# Copyright DataStax, Inc. # # Licensed under the Apache License, Version 2.0 (the "License"); # you may not use this file except in compliance with the License. # You may obtain a copy of the License at # # http://www.apache.org/licenses/LICENSE-2.0 # # Unless required by applicable law or agreed to in writing, software # distributed under the License is distributed on an "AS IS" BASIS, # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. # See the License for the specific language governing permissions and # limitations under the License. from __future__ import absolute_import # to enable import io from stdlib from collections import defaultdict, deque import errno from functools import wraps, partial, total_ordering from heapq import heappush, heappop import io import logging import socket import struct import sys from threading import Thread, Event, RLock, Condition import time import ssl import weakref if 'gevent.monkey' in sys.modules: from gevent.queue import Queue, Empty else: from queue import Queue, Empty # noqa from cassandra import ConsistencyLevel, AuthenticationFailed, OperationTimedOut, ProtocolVersion from cassandra.marshal import int32_pack from cassandra.protocol import (ReadyMessage, AuthenticateMessage, OptionsMessage, StartupMessage, ErrorMessage, CredentialsMessage, QueryMessage, ResultMessage, ProtocolHandler, InvalidRequestException, SupportedMessage, AuthResponseMessage, AuthChallengeMessage, AuthSuccessMessage, ProtocolException, RegisterMessage, ReviseRequestMessage) from cassandra.segment import SegmentCodec, CrcException from cassandra.util import OrderedDict log = logging.getLogger(__name__) segment_codec_no_compression = SegmentCodec() segment_codec_lz4 = None # We use an ordered dictionary and specifically add lz4 before # snappy so that lz4 will be preferred. Changing the order of this # will change the compression preferences for the driver. locally_supported_compressions = OrderedDict() try: import lz4 except ImportError: pass else: # The compress and decompress functions we need were moved from the lz4 to # the lz4.block namespace, so we try both here. try: from lz4 import block as lz4_block except ImportError: lz4_block = lz4 try: lz4_block.compress lz4_block.decompress except AttributeError: raise ImportError( 'lz4 not imported correctly. Imported object should have ' '.compress and and .decompress attributes but does not. ' 'Please file a bug report on JIRA. (Imported object was ' '{lz4_block})'.format(lz4_block=repr(lz4_block)) ) # Cassandra writes the uncompressed message length in big endian order, # but the lz4 lib requires little endian order, so we wrap these # functions to handle that def lz4_compress(byts): # write length in big-endian instead of little-endian return int32_pack(len(byts)) + lz4_block.compress(byts)[4:] def lz4_decompress(byts): # flip from big-endian to little-endian return lz4_block.decompress(byts[3::-1] + byts[4:]) locally_supported_compressions['lz4'] = (lz4_compress, lz4_decompress) segment_codec_lz4 = SegmentCodec(lz4_compress, lz4_decompress) try: import snappy except ImportError: pass else: # work around apparently buggy snappy decompress def decompress(byts): if byts == '\x00': return '' return snappy.decompress(byts) locally_supported_compressions['snappy'] = (snappy.compress, decompress) DRIVER_NAME, DRIVER_VERSION = 'DataStax Python Driver', sys.modules['cassandra'].__version__ PROTOCOL_VERSION_MASK = 0x7f HEADER_DIRECTION_FROM_CLIENT = 0x00 HEADER_DIRECTION_TO_CLIENT = 0x80 HEADER_DIRECTION_MASK = 0x80 frame_header_v1_v2 = struct.Struct('>BbBi') frame_header_v3 = struct.Struct('>BhBi') class EndPoint(object): """ Represents the information to connect to a cassandra node. """ @property def address(self): """ The IP address of the node. This is the RPC address the driver uses when connecting to the node """ raise NotImplementedError() @property def port(self): """ The port of the node. """ raise NotImplementedError() @property def ssl_options(self): """ SSL options specific to this endpoint. """ return None @property def socket_family(self): """ The socket family of the endpoint. """ return socket.AF_UNSPEC def resolve(self): """ Resolve the endpoint to an address/port. This is called only on socket connection. """ raise NotImplementedError() class EndPointFactory(object): cluster = None def configure(self, cluster): """ This is called by the cluster during its initialization. """ self.cluster = cluster return self def create(self, row): """ Create an EndPoint from a system.peers row. """ raise NotImplementedError() @total_ordering class DefaultEndPoint(EndPoint): """ Default EndPoint implementation, basically just an address and port. """ def __init__(self, address, port=9042): self._address = address self._port = port @property def address(self): return self._address @property def port(self): return self._port def resolve(self): return self._address, self._port def __eq__(self, other): return isinstance(other, DefaultEndPoint) and \ self.address == other.address and self.port == other.port def __hash__(self): return hash((self.address, self.port)) def __lt__(self, other): return (self.address, self.port) < (other.address, other.port) def __str__(self): return str("%s:%d" % (self.address, self.port)) def __repr__(self): return "<%s: %s:%d>" % (self.__class__.__name__, self.address, self.port) class DefaultEndPointFactory(EndPointFactory): port = None """ If no port is discovered in the row, this is the default port used for endpoint creation. """ def __init__(self, port=None): self.port = port def create(self, row): # TODO next major... move this class so we don't need this kind of hack from cassandra.metadata import _NodeInfo addr = _NodeInfo.get_broadcast_rpc_address(row) port = _NodeInfo.get_broadcast_rpc_port(row) if port is None: port = self.port if self.port else 9042 # create the endpoint with the translated address # TODO next major, create a TranslatedEndPoint type return DefaultEndPoint( self.cluster.address_translator.translate(addr), port) @total_ordering class SniEndPoint(EndPoint): """SNI Proxy EndPoint implementation.""" def __init__(self, proxy_address, server_name, port=9042): self._proxy_address = proxy_address self._index = 0 self._resolved_address = None # resolved address self._port = port self._server_name = server_name self._ssl_options = {'server_hostname': server_name} @property def address(self): return self._proxy_address @property def port(self): return self._port @property def ssl_options(self): return self._ssl_options def resolve(self): try: resolved_addresses = socket.getaddrinfo(self._proxy_address, self._port, socket.AF_UNSPEC, socket.SOCK_STREAM) except socket.gaierror: log.debug('Could not resolve sni proxy hostname "%s" ' 'with port %d' % (self._proxy_address, self._port)) raise # round-robin pick self._resolved_address = sorted(addr[4][0] for addr in resolved_addresses)[self._index % len(resolved_addresses)] self._index += 1 return self._resolved_address, self._port def __eq__(self, other): return (isinstance(other, SniEndPoint) and self.address == other.address and self.port == other.port and self._server_name == other._server_name) def __hash__(self): return hash((self.address, self.port, self._server_name)) def __lt__(self, other): return ((self.address, self.port, self._server_name) < (other.address, other.port, self._server_name)) def __str__(self): return str("%s:%d:%s" % (self.address, self.port, self._server_name)) def __repr__(self): return "<%s: %s:%d:%s>" % (self.__class__.__name__, self.address, self.port, self._server_name) class SniEndPointFactory(EndPointFactory): def __init__(self, proxy_address, port): self._proxy_address = proxy_address self._port = port def create(self, row): host_id = row.get("host_id") if host_id is None: raise ValueError("No host_id to create the SniEndPoint") return SniEndPoint(self._proxy_address, str(host_id), self._port) def create_from_sni(self, sni): return SniEndPoint(self._proxy_address, sni, self._port) @total_ordering class UnixSocketEndPoint(EndPoint): """ Unix Socket EndPoint implementation. """ def __init__(self, unix_socket_path): self._unix_socket_path = unix_socket_path @property def address(self): return self._unix_socket_path @property def port(self): return None @property def socket_family(self): return socket.AF_UNIX def resolve(self): return self.address, None def __eq__(self, other): return (isinstance(other, UnixSocketEndPoint) and self._unix_socket_path == other._unix_socket_path) def __hash__(self): return hash(self._unix_socket_path) def __lt__(self, other): return self._unix_socket_path < other._unix_socket_path def __str__(self): return str("%s" % (self._unix_socket_path,)) def __repr__(self): return "<%s: %s>" % (self.__class__.__name__, self._unix_socket_path) class _Frame(object): def __init__(self, version, flags, stream, opcode, body_offset, end_pos): self.version = version self.flags = flags self.stream = stream self.opcode = opcode self.body_offset = body_offset self.end_pos = end_pos def __eq__(self, other): # facilitates testing if isinstance(other, _Frame): return (self.version == other.version and self.flags == other.flags and self.stream == other.stream and self.opcode == other.opcode and self.body_offset == other.body_offset and self.end_pos == other.end_pos) return NotImplemented def __str__(self): return "ver({0}); flags({1:04b}); stream({2}); op({3}); offset({4}); len({5})".format(self.version, self.flags, self.stream, self.opcode, self.body_offset, self.end_pos - self.body_offset) NONBLOCKING = (errno.EAGAIN, errno.EWOULDBLOCK) class ConnectionException(Exception): """ An unrecoverable error was hit when attempting to use a connection, or the connection was already closed or defunct. """ def __init__(self, message, endpoint=None): Exception.__init__(self, message) self.endpoint = endpoint @property def host(self): return self.endpoint.address class ConnectionShutdown(ConnectionException): """ Raised when a connection has been marked as defunct or has been closed. """ pass class ProtocolVersionUnsupported(ConnectionException): """ Server rejected startup message due to unsupported protocol version """ def __init__(self, endpoint, startup_version): msg = "Unsupported protocol version on %s: %d" % (endpoint, startup_version) super(ProtocolVersionUnsupported, self).__init__(msg, endpoint) self.startup_version = startup_version class ConnectionBusy(Exception): """ An attempt was made to send a message through a :class:`.Connection` that was already at the max number of in-flight operations. """ pass class ProtocolError(Exception): """ Communication did not match the protocol that this driver expects. """ pass class CrcMismatchException(ConnectionException): pass class ContinuousPagingState(object): """ A class for specifying continuous paging state, only supported starting with DSE_V2. """ num_pages_requested = None """ How many pages we have already requested """ num_pages_received = None """ How many pages we have already received """ max_queue_size = None """ The max queue size chosen by the user via the options """ def __init__(self, max_queue_size): self.num_pages_requested = max_queue_size # the initial query requests max_queue_size self.num_pages_received = 0 self.max_queue_size = max_queue_size class ContinuousPagingSession(object): def __init__(self, stream_id, decoder, row_factory, connection, state): self.stream_id = stream_id self.decoder = decoder self.row_factory = row_factory self.connection = connection self._condition = Condition() self._stop = False self._page_queue = deque() self._state = state self.released = False def on_message(self, result): if isinstance(result, ResultMessage): self.on_page(result) elif isinstance(result, ErrorMessage): self.on_error(result) def on_page(self, result): with self._condition: if self._state: self._state.num_pages_received += 1 self._page_queue.appendleft((result.column_names, result.parsed_rows, None)) self._stop |= result.continuous_paging_last self._condition.notify() if result.continuous_paging_last: self.released = True def on_error(self, error): if isinstance(error, ErrorMessage): error = error.to_exception() log.debug("Got error %s for session %s", error, self.stream_id) with self._condition: self._page_queue.appendleft((None, None, error)) self._stop = True self._condition.notify() self.released = True def results(self): try: self._condition.acquire() while True: while not self._page_queue and not self._stop: self._condition.wait(timeout=5) while self._page_queue: names, rows, err = self._page_queue.pop() if err: raise err self.maybe_request_more() self._condition.release() for row in self.row_factory(names, rows): yield row self._condition.acquire() if self._stop: break finally: try: self._condition.release() except RuntimeError: # This exception happens if the CP results are not entirely consumed # and the session is terminated by the runtime. See PYTHON-1054 pass def maybe_request_more(self): if not self._state: return max_queue_size = self._state.max_queue_size num_in_flight = self._state.num_pages_requested - self._state.num_pages_received space_in_queue = max_queue_size - len(self._page_queue) - num_in_flight log.debug("Session %s from %s, space in CP queue: %s, requested: %s, received: %s, num_in_flight: %s", self.stream_id, self.connection.host, space_in_queue, self._state.num_pages_requested, self._state.num_pages_received, num_in_flight) if space_in_queue >= max_queue_size / 2: self.update_next_pages(space_in_queue) def update_next_pages(self, num_next_pages): try: self._state.num_pages_requested += num_next_pages log.debug("Updating backpressure for session %s from %s", self.stream_id, self.connection.host) with self.connection.lock: self.connection.send_msg(ReviseRequestMessage(ReviseRequestMessage.RevisionType.PAGING_BACKPRESSURE, self.stream_id, next_pages=num_next_pages), self.connection.get_request_id(), self._on_backpressure_response) except ConnectionShutdown as ex: log.debug("Failed to update backpressure for session %s from %s, connection is shutdown", self.stream_id, self.connection.host) self.on_error(ex) def _on_backpressure_response(self, response): if isinstance(response, ResultMessage): log.debug("Paging session %s backpressure updated.", self.stream_id) else: log.error("Failed updating backpressure for session %s from %s: %s", self.stream_id, self.connection.host, response.to_exception() if hasattr(response, 'to_exception') else response) self.on_error(response) def cancel(self): try: log.debug("Canceling paging session %s from %s", self.stream_id, self.connection.host) with self.connection.lock: self.connection.send_msg(ReviseRequestMessage(ReviseRequestMessage.RevisionType.PAGING_CANCEL, self.stream_id), self.connection.get_request_id(), self._on_cancel_response) except ConnectionShutdown: log.debug("Failed to cancel session %s from %s, connection is shutdown", self.stream_id, self.connection.host) with self._condition: self._stop = True self._condition.notify() def _on_cancel_response(self, response): if isinstance(response, ResultMessage): log.debug("Paging session %s canceled.", self.stream_id) else: log.error("Failed canceling streaming session %s from %s: %s", self.stream_id, self.connection.host, response.to_exception() if hasattr(response, 'to_exception') else response) self.released = True def defunct_on_error(f): @wraps(f) def wrapper(self, *args, **kwargs): try: return f(self, *args, **kwargs) except Exception as exc: self.defunct(exc) return wrapper DEFAULT_CQL_VERSION = '3.0.0' class _ConnectionIOBuffer(object): """ Abstraction class to ease the use of the different connection io buffers. With protocol V5 and checksumming, the data is read, validated and copied to another cql frame buffer. """ _io_buffer = None _cql_frame_buffer = None _connection = None _segment_consumed = False def __init__(self, connection): self._io_buffer = io.BytesIO() self._connection = weakref.proxy(connection) @property def io_buffer(self): return self._io_buffer @property def cql_frame_buffer(self): return self._cql_frame_buffer if self.is_checksumming_enabled else \ self._io_buffer def set_checksumming_buffer(self): self.reset_io_buffer() self._cql_frame_buffer = io.BytesIO() @property def is_checksumming_enabled(self): return self._connection._is_checksumming_enabled @property def has_consumed_segment(self): return self._segment_consumed; def readable_io_bytes(self): return self.io_buffer.tell() def readable_cql_frame_bytes(self): return self.cql_frame_buffer.tell() def reset_io_buffer(self): self._io_buffer = io.BytesIO(self._io_buffer.read()) self._io_buffer.seek(0, 2) # 2 == SEEK_END def reset_cql_frame_buffer(self): if self.is_checksumming_enabled: self._cql_frame_buffer = io.BytesIO(self._cql_frame_buffer.read()) self._cql_frame_buffer.seek(0, 2) # 2 == SEEK_END else: self.reset_io_buffer() class Connection(object): CALLBACK_ERR_THREAD_THRESHOLD = 100 in_buffer_size = 4096 out_buffer_size = 4096 cql_version = None no_compact = False protocol_version = ProtocolVersion.MAX_SUPPORTED keyspace = None compression = True _compression_type = None compressor = None decompressor = None endpoint = None ssl_options = None ssl_context = None last_error = None # The current number of operations that are in flight. More precisely, # the number of request IDs that are currently in use. # This includes orphaned requests. in_flight = 0 # Max concurrent requests allowed per connection. This is set optimistically high, allowing # all request ids to be used in protocol version 3+. Normally concurrency would be controlled # at a higher level by the application or concurrent.execute_concurrent. This attribute # is for lower-level integrations that want some upper bound without reimplementing. max_in_flight = 2 ** 15 # A set of available request IDs. When using the v3 protocol or higher, # this will not initially include all request IDs in order to save memory, # but the set will grow if it is exhausted. request_ids = None # Tracks the highest used request ID in order to help with growing the # request_ids set highest_request_id = 0 # Tracks the request IDs which are no longer waited on (timed out), but # cannot be reused yet because the node might still send a response # on this stream orphaned_request_ids = None # Set to true if the orphaned stream ID count cross configured threshold # and the connection will be replaced orphaned_threshold_reached = False # If the number of orphaned streams reaches this threshold, this connection # will become marked and will be replaced with a new connection by the # owning pool (currently, only HostConnection supports this) orphaned_threshold = 3 * max_in_flight // 4 is_defunct = False is_closed = False lock = None user_type_map = None msg_received = False is_unsupported_proto_version = False is_control_connection = False signaled_error = False # used for flagging at the pool level allow_beta_protocol_version = False _current_frame = None _socket = None _socket_impl = socket _check_hostname = False _product_type = None _is_checksumming_enabled = False _on_orphaned_stream_released = None @property def _iobuf(self): # backward compatibility, to avoid any change in the reactors return self._io_buffer.io_buffer def __init__(self, host='127.0.0.1', port=9042, authenticator=None, ssl_options=None, sockopts=None, compression=True, cql_version=None, protocol_version=ProtocolVersion.MAX_SUPPORTED, is_control_connection=False, user_type_map=None, connect_timeout=None, allow_beta_protocol_version=False, no_compact=False, ssl_context=None, on_orphaned_stream_released=None): # TODO next major rename host to endpoint and remove port kwarg. self.endpoint = host if isinstance(host, EndPoint) else DefaultEndPoint(host, port) self.authenticator = authenticator self.ssl_options = ssl_options.copy() if ssl_options else {} self.ssl_context = ssl_context self.sockopts = sockopts self.compression = compression self.cql_version = cql_version self.protocol_version = protocol_version self.is_control_connection = is_control_connection self.user_type_map = user_type_map self.connect_timeout = connect_timeout self.allow_beta_protocol_version = allow_beta_protocol_version self.no_compact = no_compact self._push_watchers = defaultdict(set) self._requests = {} self._io_buffer = _ConnectionIOBuffer(self) self._continuous_paging_sessions = {} self._socket_writable = True self.orphaned_request_ids = set() self._on_orphaned_stream_released = on_orphaned_stream_released if ssl_options: self.ssl_options.update(self.endpoint.ssl_options or {}) elif self.endpoint.ssl_options: self.ssl_options = self.endpoint.ssl_options # PYTHON-1331 # # We always use SSLContext.wrap_socket() now but legacy configs may have other params that were passed to ssl.wrap_socket()... # and either could have 'check_hostname'. Remove these params into a separate map and use them to build an SSLContext if # we need to do so. # # Note the use of pop() here; we are very deliberately removing these params from ssl_options if they're present. After this # operation ssl_options should contain only args needed for the ssl_context.wrap_socket() call. if not self.ssl_context and self.ssl_options: self.ssl_context = self._build_ssl_context_from_options() if protocol_version >= 3: self.max_request_id = min(self.max_in_flight - 1, (2 ** 15) - 1) # Don't fill the deque with 2**15 items right away. Start with some and add # more if needed. initial_size = min(300, self.max_in_flight) self.request_ids = deque(range(initial_size)) self.highest_request_id = initial_size - 1 else: self.max_request_id = min(self.max_in_flight, (2 ** 7) - 1) self.request_ids = deque(range(self.max_request_id + 1)) self.highest_request_id = self.max_request_id self.lock = RLock() self.connected_event = Event() @property def host(self): return self.endpoint.address @property def port(self): return self.endpoint.port @classmethod def initialize_reactor(cls): """ Called once by Cluster.connect(). This should be used by implementations to set up any resources that will be shared across connections. """ pass @classmethod def handle_fork(cls): """ Called after a forking. This should cleanup any remaining reactor state from the parent process. """ pass @classmethod def create_timer(cls, timeout, callback): raise NotImplementedError() @classmethod def factory(cls, endpoint, timeout, *args, **kwargs): """ A factory function which returns connections which have succeeded in connecting and are ready for service (or raises an exception otherwise). """ start = time.time() kwargs['connect_timeout'] = timeout conn = cls(endpoint, *args, **kwargs) elapsed = time.time() - start conn.connected_event.wait(timeout - elapsed) if conn.last_error: if conn.is_unsupported_proto_version: raise ProtocolVersionUnsupported(endpoint, conn.protocol_version) raise conn.last_error elif not conn.connected_event.is_set(): conn.close() raise OperationTimedOut("Timed out creating connection (%s seconds)" % timeout) else: return conn def _build_ssl_context_from_options(self): # Extract a subset of names from self.ssl_options which apply to SSLContext creation ssl_context_opt_names = ['ssl_version', 'cert_reqs', 'check_hostname', 'keyfile', 'certfile', 'ca_certs', 'ciphers'] opts = {k:self.ssl_options.get(k, None) for k in ssl_context_opt_names if k in self.ssl_options} # Python >= 3.10 requires either PROTOCOL_TLS_CLIENT or PROTOCOL_TLS_SERVER so we'll get ahead of things by always # being explicit ssl_version = opts.get('ssl_version', None) or ssl.PROTOCOL_TLS_CLIENT cert_reqs = opts.get('cert_reqs', None) or ssl.CERT_REQUIRED rv = ssl.SSLContext(protocol=int(ssl_version)) rv.check_hostname = bool(opts.get('check_hostname', False)) rv.options = int(cert_reqs) certfile = opts.get('certfile', None) keyfile = opts.get('keyfile', None) if certfile: rv.load_cert_chain(certfile, keyfile) ca_certs = opts.get('ca_certs', None) if ca_certs: rv.load_verify_locations(ca_certs) ciphers = opts.get('ciphers', None) if ciphers: rv.set_ciphers(ciphers) return rv def _wrap_socket_from_context(self): # Extract a subset of names from self.ssl_options which apply to SSLContext.wrap_socket (or at least the parts # of it that don't involve building an SSLContext under the covers) wrap_socket_opt_names = ['server_side', 'do_handshake_on_connect', 'suppress_ragged_eofs', 'server_hostname'] opts = {k:self.ssl_options.get(k, None) for k in wrap_socket_opt_names if k in self.ssl_options} # PYTHON-1186: set the server_hostname only if the SSLContext has # check_hostname enabled and it is not already provided by the EndPoint ssl options #opts['server_hostname'] = self.endpoint.address if (self.ssl_context.check_hostname and 'server_hostname' not in opts): server_hostname = self.endpoint.address opts['server_hostname'] = server_hostname return self.ssl_context.wrap_socket(self._socket, **opts) def _initiate_connection(self, sockaddr): self._socket.connect(sockaddr) # PYTHON-1331 # # Allow implementations specific to an event loop to add additional behaviours def _validate_hostname(self): pass def _get_socket_addresses(self): address, port = self.endpoint.resolve() if hasattr(socket, 'AF_UNIX') and self.endpoint.socket_family == socket.AF_UNIX: return [(socket.AF_UNIX, socket.SOCK_STREAM, 0, None, address)] addresses = socket.getaddrinfo(address, port, self.endpoint.socket_family, socket.SOCK_STREAM) if not addresses: raise ConnectionException("getaddrinfo returned empty list for %s" % (self.endpoint,)) return addresses def _connect_socket(self): sockerr = None addresses = self._get_socket_addresses() for (af, socktype, proto, _, sockaddr) in addresses: try: self._socket = self._socket_impl.socket(af, socktype, proto) if self.ssl_context: self._socket = self._wrap_socket_from_context() self._socket.settimeout(self.connect_timeout) self._initiate_connection(sockaddr) self._socket.settimeout(None) # PYTHON-1331 # # Most checking is done via the check_hostname param on the SSLContext. # Subclasses can add additional behaviours via _validate_hostname() so # run that here. if self._check_hostname: self._validate_hostname() sockerr = None break except socket.error as err: if self._socket: self._socket.close() self._socket = None sockerr = err if sockerr: raise socket.error(sockerr.errno, "Tried connecting to %s. Last error: %s" % ([a[4] for a in addresses], sockerr.strerror or sockerr)) if self.sockopts: for args in self.sockopts: self._socket.setsockopt(*args) def _enable_compression(self): if self._compressor: self.compressor = self._compressor def _enable_checksumming(self): self._io_buffer.set_checksumming_buffer() self._is_checksumming_enabled = True self._segment_codec = segment_codec_lz4 if self.compressor else segment_codec_no_compression log.debug("Enabling protocol checksumming on connection (%s).", id(self)) def close(self): raise NotImplementedError() def defunct(self, exc): with self.lock: if self.is_defunct or self.is_closed: return self.is_defunct = True exc_info = sys.exc_info() # if we are not handling an exception, just use the passed exception, and don't try to format exc_info with the message if any(exc_info): log.debug("Defuncting connection (%s) to %s:", id(self), self.endpoint, exc_info=exc_info) else: log.debug("Defuncting connection (%s) to %s: %s", id(self), self.endpoint, exc) self.last_error = exc self.close() self.error_all_cp_sessions(exc) self.error_all_requests(exc) self.connected_event.set() return exc def error_all_cp_sessions(self, exc): stream_ids = list(self._continuous_paging_sessions.keys()) for stream_id in stream_ids: self._continuous_paging_sessions[stream_id].on_error(exc) def error_all_requests(self, exc): with self.lock: requests = self._requests self._requests = {} if not requests: return new_exc = ConnectionShutdown(str(exc)) def try_callback(cb): try: cb(new_exc) except Exception: log.warning("Ignoring unhandled exception while erroring requests for a " "failed connection (%s) to host %s:", id(self), self.endpoint, exc_info=True) # run first callback from this thread to ensure pool state before leaving cb, _, _ = requests.popitem()[1] try_callback(cb) if not requests: return # additional requests are optionally errored from a separate thread # The default callback and retry logic is fairly expensive -- we don't # want to tie up the event thread when there are many requests def err_all_callbacks(): for cb, _, _ in requests.values(): try_callback(cb) if len(requests) < Connection.CALLBACK_ERR_THREAD_THRESHOLD: err_all_callbacks() else: # daemon thread here because we want to stay decoupled from the cluster TPE # TODO: would it make sense to just have a driver-global TPE? t = Thread(target=err_all_callbacks) t.daemon = True t.start() def get_request_id(self): """ This must be called while self.lock is held. """ try: return self.request_ids.popleft() except IndexError: new_request_id = self.highest_request_id + 1 # in_flight checks should guarantee this assert new_request_id <= self.max_request_id self.highest_request_id = new_request_id return self.highest_request_id def handle_pushed(self, response): log.debug("Message pushed from server: %r", response) for cb in self._push_watchers.get(response.event_type, []): try: cb(response.event_args) except Exception: log.exception("Pushed event handler errored, ignoring:") def send_msg(self, msg, request_id, cb, encoder=ProtocolHandler.encode_message, decoder=ProtocolHandler.decode_message, result_metadata=None): if self.is_defunct: raise ConnectionShutdown("Connection to %s is defunct" % self.endpoint) elif self.is_closed: raise ConnectionShutdown("Connection to %s is closed" % self.endpoint) elif not self._socket_writable: raise ConnectionBusy("Connection %s is overloaded" % self.endpoint) # queue the decoder function with the request # this allows us to inject custom functions per request to encode, decode messages self._requests[request_id] = (cb, decoder, result_metadata) msg = encoder(msg, request_id, self.protocol_version, compressor=self.compressor, allow_beta_protocol_version=self.allow_beta_protocol_version) if self._is_checksumming_enabled: buffer = io.BytesIO() self._segment_codec.encode(buffer, msg) msg = buffer.getvalue() self.push(msg) return len(msg) def wait_for_response(self, msg, timeout=None, **kwargs): return self.wait_for_responses(msg, timeout=timeout, **kwargs)[0] def wait_for_responses(self, *msgs, **kwargs): """ Returns a list of (success, response) tuples. If success is False, response will be an Exception. Otherwise, response will be the normal query response. If fail_on_error was left as True and one of the requests failed, the corresponding Exception will be raised. """ if self.is_closed or self.is_defunct: raise ConnectionShutdown("Connection %s is already closed" % (self, )) timeout = kwargs.get('timeout') fail_on_error = kwargs.get('fail_on_error', True) waiter = ResponseWaiter(self, len(msgs), fail_on_error) # busy wait for sufficient space on the connection messages_sent = 0 while True: needed = len(msgs) - messages_sent with self.lock: available = min(needed, self.max_request_id - self.in_flight + 1) request_ids = [self.get_request_id() for _ in range(available)] self.in_flight += available for i, request_id in enumerate(request_ids): self.send_msg(msgs[messages_sent + i], request_id, partial(waiter.got_response, index=messages_sent + i)) messages_sent += available if messages_sent == len(msgs): break else: if timeout is not None: timeout -= 0.01 if timeout <= 0.0: raise OperationTimedOut() time.sleep(0.01) try: return waiter.deliver(timeout) except OperationTimedOut: raise except Exception as exc: self.defunct(exc) raise def register_watcher(self, event_type, callback, register_timeout=None): """ Register a callback for a given event type. """ self._push_watchers[event_type].add(callback) self.wait_for_response( RegisterMessage(event_list=[event_type]), timeout=register_timeout) def register_watchers(self, type_callback_dict, register_timeout=None): """ Register multiple callback/event type pairs, expressed as a dict. """ for event_type, callback in type_callback_dict.items(): self._push_watchers[event_type].add(callback) self.wait_for_response( RegisterMessage(event_list=type_callback_dict.keys()), timeout=register_timeout) def control_conn_disposed(self): self.is_control_connection = False self._push_watchers = {} @defunct_on_error def _read_frame_header(self): buf = self._io_buffer.cql_frame_buffer.getvalue() pos = len(buf) if pos: version = buf[0] & PROTOCOL_VERSION_MASK if version not in ProtocolVersion.SUPPORTED_VERSIONS: raise ProtocolError("This version of the driver does not support protocol version %d" % version) frame_header = frame_header_v3 if version >= 3 else frame_header_v1_v2 # this frame header struct is everything after the version byte header_size = frame_header.size + 1 if pos >= header_size: flags, stream, op, body_len = frame_header.unpack_from(buf, 1) if body_len < 0: raise ProtocolError("Received negative body length: %r" % body_len) self._current_frame = _Frame(version, flags, stream, op, header_size, body_len + header_size) return pos @defunct_on_error def _process_segment_buffer(self): readable_bytes = self._io_buffer.readable_io_bytes() if readable_bytes >= self._segment_codec.header_length_with_crc: try: self._io_buffer.io_buffer.seek(0) segment_header = self._segment_codec.decode_header(self._io_buffer.io_buffer) if readable_bytes >= segment_header.segment_length: segment = self._segment_codec.decode(self._iobuf, segment_header) self._io_buffer._segment_consumed = True self._io_buffer.cql_frame_buffer.write(segment.payload) else: # not enough data to read the segment. reset the buffer pointer at the # beginning to not lose what we previously read (header). self._io_buffer._segment_consumed = False self._io_buffer.io_buffer.seek(0) except CrcException as exc: # re-raise an exception that inherits from ConnectionException raise CrcMismatchException(str(exc), self.endpoint) else: self._io_buffer._segment_consumed = False def process_io_buffer(self): while True: if self._is_checksumming_enabled and self._io_buffer.readable_io_bytes(): self._process_segment_buffer() self._io_buffer.reset_io_buffer() if self._is_checksumming_enabled and not self._io_buffer.has_consumed_segment: # We couldn't read an entire segment from the io buffer, so return # control to allow more bytes to be read off the wire return if not self._current_frame: pos = self._read_frame_header() else: pos = self._io_buffer.readable_cql_frame_bytes() if not self._current_frame or pos < self._current_frame.end_pos: if self._is_checksumming_enabled and self._io_buffer.readable_io_bytes(): # We have a multi-segments message and we need to read more # data to complete the current cql frame continue # we don't have a complete header yet or we # already saw a header, but we don't have a # complete message yet return else: frame = self._current_frame self._io_buffer.cql_frame_buffer.seek(frame.body_offset) msg = self._io_buffer.cql_frame_buffer.read(frame.end_pos - frame.body_offset) self.process_msg(frame, msg) self._io_buffer.reset_cql_frame_buffer() self._current_frame = None @defunct_on_error def process_msg(self, header, body): self.msg_received = True stream_id = header.stream if stream_id < 0: callback = None decoder = ProtocolHandler.decode_message result_metadata = None else: if stream_id in self._continuous_paging_sessions: paging_session = self._continuous_paging_sessions[stream_id] callback = paging_session.on_message decoder = paging_session.decoder result_metadata = None else: need_notify_of_release = False with self.lock: if stream_id in self.orphaned_request_ids: self.in_flight -= 1 self.orphaned_request_ids.remove(stream_id) need_notify_of_release = True if need_notify_of_release and self._on_orphaned_stream_released: self._on_orphaned_stream_released() try: callback, decoder, result_metadata = self._requests.pop(stream_id) # This can only happen if the stream_id was # removed due to an OperationTimedOut except KeyError: with self.lock: self.request_ids.append(stream_id) return try: response = decoder(header.version, self.user_type_map, stream_id, header.flags, header.opcode, body, self.decompressor, result_metadata) except Exception as exc: log.exception("Error decoding response from Cassandra. " "%s; buffer: %r", header, self._iobuf.getvalue()) if callback is not None: callback(exc) self.defunct(exc) return try: if stream_id >= 0: if isinstance(response, ProtocolException): if 'unsupported protocol version' in response.message: self.is_unsupported_proto_version = True else: log.error("Closing connection %s due to protocol error: %s", self, response.summary_msg()) self.defunct(response) if callback is not None: callback(response) else: self.handle_pushed(response) except Exception: log.exception("Callback handler errored, ignoring:") # done after callback because the callback might signal this as a paging session if stream_id >= 0: if stream_id in self._continuous_paging_sessions: if self._continuous_paging_sessions[stream_id].released: self.remove_continuous_paging_session(stream_id) else: with self.lock: self.request_ids.append(stream_id) def new_continuous_paging_session(self, stream_id, decoder, row_factory, state): session = ContinuousPagingSession(stream_id, decoder, row_factory, self, state) self._continuous_paging_sessions[stream_id] = session return session def remove_continuous_paging_session(self, stream_id): try: self._continuous_paging_sessions.pop(stream_id) with self.lock: log.debug("Returning cp session stream id %s", stream_id) self.request_ids.append(stream_id) except KeyError: pass @defunct_on_error def _send_options_message(self): log.debug("Sending initial options message for new connection (%s) to %s", id(self), self.endpoint) self.send_msg(OptionsMessage(), self.get_request_id(), self._handle_options_response) @defunct_on_error def _handle_options_response(self, options_response): if self.is_defunct: return if not isinstance(options_response, SupportedMessage): if isinstance(options_response, ConnectionException): raise options_response else: log.error("Did not get expected SupportedMessage response; " "instead, got: %s", options_response) raise ConnectionException("Did not get expected SupportedMessage " "response; instead, got: %s" % (options_response,)) log.debug("Received options response on new connection (%s) from %s", id(self), self.endpoint) supported_cql_versions = options_response.cql_versions remote_supported_compressions = options_response.options['COMPRESSION'] self._product_type = options_response.options.get('PRODUCT_TYPE', [None])[0] if self.cql_version: if self.cql_version not in supported_cql_versions: raise ProtocolError( "cql_version %r is not supported by remote (w/ native " "protocol). Supported versions: %r" % (self.cql_version, supported_cql_versions)) else: self.cql_version = supported_cql_versions[0] self._compressor = None compression_type = None if self.compression: overlap = (set(locally_supported_compressions.keys()) & set(remote_supported_compressions)) if len(overlap) == 0: log.debug("No available compression types supported on both ends." " locally supported: %r. remotely supported: %r", locally_supported_compressions.keys(), remote_supported_compressions) else: compression_type = None if isinstance(self.compression, str): # the user picked a specific compression type ('snappy' or 'lz4') if self.compression not in remote_supported_compressions: raise ProtocolError( "The requested compression type (%s) is not supported by the Cassandra server at %s" % (self.compression, self.endpoint)) compression_type = self.compression else: # our locally supported compressions are ordered to prefer # lz4, if available for k in locally_supported_compressions.keys(): if k in overlap: compression_type = k break # If snappy compression is selected with v5+checksumming, the connection # will fail with OTO. Only lz4 is supported if (compression_type == 'snappy' and ProtocolVersion.has_checksumming_support(self.protocol_version)): log.debug("Snappy compression is not supported with protocol version %s and " "checksumming. Consider installing lz4. Disabling compression.", self.protocol_version) compression_type = None else: # set the decompressor here, but set the compressor only after # a successful Ready message self._compression_type = compression_type self._compressor, self.decompressor = \ locally_supported_compressions[compression_type] self._send_startup_message(compression_type, no_compact=self.no_compact) @defunct_on_error def _send_startup_message(self, compression=None, no_compact=False): log.debug("Sending StartupMessage on %s", self) opts = {'DRIVER_NAME': DRIVER_NAME, 'DRIVER_VERSION': DRIVER_VERSION} if compression: opts['COMPRESSION'] = compression if no_compact: opts['NO_COMPACT'] = 'true' sm = StartupMessage(cqlversion=self.cql_version, options=opts) self.send_msg(sm, self.get_request_id(), cb=self._handle_startup_response) log.debug("Sent StartupMessage on %s", self) @defunct_on_error def _handle_startup_response(self, startup_response, did_authenticate=False): if self.is_defunct: return if isinstance(startup_response, ReadyMessage): if self.authenticator: log.warning("An authentication challenge was not sent, " "this is suspicious because the driver expects " "authentication (configured authenticator = %s)", self.authenticator.__class__.__name__) log.debug("Got ReadyMessage on new connection (%s) from %s", id(self), self.endpoint) self._enable_compression() if ProtocolVersion.has_checksumming_support(self.protocol_version): self._enable_checksumming() self.connected_event.set() elif isinstance(startup_response, AuthenticateMessage): log.debug("Got AuthenticateMessage on new connection (%s) from %s: %s", id(self), self.endpoint, startup_response.authenticator) if self.authenticator is None: log.error("Failed to authenticate to %s. If you are trying to connect to a DSE cluster, " "consider using TransitionalModePlainTextAuthProvider " "if DSE authentication is configured with transitional mode" % (self.host,)) raise AuthenticationFailed('Remote end requires authentication') self._enable_compression() if ProtocolVersion.has_checksumming_support(self.protocol_version): self._enable_checksumming() if isinstance(self.authenticator, dict): log.debug("Sending credentials-based auth response on %s", self) cm = CredentialsMessage(creds=self.authenticator) callback = partial(self._handle_startup_response, did_authenticate=True) self.send_msg(cm, self.get_request_id(), cb=callback) else: log.debug("Sending SASL-based auth response on %s", self) self.authenticator.server_authenticator_class = startup_response.authenticator initial_response = self.authenticator.initial_response() initial_response = "" if initial_response is None else initial_response self.send_msg(AuthResponseMessage(initial_response), self.get_request_id(), self._handle_auth_response) elif isinstance(startup_response, ErrorMessage): log.debug("Received ErrorMessage on new connection (%s) from %s: %s", id(self), self.endpoint, startup_response.summary_msg()) if did_authenticate: raise AuthenticationFailed( "Failed to authenticate to %s: %s" % (self.endpoint, startup_response.summary_msg())) else: raise ConnectionException( "Failed to initialize new connection to %s: %s" % (self.endpoint, startup_response.summary_msg())) elif isinstance(startup_response, ConnectionShutdown): log.debug("Connection to %s was closed during the startup handshake", (self.endpoint)) raise startup_response else: msg = "Unexpected response during Connection setup: %r" log.error(msg, startup_response) raise ProtocolError(msg % (startup_response,)) @defunct_on_error def _handle_auth_response(self, auth_response): if self.is_defunct: return if isinstance(auth_response, AuthSuccessMessage): log.debug("Connection %s successfully authenticated", self) self.authenticator.on_authentication_success(auth_response.token) if self._compressor: self.compressor = self._compressor self.connected_event.set() elif isinstance(auth_response, AuthChallengeMessage): response = self.authenticator.evaluate_challenge(auth_response.challenge) msg = AuthResponseMessage("" if response is None else response) log.debug("Responding to auth challenge on %s", self) self.send_msg(msg, self.get_request_id(), self._handle_auth_response) elif isinstance(auth_response, ErrorMessage): log.debug("Received ErrorMessage on new connection (%s) from %s: %s", id(self), self.endpoint, auth_response.summary_msg()) raise AuthenticationFailed( "Failed to authenticate to %s: %s" % (self.endpoint, auth_response.summary_msg())) elif isinstance(auth_response, ConnectionShutdown): log.debug("Connection to %s was closed during the authentication process", self.endpoint) raise auth_response else: msg = "Unexpected response during Connection authentication to %s: %r" log.error(msg, self.endpoint, auth_response) raise ProtocolError(msg % (self.endpoint, auth_response)) def set_keyspace_blocking(self, keyspace): if not keyspace or keyspace == self.keyspace: return query = QueryMessage(query='USE "%s"' % (keyspace,), consistency_level=ConsistencyLevel.ONE) try: result = self.wait_for_response(query) except InvalidRequestException as ire: # the keyspace probably doesn't exist raise ire.to_exception() except Exception as exc: conn_exc = ConnectionException( "Problem while setting keyspace: %r" % (exc,), self.endpoint) self.defunct(conn_exc) raise conn_exc if isinstance(result, ResultMessage): self.keyspace = keyspace else: conn_exc = ConnectionException( "Problem while setting keyspace: %r" % (result,), self.endpoint) self.defunct(conn_exc) raise conn_exc def set_keyspace_async(self, keyspace, callback): """ Use this in order to avoid deadlocking the event loop thread. When the operation completes, `callback` will be called with two arguments: this connection and an Exception if an error occurred, otherwise :const:`None`. This method will always increment :attr:`.in_flight` attribute, even if it doesn't need to make a request, just to maintain an ":attr:`.in_flight` is incremented" invariant. """ # Here we increment in_flight unconditionally, whether we need to issue # a request or not. This is bad, but allows callers -- specifically # _set_keyspace_for_all_conns -- to assume that we increment # self.in_flight during this call. This allows the passed callback to # safely call HostConnection{Pool,}.return_connection on this # Connection. # # We use a busy wait on the lock here because: # - we'll only spin if the connection is at max capacity, which is very # unlikely for a set_keyspace call # - it allows us to avoid signaling a condition every time a request completes while True: with self.lock: if self.in_flight < self.max_request_id: self.in_flight += 1 break time.sleep(0.001) if not keyspace or keyspace == self.keyspace: callback(self, None) return query = QueryMessage(query='USE "%s"' % (keyspace,), consistency_level=ConsistencyLevel.ONE) def process_result(result): if isinstance(result, ResultMessage): self.keyspace = keyspace callback(self, None) elif isinstance(result, InvalidRequestException): callback(self, result.to_exception()) else: callback(self, self.defunct(ConnectionException( "Problem while setting keyspace: %r" % (result,), self.endpoint))) # We've incremented self.in_flight above, so we "have permission" to # acquire a new request id request_id = self.get_request_id() self.send_msg(query, request_id, process_result) @property def is_idle(self): return not self.msg_received def reset_idle(self): self.msg_received = False def __str__(self): status = "" if self.is_defunct: status = " (defunct)" elif self.is_closed: status = " (closed)" return "<%s(%r) %s%s>" % (self.__class__.__name__, id(self), self.endpoint, status) __repr__ = __str__ class ResponseWaiter(object): def __init__(self, connection, num_responses, fail_on_error): self.connection = connection self.pending = num_responses self.fail_on_error = fail_on_error self.error = None self.responses = [None] * num_responses self.event = Event() def got_response(self, response, index): with self.connection.lock: self.connection.in_flight -= 1 if isinstance(response, Exception): if hasattr(response, 'to_exception'): response = response.to_exception() if self.fail_on_error: self.error = response self.event.set() else: self.responses[index] = (False, response) else: if not self.fail_on_error: self.responses[index] = (True, response) else: self.responses[index] = response self.pending -= 1 if not self.pending: self.event.set() def deliver(self, timeout=None): """ If fail_on_error was set to False, a list of (success, response) tuples will be returned. If success is False, response will be an Exception. Otherwise, response will be the normal query response. If fail_on_error was left as True and one of the requests failed, the corresponding Exception will be raised. Otherwise, the normal response will be returned. """ self.event.wait(timeout) if self.error: raise self.error elif not self.event.is_set(): raise OperationTimedOut() else: return self.responses class HeartbeatFuture(object): def __init__(self, connection, owner): self._exception = None self._event = Event() self.connection = connection self.owner = owner log.debug("Sending options message heartbeat on idle connection (%s) %s", id(connection), connection.endpoint) with connection.lock: if connection.in_flight < connection.max_request_id: connection.in_flight += 1 connection.send_msg(OptionsMessage(), connection.get_request_id(), self._options_callback) else: self._exception = Exception("Failed to send heartbeat because connection 'in_flight' exceeds threshold") self._event.set() def wait(self, timeout): self._event.wait(timeout) if self._event.is_set(): if self._exception: raise self._exception else: raise OperationTimedOut("Connection heartbeat timeout after %s seconds" % (timeout,), self.connection.endpoint) def _options_callback(self, response): if isinstance(response, SupportedMessage): log.debug("Received options response on connection (%s) from %s", id(self.connection), self.connection.endpoint) else: if isinstance(response, ConnectionException): self._exception = response else: self._exception = ConnectionException("Received unexpected response to OptionsMessage: %s" % (response,)) self._event.set() class ConnectionHeartbeat(Thread): def __init__(self, interval_sec, get_connection_holders, timeout): Thread.__init__(self, name="Connection heartbeat") self._interval = interval_sec self._timeout = timeout self._get_connection_holders = get_connection_holders self._shutdown_event = Event() self.daemon = True self.start() class ShutdownException(Exception): pass def run(self): self._shutdown_event.wait(self._interval) while not self._shutdown_event.is_set(): start_time = time.time() futures = [] failed_connections = [] try: for connections, owner in [(o.get_connections(), o) for o in self._get_connection_holders()]: for connection in connections: self._raise_if_stopped() if not (connection.is_defunct or connection.is_closed): if connection.is_idle: try: futures.append(HeartbeatFuture(connection, owner)) except Exception as e: log.warning("Failed sending heartbeat message on connection (%s) to %s", id(connection), connection.endpoint) failed_connections.append((connection, owner, e)) else: connection.reset_idle() else: log.debug("Cannot send heartbeat message on connection (%s) to %s", id(connection), connection.endpoint) # make sure the owner sees this defunt/closed connection owner.return_connection(connection) self._raise_if_stopped() # Wait max `self._timeout` seconds for all HeartbeatFutures to complete timeout = self._timeout start_time = time.time() for f in futures: self._raise_if_stopped() connection = f.connection try: f.wait(timeout) # TODO: move this, along with connection locks in pool, down into Connection with connection.lock: connection.in_flight -= 1 connection.reset_idle() except Exception as e: log.warning("Heartbeat failed for connection (%s) to %s", id(connection), connection.endpoint) failed_connections.append((f.connection, f.owner, e)) timeout = self._timeout - (time.time() - start_time) for connection, owner, exc in failed_connections: self._raise_if_stopped() if not connection.is_control_connection: # Only HostConnection supports shutdown_on_error owner.shutdown_on_error = True connection.defunct(exc) owner.return_connection(connection) except self.ShutdownException: pass except Exception: log.error("Failed connection heartbeat", exc_info=True) elapsed = time.time() - start_time self._shutdown_event.wait(max(self._interval - elapsed, 0.01)) def stop(self): self._shutdown_event.set() self.join() def _raise_if_stopped(self): if self._shutdown_event.is_set(): raise self.ShutdownException() class Timer(object): canceled = False def __init__(self, timeout, callback): self.end = time.time() + timeout self.callback = callback def __lt__(self, other): return self.end < other.end def cancel(self): self.canceled = True def finish(self, time_now): if self.canceled: return True if time_now >= self.end: self.callback() return True return False class TimerManager(object): def __init__(self): self._queue = [] self._new_timers = [] def add_timer(self, timer): """ called from client thread with a Timer object """ self._new_timers.append((timer.end, timer)) def service_timeouts(self): """ run callbacks on all expired timers Called from the event thread :return: next end time, or None """ queue = self._queue if self._new_timers: new_timers = self._new_timers while new_timers: heappush(queue, new_timers.pop()) if queue: now = time.time() while queue: try: timer = queue[0][1] if timer.finish(now): heappop(queue) else: return timer.end except Exception: log.exception("Exception while servicing timeout callback: ") @property def next_timeout(self): try: return self._queue[0][0] except IndexError: pass