community.general/lib/ansible/module_utils/connection.py

#
# This code is part of Ansible, but is an independent component.
# This particular file snippet, and this file snippet only, is BSD licensed.
# Modules you write using this snippet, which is embedded dynamically by Ansible
# still belong to the author of the module, and may assign their own license
# to the complete work.
#
# (c) 2017 Red Hat Inc.
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# are permitted provided that the following conditions are met:
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#    * Redistributions of source code must retain the above copyright
#      notice, this list of conditions and the following disclaimer.
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#      and/or other materials provided with the distribution.
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# USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

import os
import hashlib
import json
import socket
import struct
import traceback
import uuid

from functools import partial
from ansible.module_utils._text import to_bytes, to_text
from ansible.module_utils.six import iteritems
from ansible.module_utils.six.moves import cPickle


def write_to_file_descriptor(fd, obj):
    """Handles making sure all data is properly written to file descriptor fd.

    In particular, that data is encoded in a character stream-friendly way and
    that all data gets written before returning.
    """
    # Need to force a protocol that is compatible with both py2 and py3.
    # That would be protocol=2 or less.
    # Also need to force a protocol that excludes certain control chars as
    # stdin in this case is a pty and control chars will cause problems.
    # that means only protocol=0 will work.
    src = cPickle.dumps(obj, protocol=0)

    # raw \r characters will not survive pty round-trip
    # They should be rehydrated on the receiving end
    src = src.replace(b'\r', br'\r')
    data_hash = to_bytes(hashlib.sha1(src).hexdigest())

    os.write(fd, b'%d\n' % len(src))
    os.write(fd, src)
    os.write(fd, b'%s\n' % data_hash)


def send_data(s, data):
    packed_len = struct.pack('!Q', len(data))
    return s.sendall(packed_len + data)


def recv_data(s):
    header_len = 8  # size of a packed unsigned long long
    data = to_bytes("")
    while len(data) < header_len:
        d = s.recv(header_len - len(data))
        if not d:
            return None
        data += d
    data_len = struct.unpack('!Q', data[:header_len])[0]
    data = data[header_len:]
    while len(data) < data_len:
        d = s.recv(data_len - len(data))
        if not d:
            return None
        data += d
    return data


def exec_command(module, command):
    connection = Connection(module._socket_path)
    try:
        out = connection.exec_command(command)
    except ConnectionError as exc:
        code = getattr(exc, 'code', 1)
        message = getattr(exc, 'err', exc)
        return code, '', to_text(message, errors='surrogate_then_replace')
    return 0, out, ''


def request_builder(method_, *args, **kwargs):
    reqid = str(uuid.uuid4())
    req = {'jsonrpc': '2.0', 'method': method_, 'id': reqid}
    req['params'] = (args, kwargs)

    return req


class ConnectionError(Exception):

    def __init__(self, message, *args, **kwargs):
        super(ConnectionError, self).__init__(message)
        for k, v in iteritems(kwargs):
            setattr(self, k, v)


class Connection(object):

    def __init__(self, socket_path):
        if socket_path is None:
            raise AssertionError('socket_path must be a value')
        self.socket_path = socket_path

    def __getattr__(self, name):
        try:
            return self.__dict__[name]
        except KeyError:
            if name.startswith('_'):
                raise AttributeError("'%s' object has no attribute '%s'" % (self.__class__.__name__, name))
            return partial(self.__rpc__, name)

    def _exec_jsonrpc(self, name, *args, **kwargs):

        req = request_builder(name, *args, **kwargs)
        reqid = req['id']

        if not os.path.exists(self.socket_path):
            raise ConnectionError('socket_path does not exist or cannot be found.'
                                  '\nSee the socket_path issue catergory in Network Debug and Troubleshooting Guide')

        try:
            data = json.dumps(req)
        except TypeError as exc:
            data = req.get('params')

            if isinstance(data, dict):
                data = data.get('var_options', {})

                for key, value in iteritems(data):
                    try:
                        dummy = json.dumps(value)
                    except TypeError:
                        raise ConnectionError(
                            "Failed to encode some variables as JSON for communication with ansible-connection. "
                            "Please open an issue and mention that the culprit is most likely '%s'" % key
                        )

            raise ConnectionError(
                "Failed to encode some variables as JSON for communication with ansible-connection. "
                "The original exception was: %s" % to_text(exc)
            )

        try:
            out = self.send(data)
        except socket.error as e:
            raise ConnectionError('unable to connect to socket. See the socket_path issue catergory in Network Debug and Troubleshooting Guide',
                                  err=to_text(e, errors='surrogate_then_replace'), exception=traceback.format_exc())

        try:
            response = json.loads(out)
        except ValueError:
            params = list(args) + ['{0}={1}'.format(k, v) for k, v in iteritems(kwargs)]
            params = ', '.join(params)
            raise ConnectionError(
                "Unable to decode JSON from response to {0}({1}). Received '{2}'.".format(name, params, out)
            )

        if response['id'] != reqid:
            raise ConnectionError('invalid json-rpc id received')

        return response

    def __rpc__(self, name, *args, **kwargs):
        """Executes the json-rpc and returns the output received
           from remote device.
           :name: rpc method to be executed over connection plugin that implements jsonrpc 2.0
           :args: Ordered list of params passed as arguments to rpc method
           :kwargs: Dict of valid key, value pairs passed as arguments to rpc method

           For usage refer the respective connection plugin docs.
        """

        response = self._exec_jsonrpc(name, *args, **kwargs)

        if 'error' in response:
            err = response.get('error')
            msg = err.get('data') or err['message']
            code = err['code']
            raise ConnectionError(to_text(msg, errors='surrogate_then_replace'), code=code)

        return response['result']

    def send(self, data):
        try:
            sf = socket.socket(socket.AF_UNIX, socket.SOCK_STREAM)
            sf.connect(self.socket_path)

            send_data(sf, to_bytes(data))
            response = recv_data(sf)

        except socket.error as e:
            sf.close()
            raise ConnectionError('unable to connect to socket', err=to_text(e, errors='surrogate_then_replace'), exception=traceback.format_exc())

        sf.close()

        return to_text(response, errors='surrogate_or_strict')