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# Copyright (c) 2014, Arista Networks, Inc.
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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_HTTPS_LOCAL_PORT = 8443
DEFAULT_HTTP_PATH = '/command-api'
DEFAULT_UNIX_SOCKET = '/var/run/command-api.sock'
[docs]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)
[docs]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)
[docs]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()
[docs] 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
[docs]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)
[docs]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
[docs] def connect(self):
self.sock = socket.socket(socket.AF_UNIX, socket.SOCK_STREAM)
self.sock.settimeout(self.timeout)
self.sock.connect(self.path)
[docs]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)
[docs]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)
[docs]class HTTPSCertConnection(HTTPSConnection):
""" Class to make a HTTPS connection, with support
for full client-based SSL Authentication.
"""
def __init__(self, path, host, port, key_file, cert_file, ca_file,
timeout=None):
HTTPSConnection.__init__(self, host, key_file=key_file,
cert_file=cert_file)
self.key_file = key_file
self.cert_file = cert_file
self.ca_file = ca_file
self.timeout = timeout
self.path = path
self.port = port
def __str__(self):
return 'https://%s:%s/%s - %s,%s' % (self.host, self.port, self.path,
self.key_file, self.cert_file)
def __repr__(self):
return 'https://%s:%s/%s - %s,%s' % (self.host, self.port, self.path,
self.key_file, self.cert_file)
[docs] def connect(self):
""" Connect to a host on a given (SSL) port.
If ca_file is pointing somewhere, use it
to check Server Certificate.
Redefined/copied and extended from httplib.py:1105 (Python 2.6.x).
This is needed to pass cert_reqs=ssl.CERT_REQUIRED as parameter
to ssl.wrap_socket(), which forces SSL to check server certificate
against our client certificate.
"""
sock = socket.create_connection((self.host, self.port), self.timeout)
if self._tunnel_host:
self.sock = sock
self._tunnel()
# If there's no CA File, don't force Server Certificate Check
if self.ca_file:
self.sock = ssl.wrap_socket(sock, self.key_file, self.cert_file,
ca_certs=self.ca_file,
cert_reqs=ssl.CERT_REQUIRED)
else:
self.sock = ssl.wrap_socket(sock, self.key_file,
self.cert_file,
cert_reqs=ssl.CERT_NONE)
[docs]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)
[docs] 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
"""
_auth_text = '{}:{}'.format(username, password)
# Work around for Python 2.7/3.x compatibility
if int(sys.version[0]) > 2:
# For Python 3.x
_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(_auth_text)
self._auth = str(_auth).replace('\n', '')
_LOGGER.debug('Autentication string is: {}:***'.format(username))
[docs] 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}
streaming = False
if 'autoComplete' in kwargs:
params['autoComplete'] = kwargs['autoComplete']
if 'expandAliases' in kwargs:
params['expandAliases'] = kwargs['expandAliases']
if 'streaming' in kwargs:
streaming = kwargs['streaming']
return json.dumps({'jsonrpc': '2.0', 'method': 'runCmds',
'params': params, 'id': str(reqid),
'streaming': streaming})
[docs] 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))
if response.status == 401:
raise ConnectionError(str(self), '%s. %s' % (response.reason,
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) as exc:
_LOGGER.exception(exc)
self.socket_error = exc
self.error = exc
error_msg = 'Socket error during eAPI connection: %s' % str(exc)
raise ConnectionError(str(self), error_msg)
except ValueError as exc:
_LOGGER.exception(exc)
self.socket_error = None
self.error = exc
raise ConnectionError(str(self), 'unable to connect to eAPI')
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
[docs] 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
[docs]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)
[docs]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)
[docs]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)
[docs]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)
[docs] 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 explicitly 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()
[docs]class HttpsEapiCertConnection(EapiConnection):
def __init__(self, host, port=None, path=None, key_file=None,
cert_file=None, ca_file=None, timeout=60, **kwargs):
if key_file is None or cert_file is None:
raise ValueError("For https_cert connections both a key_file and "
"cert_file are required. A ca_file is also "
"recommended")
super(HttpsEapiCertConnection, self).__init__()
port = port or DEFAULT_HTTPS_PORT
path = path or DEFAULT_HTTP_PATH
self.transport = HTTPSCertConnection(path, host, int(port),
key_file=key_file,
cert_file=cert_file,
ca_file=ca_file, timeout=timeout)