X-Git-Url: https://gerrit.fd.io/r/gitweb?a=blobdiff_plain;f=src%2Fvpp-api%2Fpython%2Fvpp_papi%2Fvpp_transport_socket.py;h=c82b8c365a17dcb7b4ef011533d7960767ee8678;hb=400ce717ac043ceec404103dbaa87dd17d92feb7;hp=b00d15de873ff0acebf8512944716df872eda085;hpb=2233f85694c92a7f2c106ed4e6c50ad145dfb4e2;p=vpp.git diff --git a/src/vpp-api/python/vpp_papi/vpp_transport_socket.py b/src/vpp-api/python/vpp_papi/vpp_transport_socket.py index b00d15de873..c82b8c365a1 100644 --- a/src/vpp-api/python/vpp_papi/vpp_transport_socket.py +++ b/src/vpp-api/python/vpp_papi/vpp_transport_socket.py @@ -6,30 +6,37 @@ import struct import threading import select import multiprocessing -try: - import queue as queue -except ImportError: - import Queue as queue +import queue import logging +logger = logging.getLogger('vpp_papi.transport') +logger.addHandler(logging.NullHandler()) + class VppTransportSocketIOError(IOError): + # TODO: Document different values of error number (first numeric argument). pass -class VppTransport(object): +class VppTransport: VppTransportSocketIOError = VppTransportSocketIOError def __init__(self, parent, read_timeout, server_address): self.connected = False - self.read_timeout = read_timeout if read_timeout > 0 else 1 + self.read_timeout = read_timeout if read_timeout > 0 else None self.parent = parent self.server_address = server_address self.header = struct.Struct('>QII') self.message_table = {} + # These queues can be accessed async. + # They are always up, but replaced on connect. + # TODO: Use multiprocessing.Pipe instead of multiprocessing.Queue + # if possible. self.sque = multiprocessing.Queue() self.q = multiprocessing.Queue() - self.message_thread = None # Will be set on connect(). + # The following fields are set in connect(). + self.message_thread = None + self.socket = None def msg_thread_func(self): while True: @@ -68,11 +75,12 @@ class VppTransport(object): 2, 'Unknown response from select') def connect(self, name, pfx, msg_handler, rx_qlen): + # TODO: Reorder the actions and add "roll-backs", + # to restore clean disconnect state when failure happens durng connect. if self.message_thread is not None: - raise RuntimeError( - "PAPI socket transport connect: You need to disconnect first.") - self.message_thread = threading.Thread(target=self.msg_thread_func) + raise VppTransportSocketIOError( + 1, "PAPI socket transport connect: Need to disconnect first.") # Create a UDS socket self.socket = socket.socket(socket.AF_UNIX, socket.SOCK_STREAM) @@ -82,10 +90,22 @@ class VppTransport(object): try: self.socket.connect(self.server_address) except socket.error as msg: - logging.error("{} on socket {}".format(msg, self.server_address)) - raise + # logging.error("{} on socket {}".format(msg, self.server_address)) + raise msg self.connected = True + + # Queues' feeder threads from previous connect may still be sending. + # Close and join to avoid any errors. + self.sque.close() + self.q.close() + self.sque.join_thread() + self.q.join_thread() + # Finally safe to replace. + self.sque = multiprocessing.Queue() + self.q = multiprocessing.Queue() + self.message_thread = threading.Thread(target=self.msg_thread_func) + # Initialise sockclnt_create sockclnt_create = self.parent.messages['sockclnt_create'] sockclnt_create_reply = self.parent.messages['sockclnt_create_reply'] @@ -98,12 +118,13 @@ class VppTransport(object): msg = self._read() hdr, length = self.parent.header.unpack(msg, 0) if hdr.msgid != 16: + # TODO: Add first numeric argument. raise VppTransportSocketIOError('Invalid reply message') r, length = sockclnt_create_reply.unpack(msg) self.socket_index = r.index for m in r.message_table: - n = m.name.rstrip(b'\x00\x13') + n = m.name self.message_table[n] = m.index self.message_thread.daemon = True @@ -112,18 +133,31 @@ class VppTransport(object): return 0 def disconnect(self): - # TODO: Should we detect if user forgot to connect first? + # TODO: Support repeated disconnect calls, recommend users to call + # disconnect when they are not sure what the state is after failures. + # TODO: Any volunteer for comprehensive docstrings? rv = 0 - try: # Might fail, if VPP closes socket before packet makes it out + try: + # Might fail, if VPP closes socket before packet makes it out, + # or if there was a failure during connect(). + # TODO: manually build message so that .disconnect releases server-side resources rv = self.parent.api.sockclnt_delete(index=self.socket_index) - except IOError: + except (IOError, self.parent.VPPApiError): pass self.connected = False - self.socket.close() - self.sque.put(True) # Terminate listening thread - self.message_thread.join() - # Allow additional connect() calls. + if self.socket is not None: + self.socket.close() + if self.sque is not None: + self.sque.put(True) # Terminate listening thread + if self.message_thread is not None and self.message_thread.is_alive(): + # Allow additional connect() calls. + self.message_thread.join() + # Wipe message table, VPP can be restarted with different plugins. + self.message_table = {} + # Collect garbage. self.message_thread = None + self.socket = None + # Queues will be collected after connect replaces them. return rv def suspend(self): @@ -154,37 +188,49 @@ class VppTransport(object): # Send header header = self.header.pack(0, len(buf), 0) - n = self.socket.send(header) - n = self.socket.send(buf) + try: + self.socket.sendall(header) + self.socket.sendall(buf) + except socket.error as err: + raise VppTransportSocketIOError(1, 'Sendall error: {err!r}'.format( + err=err)) + + def _read_fixed(self, size): + """Repeat receive until fixed size is read. Return empty on error.""" + buf = bytearray(size) + view = memoryview(buf) + left = size + while 1: + got = self.socket.recv_into(view, left) + if got <= 0: + # Read error. + return "" + if got >= left: + # TODO: Raise if got > left? + break + left -= got + view = view[got:] + return buf def _read(self): - hdr = self.socket.recv(16) + """Read single complete message, return it or empty on error.""" + hdr = self._read_fixed(16) if not hdr: return - (_, l, _) = self.header.unpack(hdr) # If at head of message + (_, hdrlen, _) = self.header.unpack(hdr) # If at head of message # Read rest of message - msg = self.socket.recv(l) - if l > len(msg): - nbytes = len(msg) - buf = bytearray(l) - view = memoryview(buf) - view[:nbytes] = msg - view = view[nbytes:] - left = l - nbytes - while left: - nbytes = self.socket.recv_into(view, left) - view = view[nbytes:] - left -= nbytes - return buf - if l == len(msg): + msg = self._read_fixed(hdrlen) + if hdrlen == len(msg): return msg raise VppTransportSocketIOError(1, 'Unknown socket read error') - def read(self): + def read(self, timeout=None): if not self.connected: raise VppTransportSocketIOError(1, 'Not connected') + if timeout is None: + timeout = self.read_timeout try: - return self.q.get(True, self.read_timeout) + return self.q.get(True, timeout) except queue.Empty: return None