docker-compose/compose/cli/utils.py

from __future__ import absolute_import
from __future__ import division
from __future__ import unicode_literals

import os
import platform
import ssl
import subprocess

import six
from docker import version as docker_py_version
from six.moves import input

from .. import __version__


def yesno(prompt, default=None):
    """
    Prompt the user for a yes or no.

    Can optionally specify a default value, which will only be
    used if they enter a blank line.

    Unrecognised input (anything other than "y", "n", "yes",
    "no" or "") will return None.
    """
    answer = input(prompt).strip().lower()

    if answer == "y" or answer == "yes":
        return True
    elif answer == "n" or answer == "no":
        return False
    elif answer == "":
        return default
    else:
        return None


def split_buffer(reader, separator):
    """
    Given a generator which yields strings and a separator string,
    joins all input, splits on the separator and yields each chunk.

    Unlike string.split(), each chunk includes the trailing
    separator, except for the last one if none was found on the end
    of the input.
    """
    buffered = six.text_type('')
    separator = six.text_type(separator)

    for data in reader:
        buffered += data.decode('utf-8')
        while True:
            index = buffered.find(separator)
            if index == -1:
                break
            yield buffered[:index + 1]
            buffered = buffered[index + 1:]

    if len(buffered) > 0:
        yield buffered


def call_silently(*args, **kwargs):
    """
    Like subprocess.call(), but redirects stdout and stderr to /dev/null.
    """
    with open(os.devnull, 'w') as shutup:
        return subprocess.call(*args, stdout=shutup, stderr=shutup, **kwargs)


def is_mac():
    return platform.system() == 'Darwin'


def is_ubuntu():
    return platform.system() == 'Linux' and platform.linux_distribution()[0] == 'Ubuntu'


def get_version_info(scope):
    versioninfo = 'docker-compose version: %s' % __version__
    if scope == 'compose':
        return versioninfo
    elif scope == 'full':
        return versioninfo + '\n' \
            + "docker-py version: %s\n" % docker_py_version \
            + "%s version: %s\n" % (platform.python_implementation(), platform.python_version()) \
            + "OpenSSL version: %s" % ssl.OPENSSL_VERSION
    else:
        raise RuntimeError('passed unallowed value to `cli.utils.get_version_info`')