from __future__ import print_function
import sys, os, logging, collections, struct, json, threading, glob
+import atexit, Queue
+
logging.basicConfig(level=logging.DEBUG)
import vpp_api
def eprint(*args, **kwargs):
+ """Print critical diagnostics to stderr."""
print(*args, file=sys.stderr, **kwargs)
+def vpp_atexit(self):
+ """Clean up VPP connection on shutdown."""
+ if self.connected:
+ eprint ('Cleaning up VPP on exit')
+ self.disconnect()
+
+
+class Empty(object):
+ pass
+
+
+class FuncWrapper(object):
+ def __init__(self, func):
+ self._func = func
+ self.__name__ = func.__name__
+
+ def __call__(self, **kwargs):
+ return self._func(**kwargs)
+
+
class VPP():
- def __init__(self, apifiles = None, testmode = False):
+ """VPP interface.
+
+ This class provides the APIs to VPP. The APIs are loaded
+ from provided .api.json files and makes functions accordingly.
+ These functions are documented in the VPP .api files, as they
+ are dynamically created.
+
+ Additionally, VPP can send callback messages; this class
+ provides a means to register a callback function to receive
+ these messages in a background thread.
+ """
+ def __init__(self, apifiles = None, testmode = False, async_thread = True):
+ """Create a VPP API object.
+
+ apifiles is a list of files containing API
+ descriptions that will be loaded - methods will be
+ dynamically created reflecting these APIs. If not
+ provided this will load the API files from VPP's
+ default install location.
+ """
self.messages = {}
self.id_names = []
self.id_msgdef = []
self.buffersize = 10000
self.connected = False
self.header = struct.Struct('>HI')
- self.results = {}
- self.timeout = 5
- self.apifile = []
+ self.apifiles = []
+ self.event_callback = None
+ self.message_queue = Queue.Queue()
+ self.read_timeout = 0
+ self.vpp_api = vpp_api
+ if async_thread:
+ self.event_thread = threading.Thread(target=self.thread_msg_handler)
+ self.event_thread.daemon = True
+ self.event_thread.start()
if not apifiles:
# Pick up API definitions from default directory
apifiles = glob.glob('/usr/share/vpp/api/*.api.json')
for file in apifiles:
- self.apifile.append(file)
with open(file) as apidef_file:
api = json.load(apidef_file)
for t in api['types']:
for m in api['messages']:
self.add_message(m[0], m[1:])
+ self.apifiles = apifiles
# Basic sanity check
if len(self.messages) == 0 and not testmode:
raise ValueError(1, 'Missing JSON message definitions')
+ # Make sure we allow VPP to clean up the message rings.
+ atexit.register(vpp_atexit, self)
class ContextId(object):
+ """Thread-safe provider of unique context IDs."""
def __init__(self):
self.context = 0
+ self.lock = threading.Lock()
def __call__(self):
- self.context += 1
- return self.context
+ """Get a new unique (or, at least, not recently used) context."""
+ with self.lock:
+ self.context += 1
+ return self.context
get_context = ContextId()
def status(self):
+ """Debug function: report current VPP API status to stdout."""
print('Connected') if self.connected else print('Not Connected')
- print('Read API definitions from', self.apifile)
+ print('Read API definitions from', ', '.join(self.apifiles))
def __struct (self, t, n = None, e = -1, vl = None):
+ """Create a packing structure for a message."""
base_types = { 'u8' : 'B',
'u16' : 'H',
'u32' : 'I',
raise ValueError(1, 'Invalid message type: ' + t)
def __struct_type(self, encode, msgdef, buf, offset, kwargs):
+ """Get a message packer or unpacker."""
if encode:
return self.__struct_type_encode(msgdef, buf, offset, kwargs)
else:
def make_function(self, name, i, msgdef, multipart, async):
if (async):
- f = lambda **kwargs: (self._call_vpp_async(i, msgdef, multipart, **kwargs))
+ f = lambda **kwargs: (self._call_vpp_async(i, msgdef, **kwargs))
else:
f = lambda **kwargs: (self._call_vpp(i, msgdef, multipart, **kwargs))
args = self.messages[name]['args']
f.__doc__ = ", ".join(["%s %s" % (argtypes[k], k) for k in args.keys()])
return f
+ @property
+ def api(self):
+ if not hasattr(self, "_api"):
+ raise Exception("Not connected, api definitions not available")
+ return self._api
+
def _register_functions(self, async=False):
self.id_names = [None] * (self.vpp_dictionary_maxid + 1)
self.id_msgdef = [None] * (self.vpp_dictionary_maxid + 1)
+ self._api = Empty()
for name, msgdef in self.messages.iteritems():
if name in self.vpp_dictionary:
if self.messages[name]['crc'] != self.vpp_dictionary[name]['crc']:
self.id_msgdef[i] = msgdef
self.id_names[i] = name
multipart = True if name.find('_dump') > 0 else False
- setattr(self, name, self.make_function(name, i, msgdef, multipart, async))
+ f = self.make_function(name, i, msgdef, multipart, async)
+ setattr(self._api, name, FuncWrapper(f))
+
+ # old API stuff starts here - will be removed in 17.07
+ if hasattr(self, name):
+ raise NameError(
+ 3, "Conflicting name in JSON definition: `%s'" % name)
+ setattr(self, name, f)
+ # old API stuff ends here
def _write (self, buf):
+ """Send a binary-packed message to VPP."""
if not self.connected:
raise IOError(1, 'Not connected')
return vpp_api.write(str(buf))
+ def _read (self):
+ if not self.connected:
+ raise IOError(1, 'Not connected')
+
+ return vpp_api.read(self.read_timeout)
+
def _load_dictionary(self):
self.vpp_dictionary = {}
self.vpp_dictionary_maxid = 0
self.vpp_dictionary[name] = { 'id' : i, 'crc' : crc }
self.vpp_dictionary_maxid = max(self.vpp_dictionary_maxid, i)
- def connect(self, name, chroot_prefix = None, async = False):
- msg_handler = self.msg_handler if not async else self.msg_handler_async
- if not chroot_prefix:
- rv = vpp_api.connect(name, msg_handler)
- else:
- rv = vpp_api.connect(name, msg_handler, chroot_prefix)
-
+ def connect_internal(self, name, msg_handler, chroot_prefix, rx_qlen, async):
+ rv = vpp_api.connect(name, msg_handler, chroot_prefix, rx_qlen)
if rv != 0:
raise IOError(2, 'Connect failed')
self.connected = True
self.control_ping_index = self.vpp_dictionary['control_ping']['id']
self.control_ping_msgdef = self.messages['control_ping']
- def disconnect(self):
- rv = vpp_api.disconnect()
- return rv
-
- def results_wait(self, context):
- return (self.results[context]['e'].wait(self.timeout))
+ def connect(self, name, chroot_prefix = None, async = False, rx_qlen = 32):
+ """Attach to VPP.
- def results_prepare(self, context):
- self.results[context] = {}
- self.results[context]['e'] = threading.Event()
- self.results[context]['e'].clear()
- self.results[context]['r'] = []
+ name - the name of the client.
+ chroot_prefix - if VPP is chroot'ed, the prefix of the jail
+ async - if true, messages are sent without waiting for a reply
+ rx_qlen - the length of the VPP message receive queue between
+ client and server.
+ """
+ msg_handler = self.msg_handler_sync if not async \
+ else self.msg_handler_async
+ return self.connect_internal(name, msg_handler, chroot_prefix, rx_qlen,
+ async)
- def results_clean(self, context):
- del self.results[context]
+ def connect_sync (self, name, chroot_prefix = None, rx_qlen = 32):
+ """Attach to VPP in synchronous mode. Application must poll for events.
- def msg_handler(self, msg):
- if not msg:
- eprint('vpp_api.read failed')
- return
-
- i, ci = self.header.unpack_from(msg, 0)
- if self.id_names[i] == 'rx_thread_exit':
- return;
+ name - the name of the client.
+ chroot_prefix - if VPP is chroot'ed, the prefix of the jail
+ rx_qlen - the length of the VPP message receive queue between
+ client and server.
+ """
- #
- # Decode message and returns a tuple.
- #
- msgdef = self.id_msgdef[i]
- if not msgdef:
- raise IOError(2, 'Reply message undefined')
-
- r = self.decode(msgdef, msg)
- if 'context' in r._asdict():
- if r.context > 0:
- context = r.context
+ return self.connect_internal(name, None, chroot_prefix, rx_qlen,
+ async=False)
- msgname = type(r).__name__
+ def disconnect(self):
+ """Detach from VPP."""
+ rv = vpp_api.disconnect()
+ self.connected = False
+ return rv
- #
- # XXX: Call provided callback for event
- # Are we guaranteed to not get an event during processing of other messages?
- # How to differentiate what's a callback message and what not? Context = 0?
- #
- #if not is_waiting_for_reply():
- if r.context == 0 and self.event_callback:
- self.event_callback(msgname, r)
- return
+ def msg_handler_sync(self, msg):
+ """Process an incoming message from VPP in sync mode.
- #
- # Collect results until control ping
- #
- if msgname == 'control_ping_reply':
- self.results[context]['e'].set()
+ The message may be a reply or it may be an async notification.
+ """
+ r = self.decode_incoming_msg(msg)
+ if r is None:
return
- if not context in self.results:
- eprint('Not expecting results for this context', context, r)
- return
+ # If we have a context, then use the context to find any
+ # request waiting for a reply
+ context = 0
+ if hasattr(r, 'context') and r.context > 0:
+ context = r.context
- if 'm' in self.results[context]:
- self.results[context]['r'].append(r)
- return
+ msgname = type(r).__name__
- self.results[context]['r'] = r
- self.results[context]['e'].set()
+ if context == 0:
+ # No context -> async notification that we feed to the callback
+ self.message_queue.put_nowait(r)
+ else:
+ raise IOError(2, 'RPC reply message received in event handler')
- def msg_handler_async(self, msg):
+ def decode_incoming_msg(self, msg):
if not msg:
eprint('vpp_api.read failed')
return
i, ci = self.header.unpack_from(msg, 0)
if self.id_names[i] == 'rx_thread_exit':
- return;
+ return
#
# Decode message and returns a tuple.
raise IOError(2, 'Reply message undefined')
r = self.decode(msgdef, msg)
+
+ return r
+
+ def msg_handler_async(self, msg):
+ """Process a message from VPP in async mode.
+
+ In async mode, all messages are returned to the callback.
+ """
+ r = self.decode_incoming_msg(msg)
+ if r is None:
+ return
+
msgname = type(r).__name__
- self.event_callback(msgname, r)
+ if self.event_callback:
+ self.event_callback(msgname, r)
def _control_ping(self, context):
- self._write(self.encode(self.control_ping_msgdef,
- { '_vl_msg_id' : self.control_ping_index,
- 'context' : context}))
+ """Send a ping command."""
+ self._call_vpp_async(self.control_ping_index,
+ self.control_ping_msgdef,
+ context=context)
def _call_vpp(self, i, msgdef, multipart, **kwargs):
+ """Given a message, send the message and await a reply.
+
+ msgdef - the message packing definition
+ i - the message type index
+ multipart - True if the message returns multiple
+ messages in return.
+ context - context number - chosen at random if not
+ supplied.
+ The remainder of the kwargs are the arguments to the API call.
+
+ The return value is the message or message array containing
+ the response. It will raise an IOError exception if there was
+ no response within the timeout window.
+ """
+
if not 'context' in kwargs:
context = self.get_context()
kwargs['context'] = context
kwargs['_vl_msg_id'] = i
b = self.encode(msgdef, kwargs)
- self.results_prepare(context)
+ vpp_api.suspend()
self._write(b)
if multipart:
- self.results[context]['m'] = True
+ # Send a ping after the request - we use its response
+ # to detect that we have seen all results.
self._control_ping(context)
- self.results_wait(context)
- r = self.results[context]['r']
- self.results_clean(context)
- return r
- def _call_vpp_async(self, i, msgdef, multipart, **kwargs):
+ # Block until we get a reply.
+ rl = []
+ while (True):
+ msg = self._read()
+ if not msg:
+ print('PNEUM ERROR: OH MY GOD')
+ raise IOError(2, 'PNEUM read failed')
+
+ r = self.decode_incoming_msg(msg)
+ msgname = type(r).__name__
+ if not context in r or r.context == 0 or context != r.context:
+ self.message_queue.put_nowait(r)
+ continue
+
+ if not multipart:
+ rl = r
+ break
+ if msgname == 'control_ping_reply':
+ break
+
+ rl.append(r)
+
+ vpp_api.resume()
+
+ return rl
+
+ def _call_vpp_async(self, i, msgdef, **kwargs):
+ """Given a message, send the message and await a reply.
+
+ msgdef - the message packing definition
+ i - the message type index
+ context - context number - chosen at random if not
+ supplied.
+ The remainder of the kwargs are the arguments to the API call.
+ """
if not 'context' in kwargs:
context = self.get_context()
kwargs['context'] = context
self._write(b)
def register_event_callback(self, callback):
+ """Register a callback for async messages.
+
+ This will be called for async notifications in sync mode,
+ and all messages in async mode. In sync mode, replies to
+ requests will not come here.
+
+ callback is a fn(msg_type_name, msg_type) that will be
+ called when a message comes in. While this function is
+ executing, note that (a) you are in a background thread and
+ may wish to use threading.Lock to protect your datastructures,
+ and (b) message processing from VPP will stop (so if you take
+ a long while about it you may provoke reply timeouts or cause
+ VPP to fill the RX buffer). Passing None will disable the
+ callback.
+ """
self.event_callback = callback
+ def thread_msg_handler(self):
+ """Python thread calling the user registerd message handler.
+
+ This is to emulate the old style event callback scheme. Modern
+ clients should provide their own thread to poll the event
+ queue.
+ """
+ while True:
+ r = self.message_queue.get()
+ msgname = type(r).__name__
+ if self.event_callback:
+ self.event_callback(msgname, r)
Code Review / vpp.git / blobdiff