# Source code for pyeapi.eapilib

    #
    # Copyright (c) 2014, Arista Networks, Inc.
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    # Redistribution and use in source and binary forms, with or without
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    #   this list of conditions and the following disclaimer.
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    #   this software without specific prior written permission.
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    # THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
    # "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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    #
    """Provides wrapper for eAPI calls

    This module provides a connection to eAPI by wrapping eAPI calls in an
    instance of Connection.  The connection module provides an easy implementation
    for sending and receiving calls over eAPI using a HTTP/S transport.
    """

    import sys
    import json
    import socket
    import base64
    import logging
    import ssl
    import re

    try:
        # Try Python 3.x import first
        from http.client import HTTPConnection, HTTPSConnection
    except ImportError:
        # Use Python 2.7 import as a fallback
        from httplib import HTTPConnection, HTTPSConnection

    from pyeapi.utils import make_iterable

    _LOGGER = logging.getLogger(__name__)

    DEFAULT_HTTP_PORT = 80
    DEFAULT_HTTPS_PORT = 443
    DEFAULT_HTTP_LOCAL_PORT = 8080
    DEFAULT_HTTP_PATH = '/command-api'
    DEFAULT_UNIX_SOCKET = '/var/run/command-api.sock'

    def https_connection_factory(path, host, port, context=None, timeout=60):
        # ignore ssl context for python versions before 2.7.9
        if sys.hexversion < 34015728:
            return HttpsConnection(path, host, port, timeout=timeout)
        return HttpsConnection(path, host, port, context=context, timeout=timeout)

    class EapiError(Exception):
        """Base exception class for all exceptions generated by eapilib

        This is the base exception class for all exceptions generated by
        eapilib.  It is provided as a catch all for exceptions and should
        not be directly raised by an methods or functions

        Args:
            commands (array): The list of commands there were sent to the
                node that when the exception was raised
            message (string): The exception error message
        """
        def __init__(self, message, commands=None):
            self.message = message
            self.commands = commands
            super(EapiError, self).__init__(message)

    class CommandError(EapiError):
        """Base exception raised for command errors

        The CommandError instance provides a custom exception that can be used
        if the eAPI command(s) fail.  It provides some additional information
        that can be used to understand what caused the exception.

        Args:
            error_code (int): The error code returned from the eAPI call.
            error_text (string): The error text message that coincides with the
                error_code
            commands (array): The list of commands that were sent to the node
                that generated the error
            message (string): The exception error message which is a concatenation
                of the error_code and error_text
        """
        def __init__(self, code, message, **kwargs):
            cmd_err = kwargs.get('command_error')
            if int(code) in [1000, 1002, 1004]:
                msg_fmt = 'Error [{}]: {} [{}]'.format(code, message, cmd_err)
            else:
                msg_fmt = 'Error [{}]: {}'.format(code, message)

            super(CommandError, self).__init__(msg_fmt)
            self.error_code = code
            self.error_text = message
            self.command_error = cmd_err
            self.commands = kwargs.get('commands')
            self.output = kwargs.get('output')
            self.message = msg_fmt

        @property
        def trace(self):
            return self.get_trace()

        def get_trace(self):
            trace = list()
            index = None

            for index, out in enumerate(self.output):
                _entry = {'command': self.commands[index], 'output': out}
                trace.append(_entry)

            if index:
                index += 1
                for cmd in self.commands[index:]:
                    _entry = {'command': cmd, 'output': None}
                    trace.append(_entry)

            return trace

    class ConnectionError(EapiError):
        """Base exception raised for connection errors

        Connection errors are raised when a connection object is unable to
        connect to the node.  Typically these errors can result from using
        the wrong transport type or not providing valid credentials.

        Args:
            commands (array): The list of commands there were sent to the
                node that when the exception was raised
            connection_type (string): The string identifier for the connection
                object that generate the error
            message (string): The exception error message
            response (string): The message generate from the response packet

        """
        def __init__(self, connection_type, message, commands=None):
            self.message = message
            self.connection_type = connection_type
            self.commands = commands
            super(ConnectionError, self).__init__(message)

    class SocketConnection(HTTPConnection):

        def __init__(self, path, timeout=60):
            HTTPConnection.__init__(self, 'localhost')
            self.path = path
            self.timeout = timeout

        def __str__(self):
            return 'unix:%s' % self.path

        def __repr__(self):
            return 'unix:%s' % self.path

        def connect(self):
            self.sock = socket.socket(socket.AF_UNIX, socket.SOCK_STREAM)
            self.sock.settimeout(self.timeout)
            self.sock.connect(self.path)

    class HttpConnection(HTTPConnection):

        def __init__(self, path, *args, **kwargs):
            HTTPConnection.__init__(self, *args, **kwargs)
            self.path = path

        def __str__(self):
            return 'http://%s:%s/%s' % (self.host, self.port, self.path)

        def __repr__(self):
            return 'http://%s:%s/%s' % (self.host, self.port, self.path)

    class HttpsConnection(HTTPSConnection):

        def __init__(self, path, *args, **kwargs):
            HTTPSConnection.__init__(self, *args, **kwargs)
            self.path = path

        def __str__(self):
            return 'https://%s:%s/%s' % (self.host, self.port, self.path)

        def __repr__(self):
            return 'https://%s:%s/%s' % (self.host, self.port, self.path)

    class EapiConnection(object):
        """Creates a connection to eAPI for sending and receiving eAPI requests

        The EapiConnection object provides an implementation for sending and
        receiving eAPI requests and responses.  This class should not need to
        be instantiated directly.
        """

        def __init__(self):
            self.transport = None
            self.error = None
            self.socket_error = None
            self._auth = None

        def __str__(self):
            return 'EapiConnection(transport=%s)' % str(self.transport)

        def __repr__(self):
            return 'EapiConnection(transport=%s)' % repr(self.transport)

        def authentication(self, username, password):
            """Configures the user authentication for eAPI

            This method configures the username and password combination to use
            for authenticating to eAPI.

            Args:
                username (str): The username to use to authenticate the eAPI
                    connection with
                password (str): The password in clear text to use to authenticate
                    the eAPI connection with

            """
            # Work around for Python 2.7/3.x compatibility
            if int(sys.version[0]) > 2:
                # For Python 3.x
                _auth_text = '{}:{}'.format(username, password)
                _auth_bin = base64.encodebytes(_auth_text.encode())
                _auth = _auth_bin.decode()
                _auth = _auth.replace('\n', '')
                self._auth = _auth
            else:
                # For Python 2.7
                _auth = base64.encodestring('{}:{}'.format(username, password))
                self._auth = str(_auth).replace('\n', '')

            _LOGGER.debug('Autentication string is: {}'.format(self._auth))

        def request(self, commands, encoding=None, reqid=None, **kwargs):
            """Generates an eAPI request object

            This method will take a list of EOS commands and generate a valid
            eAPI request object form them.  The eAPI request object is then
            JSON encoding and returned to the caller.

            eAPI Request Object

            .. code-block:: json

                {
                    "jsonrpc": "2.0",
                    "method": "runCmds",
                    "params": {
                        "version": 1,
                        "cmds": [
                            <commands>
                        ],
                        "format": [json, text],
                    }
                    "id": <reqid>
                }

            Args:
                commands (list): A list of commands to include in the eAPI
                    request object
                encoding (string): The encoding method passed as the `format`
                    parameter in the eAPI request
                reqid (string): A custom value to assign to the request ID
                    field.  This value is automatically generated if not passed
                **kwargs: Additional keyword arguments for expanded eAPI
                    functionality. Only supported eAPI params are used in building
                    the request

            Returns:
                A JSON encoding request structure that can be send over eAPI

            """
            commands = make_iterable(commands)
            reqid = id(self) if reqid is None else reqid
            params = {'version': 1, 'cmds': commands, 'format': encoding}
            if 'autoComplete' in kwargs:
                params['autoComplete'] = kwargs['autoComplete']
            if 'expandAliases' in kwargs:
                params['expandAliases'] = kwargs['expandAliases']
            return json.dumps({'jsonrpc': '2.0', 'method': 'runCmds',
                               'params': params, 'id': str(reqid)})

        def send(self, data):
            """Sends the eAPI request to the destination node

            This method is responsible for sending an eAPI request to the
            destination node and returning a response based on the eAPI response
            object.  eAPI responds to request messages with either a success
            message or failure message.

            eAPI Response - success

            .. code-block:: json

                {
                    "jsonrpc": "2.0",
                    "result": [
                        {},
                        {}
                        {
                            "warnings": [
                                <message>
                            ]
                        },
                    ],
                    "id": <reqid>
                }

            eAPI Response - failure

            .. code-block:: json

                {
                    "jsonrpc": "2.0",
                    "error": {
                        "code": <int>,
                        "message": <string>
                        "data": [
                            {},
                            {},
                            {
                                "errors": [
                                    <message>
                                ]
                            }
                        ]
                    }
                    "id": <reqid>
                }

            Args:
                data (string): The data to be included in the body of the eAPI
                    request object

            Returns:
                A decoded response.  The response object is deserialized from
                    JSON and returned as a standard Python dictionary object

            Raises:
                CommandError if an eAPI failure response object is returned from
                    the node.   The CommandError exception includes the error
                    code and error message from the eAPI response.
            """
            try:
                _LOGGER.debug('Request content: {}'.format(data))
                # debug('eapi_request: %s' % data)

                self.transport.putrequest('POST', '/command-api')

                self.transport.putheader('Content-type', 'application/json-rpc')
                self.transport.putheader('Content-length', '%d' % len(data))

                if self._auth:
                    self.transport.putheader('Authorization',
                                             'Basic %s' % self._auth)

                if int(sys.version[0]) > 2:
                    # For Python 3.x compatibility
                    data = data.encode()

                self.transport.endheaders(message_body=data)

                try:  # Python 2.7: use buffering of HTTP responses
                    response = self.transport.getresponse(buffering=True)
                except TypeError:  # Python 2.6: older, and 3.x on
                    response = self.transport.getresponse()

                response_content = response.read()
                _LOGGER.debug('Response: status:{status}, reason:{reason}'.format(
                              status=response.status,
                              reason=response.reason))
                _LOGGER.debug('Response content: {}'.format(response_content))

                # Work around for Python 2.7/3.x compatibility
                if not type(response_content) == str:
                    # For Python 3.x - decode bytes into string
                    response_content = response_content.decode()
                decoded = json.loads(response_content)
                _LOGGER.debug('eapi_response: %s' % decoded)

                if 'error' in decoded:
                    (code, msg, err, out) = self._parse_error_message(decoded)
                    pattern = "unexpected keyword argument '(.*)'"
                    match = re.search(pattern, msg)
                    if match:
                        auto_msg = ('%s parameter is not supported in this'
                                    ' version of EOS.' % match.group(1))
                        _LOGGER.error(auto_msg)
                        msg = msg + '. ' + auto_msg
                    raise CommandError(code, msg, command_error=err, output=out)

                return decoded

            # socket.error is deprecated in python 3 and replaced with OSError.
            except (socket.error, OSError, ValueError) as exc:
                if isinstance(exc, socket.error) or isinstance(exc, OSError):
                    self.socket_error = exc
                _LOGGER.exception(exc)
                self.error = exc
                error_msg = 'unable to connect to eAPI'
                if self.socket_error:
                    error_msg = ('Socket error during eAPI connection: %s'
                                 % str(exc))
                raise ConnectionError(str(self), error_msg)

            finally:
                self.transport.close()

        def _parse_error_message(self, message):
            """Parses the eAPI failure response message

            This method accepts an eAPI failure message and parses the necesary
            parts in order to generate a CommandError.

            Args:
                message (str): The error message to parse

            Returns:
                tuple: A tuple that consists of the following:
                    * code: The error code specified in the failure message
                    * message: The error text specified in the failure message
                    * error: The error text from the command that generated the
                        error (the last command that ran)
                    * output: A list of all output from all commands
            """
            msg = message['error']['message']
            code = message['error']['code']

            err = None
            out = None

            if 'data' in message['error']:
                err = ' '.join(message['error']['data'][-1]['errors'])
                out = message['error']['data']

            return code, msg, err, out

        def execute(self, commands, encoding='json', **kwargs):
            """Executes the list of commands on the destination node

            This method takes a list of commands and sends them to the
            destination node, returning the results.  The execute method handles
            putting the destination node in enable mode and will pass the
            enable password, if required.

            Args:
                commands (list): A list of commands to execute on the remote node
                encoding (string): The encoding to send along with the request
                    message to the destination node.  Valid values include 'json'
                    or 'text'.  This argument will influence the response object
                    encoding
                **kwargs: Arbitrary keyword arguments

            Returns:
                A decoded response message as a native Python dictionary object
                that has been deserialized from JSON.

            Raises:
                CommandError:  A CommandError is raised that includes the error
                    code, error message along with the list of commands that were
                    sent to the node.  The exception instance is also stored in
                    the error property and is availble until the next request is
                    sent
            """
            if encoding not in ('json', 'text'):
                raise TypeError('encoding must be one of [json, text]')

            try:
                self.error = None
                request = self.request(commands, encoding=encoding, **kwargs)
                response = self.send(request)
                return response

            except(ConnectionError, CommandError, TypeError) as exc:
                exc.commands = commands
                self.error = exc
                raise

    class SocketEapiConnection(EapiConnection):
        def __init__(self, path=None, timeout=60, **kwargs):
            super(SocketEapiConnection, self).__init__()
            path = path or DEFAULT_UNIX_SOCKET
            self.transport = SocketConnection(path, timeout)

    class HttpLocalEapiConnection(EapiConnection):
        def __init__(self, port=None, path=None, timeout=60, **kwargs):
            super(HttpLocalEapiConnection, self).__init__()
            port = port or DEFAULT_HTTP_LOCAL_PORT
            path = path or DEFAULT_HTTP_PATH
            self.transport = HttpConnection(path, 'localhost', int(port),
                                            timeout=timeout)

    class HttpEapiConnection(EapiConnection):
        def __init__(self, host, port=None, path=None, username=None,
                     password=None, timeout=60, **kwargs):
            super(HttpEapiConnection, self).__init__()
            port = port or DEFAULT_HTTP_PORT
            path = path or DEFAULT_HTTP_PATH
            self.transport = HttpConnection(path, host, int(port), timeout=timeout)
            self.authentication(username, password)

    class HttpsEapiConnection(EapiConnection):
        def __init__(self, host, port=None, path=None, username=None,
                     password=None, context=None, timeout=60, **kwargs):
            super(HttpsEapiConnection, self).__init__()
            port = port or DEFAULT_HTTPS_PORT
            path = path or DEFAULT_HTTP_PATH

            enforce_verification = kwargs.get('enforce_verification')

            if context is None and not enforce_verification:
                context = self.disable_certificate_verification()

            self.transport = https_connection_factory(path, host, int(port),
                                                      context, timeout)
            self.authentication(username, password)

        def disable_certificate_verification(self):
            # SSL/TLS certificate verification is enabled by default in latest
            # Python releases and causes self-signed certificates generated
            # on EOS to fail validation (unless explicitely imported).
            # Disable the SSL/TLS certificate verification for now.
            # Use the approach in PEP476 to disable certificate validation.
            # TODO:
            # ************************** WARNING *****************************
            # This behaviour is considered a *security risk*, so use it
            # temporary until a proper fix is implemented.
            if hasattr(ssl, '_create_unverified_context'):
                return ssl._create_unverified_context()