIPE
    if capture_stderr:
        if merge_stderr:
            kwargs["stderr"] = subprocess.STDOUT
        else:
            kwargs["stderr"] = subprocess.PIPE
    process = start_command(module, **kwargs)
    # input=None means no stdin (our default)
    # for no stdout, output is None which is out interface
    # for stderr=STDOUT or no stderr, errors is None
    # which is fine for CalledModuleError
    output, errors = process.communicate(input=encode(decode(stdin)) if stdin else None)
    returncode = process.poll()
    if returncode:
        raise CalledModuleError(module, kwargs, returncode, errors)
    return decode(output) if output else None