"""\
RPC request handler Django. Exposed RPC interface functions should be
defined in rpc_interface.py.
"""
__author__ = 'showard@google.com (Steve Howard)'
import inspect
import pydoc
import re
import traceback
import urllib
from autotest_lib.client.common_lib import error
from autotest_lib.frontend.afe import models, rpc_utils
from autotest_lib.frontend.afe import rpcserver_logging
from autotest_lib.frontend.afe.json_rpc import serviceHandler
LOGGING_REGEXPS = [r'.*add_.*',
r'delete_.*',
r'.*remove_.*',
r'modify_.*',
r'create.*',
r'set_.*']
FULL_REGEXP = '(' + '|'.join(LOGGING_REGEXPS) + ')'
COMPILED_REGEXP = re.compile(FULL_REGEXP)
SHARD_RPC_INTERFACE = 'shard_rpc_interface'
COMMON_RPC_INTERFACE = 'common_rpc_interface'
def should_log_message(name):
"""Detect whether to log message.
@param name: the method name.
"""
return COMPILED_REGEXP.match(name)
class RpcMethodHolder(object):
'Dummy class to hold RPC interface methods as attributes.'
class RpcValidator(object):
"""Validate Rpcs handled by RpcHandler.
This validator is introduced to filter RPC's callers. If a caller is not
allowed to call a given RPC, it will be refused by the validator.
"""
def __init__(self, rpc_interface_modules):
self._shard_rpc_methods = []
self._common_rpc_methods = []
for module in rpc_interface_modules:
if COMMON_RPC_INTERFACE in module.__name__:
self._common_rpc_methods = self._grab_name_from(module)
if SHARD_RPC_INTERFACE in module.__name__:
self._shard_rpc_methods = self._grab_name_from(module)
def _grab_name_from(self, module):
"""Grab function name from module and add them to rpc_methods.
@param module: an actual module.
"""
rpc_methods = []
for name in dir(module):
if name.startswith('_'):
continue
attribute = getattr(module, name)
if not inspect.isfunction(attribute):
continue
rpc_methods.append(attribute.func_name)
return rpc_methods
def validate_rpc_only_called_by_master(self, meth_name, remote_ip):
"""Validate whether the method name can be called by remote_ip.
This funcion checks whether the given method (meth_name) belongs to
_shard_rpc_module.
If True, it then checks whether the caller's IP (remote_ip) is autotest
master. An RPCException will be raised if an RPC method from
_shard_rpc_module is called by a caller that is not autotest master.
@param meth_name: the RPC method name which is called.
@param remote_ip: the caller's IP.
"""
if meth_name in self._shard_rpc_methods:
global_afe_ip = rpc_utils.get_ip(rpc_utils.GLOBAL_AFE_HOSTNAME)
if remote_ip != global_afe_ip:
raise error.RPCException(
'Shard RPC %r cannot be called by remote_ip %s. It '
'can only be called by global_afe: %s' % (
meth_name, remote_ip, global_afe_ip))
def encode_validate_result(self, meth_id, err):
"""Encode the return results for validator.
It is used for encoding return response for RPC handler if caller of an
RPC is refused by validator.
@param meth_id: the id of the request for an RPC method.
@param err: The error raised by validator.
@return: a raw http response including the encoded error result. It
will be parsed by service proxy.
"""
error_result = serviceHandler.ServiceHandler.blank_result_dict()
error_result['id'] = meth_id
error_result['err'] = err
error_result['err_traceback'] = traceback.format_exc()
result = self.encode_result(error_result)
return rpc_utils.raw_http_response(result)
class RpcHandler(object):
"""The class to handle Rpc requests."""
def __init__(self, rpc_interface_modules, document_module=None):
"""Initialize an RpcHandler instance.
@param rpc_interface_modules: the included rpc interface modules.
@param document_module: the module includes documentation.
"""
self._rpc_methods = RpcMethodHolder()
self._dispatcher = serviceHandler.ServiceHandler(self._rpc_methods)
self._rpc_validator = RpcValidator(rpc_interface_modules)
# store all methods from interface modules
for module in rpc_interface_modules:
self._grab_methods_from(module)
# get documentation for rpc_interface we can send back to the
# user
if document_module is None:
document_module = rpc_interface_modules[0]
self.html_doc = pydoc.html.document(document_module)
def get_rpc_documentation(self):
"""Get raw response from an http documentation."""
return rpc_utils.raw_http_response(self.html_doc)
def raw_request_data(self, request):
"""Return raw data in request.
@param request: the request to get raw data from.
"""
if request.method == 'POST':
return request.body
return urllib.unquote(request.META['QUERY_STRING'])
def execute_request(self, json_request):
"""Execute a json request.
@param json_request: the json request to be executed.
"""
return self._dispatcher.handleRequest(json_request)
def decode_request(self, json_request):
"""Decode the json request.
@param json_request: the json request to be decoded.
"""
return self._dispatcher.translateRequest(json_request)
def dispatch_request(self, decoded_request):
"""Invoke a RPC call from a decoded request.
@param decoded_request: the json request to be processed and run.
"""
return self._dispatcher.dispatchRequest(decoded_request)
def log_request(self, user, decoded_request, decoded_result,
remote_ip, log_all=False):
"""Log request if required.
@param user: current user.
@param decoded_request: the decoded request.
@param decoded_result: the decoded result.
@param remote_ip: the caller's ip.
@param log_all: whether to log all messages.
"""
if log_all or should_log_message(decoded_request['method']):
msg = '%s| %s:%s %s' % (remote_ip, decoded_request['method'],
user, decoded_request['params'])
if decoded_result['err']:
msg += '\n' + decoded_result['err_traceback']
rpcserver_logging.rpc_logger.error(msg)
else:
rpcserver_logging.rpc_logger.info(msg)
def encode_result(self, results):
"""Encode the result to translated json result.
@param results: the results to be encoded.
"""
return self._dispatcher.translateResult(results)
def handle_rpc_request(self, request):
"""Handle common rpc request and return raw response.
@param request: the rpc request to be processed.
"""
remote_ip = self._get_remote_ip(request)
user = models.User.current_user()
json_request = self.raw_request_data(request)
decoded_request = self.decode_request(json_request)
# Validate whether method can be called by the remote_ip
try:
meth_id = decoded_request['id']
meth_name = decoded_request['method']
self._rpc_validator.validate_rpc_only_called_by_master(
meth_name, remote_ip)
except KeyError:
raise serviceHandler.BadServiceRequest(decoded_request)
except error.RPCException as e:
return self._rpc_validator.encode_validate_result(meth_id, e)
decoded_request['remote_ip'] = remote_ip
decoded_result = self.dispatch_request(decoded_request)
result = self.encode_result(decoded_result)
if rpcserver_logging.LOGGING_ENABLED:
self.log_request(user, decoded_request, decoded_result,
remote_ip)
return rpc_utils.raw_http_response(result)
def handle_jsonp_rpc_request(self, request):
"""Handle the json rpc request and return raw response.
@param request: the rpc request to be handled.
"""
request_data = request.GET['request']
callback_name = request.GET['callback']
# callback_name must be a simple identifier
assert re.search(r'^\w+$', callback_name)
result = self.execute_request(request_data)
padded_result = '%s(%s)' % (callback_name, result)
return rpc_utils.raw_http_response(padded_result,
content_type='text/javascript')
@staticmethod
def _allow_keyword_args(f):
"""\
Decorator to allow a function to take keyword args even though
the RPC layer doesn't support that. The decorated function
assumes its last argument is a dictionary of keyword args and
passes them to the original function as keyword args.
"""
def new_fn(*args):
"""Make the last argument as the keyword args."""
assert args
keyword_args = args[-1]
args = args[:-1]
return f(*args, **keyword_args)
new_fn.func_name = f.func_name
return new_fn
def _grab_methods_from(self, module):
for name in dir(module):
if name.startswith('_'):
continue
attribute = getattr(module, name)
if not inspect.isfunction(attribute):
continue
decorated_function = RpcHandler._allow_keyword_args(attribute)
setattr(self._rpc_methods, name, decorated_function)
def _get_remote_ip(self, request):
"""Get the ip address of a RPC caller.
Returns the IP of the request, accounting for the possibility of
being behind a proxy.
If a Django server is behind a proxy, request.META["REMOTE_ADDR"] will
return the proxy server's IP, not the client's IP.
The proxy server would provide the client's IP in the
HTTP_X_FORWARDED_FOR header.
@param request: django.core.handlers.wsgi.WSGIRequest object.
@return: IP address of remote host as a string.
Empty string if the IP cannot be found.
"""
remote = request.META.get('HTTP_X_FORWARDED_FOR', None)
if remote:
# X_FORWARDED_FOR returns client1, proxy1, proxy2,...
remote = remote.split(',')[0].strip()
else:
remote = request.META.get('REMOTE_ADDR', '')
return remote