diff options
Diffstat (limited to 'vpp/vpp-api/python/vpp_papi/vpp_papi.py')
| -rw-r--r-- | vpp/vpp-api/python/vpp_papi/vpp_papi.py | 585 |
1 files changed, 585 insertions, 0 deletions
diff --git a/vpp/vpp-api/python/vpp_papi/vpp_papi.py b/vpp/vpp-api/python/vpp_papi/vpp_papi.py new file mode 100644 index 00000000..0a10bf7a --- /dev/null +++ b/vpp/vpp-api/python/vpp_papi/vpp_papi.py @@ -0,0 +1,585 @@ +#!/usr/bin/env python +# +# Copyright (c) 2016 Cisco and/or its affiliates. +# 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 print_function +import sys, os, logging, collections, struct, json, threading, glob +import atexit + +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 VPP(): + """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): + """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_lock = threading.Lock() + self.results = {} + self.timeout = 5 + self.apifiles = [] + + if not apifiles: + # Pick up API definitions from default directory + apifiles = glob.glob('/usr/share/vpp/api/*.api.json') + + for file in apifiles: + with open(file) as apidef_file: + api = json.load(apidef_file) + for t in api['types']: + self.add_type(t[0], t[1:]) + + 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): + """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', ', '.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', + 'i32' : 'i', + 'u64' : 'Q', + 'f64' : 'd', + } + pack = None + if t in base_types: + pack = base_types[t] + if not vl: + if e > 0 and t == 'u8': + # Fixed byte array + return struct.Struct('>' + str(e) + 's') + if e > 0: + # Fixed array of base type + return [e, struct.Struct('>' + base_types[t])] + elif e == 0: + # Old style variable array + return [-1, struct.Struct('>' + base_types[t])] + else: + # Variable length array + return [vl, struct.Struct('>s')] if t == 'u8' else \ + [vl, struct.Struct('>' + base_types[t])] + + return struct.Struct('>' + base_types[t]) + + if t in self.messages: + ### Return a list in case of array ### + if e > 0 and not vl: + return [e, lambda self, encode, buf, offset, args: ( + self.__struct_type(encode, self.messages[t], buf, offset, + args))] + if vl: + return [vl, lambda self, encode, buf, offset, args: ( + self.__struct_type(encode, self.messages[t], buf, offset, + args))] + elif e == 0: + # Old style VLA + raise NotImplementedError(1, 'No support for compound types ' + t) + return lambda self, encode, buf, offset, args: ( + self.__struct_type(encode, self.messages[t], buf, offset, args) + ) + + 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: + return self.__struct_type_decode(msgdef, buf, offset) + + def __struct_type_encode(self, msgdef, buf, offset, kwargs): + off = offset + size = 0 + + for k in kwargs: + if k not in msgdef['args']: + raise ValueError(1, 'Invalid field-name in message call ' + k) + + for k,v in msgdef['args'].iteritems(): + off += size + if k in kwargs: + if type(v) is list: + if callable(v[1]): + e = kwargs[v[0]] if v[0] in kwargs else v[0] + size = 0 + for i in range(e): + size += v[1](self, True, buf, off + size, + kwargs[k][i]) + else: + if v[0] in kwargs: + l = kwargs[v[0]] + else: + l = len(kwargs[k]) + if v[1].size == 1: + buf[off:off + l] = bytearray(kwargs[k]) + size = l + else: + size = 0 + for i in kwargs[k]: + v[1].pack_into(buf, off + size, i) + size += v[1].size + else: + if callable(v): + size = v(self, True, buf, off, kwargs[k]) + else: + v.pack_into(buf, off, kwargs[k]) + size = v.size + else: + size = v.size if not type(v) is list else 0 + + return off + size - offset + + + def __getitem__(self, name): + if name in self.messages: + return self.messages[name] + return None + + def encode(self, msgdef, kwargs): + # Make suitably large buffer + buf = bytearray(self.buffersize) + offset = 0 + size = self.__struct_type(True, msgdef, buf, offset, kwargs) + return buf[:offset + size] + + def decode(self, msgdef, buf): + return self.__struct_type(False, msgdef, buf, 0, None)[1] + + def __struct_type_decode(self, msgdef, buf, offset): + res = [] + off = offset + size = 0 + for k,v in msgdef['args'].iteritems(): + off += size + if type(v) is list: + lst = [] + if callable(v[1]): # compound type + size = 0 + if v[0] in msgdef['args']: # vla + e = res[v[2]] + else: # fixed array + e = v[0] + res.append(lst) + for i in range(e): + (s,l) = v[1](self, False, buf, off + size, None) + lst.append(l) + size += s + continue + if v[1].size == 1: + if type(v[0]) is int: + size = len(buf) - off + else: + size = res[v[2]] + res.append(buf[off:off + size]) + else: + e = v[0] if type(v[0]) is int else res[v[2]] + if e == -1: + e = (len(buf) - off) / v[1].size + lst = [] + res.append(lst) + size = 0 + for i in range(e): + lst.append(v[1].unpack_from(buf, off + size)[0]) + size += v[1].size + else: + if callable(v): + (s,l) = v(self, False, buf, off, None) + res.append(l) + size += s + else: + res.append(v.unpack_from(buf, off)[0]) + size = v.size + + return off + size - offset, msgdef['return_tuple']._make(res) + + def ret_tup(self, name): + if name in self.messages and 'return_tuple' in self.messages[name]: + return self.messages[name]['return_tuple'] + return None + + def add_message(self, name, msgdef): + if name in self.messages: + raise ValueError('Duplicate message name: ' + name) + + args = collections.OrderedDict() + argtypes = collections.OrderedDict() + fields = [] + msg = {} + for i, f in enumerate(msgdef): + if type(f) is dict and 'crc' in f: + msg['crc'] = f['crc'] + continue + field_type = f[0] + field_name = f[1] + if len(f) == 3 and f[2] == 0 and i != len(msgdef) - 2: + raise ValueError('Variable Length Array must be last: ' + name) + args[field_name] = self.__struct(*f) + argtypes[field_name] = field_type + if len(f) == 4: # Find offset to # elements field + args[field_name].append(args.keys().index(f[3]) - i) + fields.append(field_name) + msg['return_tuple'] = collections.namedtuple(name, fields, + rename = True) + self.messages[name] = msg + self.messages[name]['args'] = args + self.messages[name]['argtypes'] = argtypes + return self.messages[name] + + def add_type(self, name, typedef): + return self.add_message('vl_api_' + name + '_t', typedef) + + def make_function(self, name, i, msgdef, multipart, async): + if (async): + 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'] + argtypes = self.messages[name]['argtypes'] + f.__name__ = str(name) + f.__doc__ = ", ".join(["%s %s" % (argtypes[k], k) for k in args.keys()]) + return f + + def _register_functions(self, async=False): + self.id_names = [None] * (self.vpp_dictionary_maxid + 1) + self.id_msgdef = [None] * (self.vpp_dictionary_maxid + 1) + for name, msgdef in self.messages.iteritems(): + if name in self.vpp_dictionary: + if self.messages[name]['crc'] != self.vpp_dictionary[name]['crc']: + raise ValueError(3, 'Failed CRC checksum ' + name + + ' ' + self.messages[name]['crc'] + + ' ' + self.vpp_dictionary[name]['crc']) + i = self.vpp_dictionary[name]['id'] + 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)) + + 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 _load_dictionary(self): + self.vpp_dictionary = {} + self.vpp_dictionary_maxid = 0 + d = vpp_api.msg_table() + + if not d: + raise IOError(3, 'Cannot get VPP API dictionary') + for i,n in d: + name, crc = n.rsplit('_', 1) + crc = '0x' + crc + 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): + """Attach to VPP. + + 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 + if chroot_prefix is not None: + rv = vpp_api.connect(name, msg_handler, chroot_prefix) + else: + rv = vpp_api.connect(name, msg_handler) + + if rv != 0: + raise IOError(2, 'Connect failed') + self.connected = True + + self._load_dictionary() + self._register_functions(async=async) + + # Initialise control ping + self.control_ping_index = self.vpp_dictionary['control_ping']['id'] + self.control_ping_msgdef = self.messages['control_ping'] + + def disconnect(self): + """Detach from VPP.""" + rv = vpp_api.disconnect() + self.connected = False + return rv + + def results_wait(self, context): + """In a sync call, wait for the reply + + The context ID is used to pair reply to request. + """ + + # Results is filled by the background callback. It will + # raise the event when the context receives a response. + # Given there are two threads we have to be careful with the + # use of results and the structures under it, hence the lock. + with self.results_lock: + result = self.results[context] + ev = result['e'] + + timed_out = not ev.wait(self.timeout) + + if timed_out: + raise IOError(3, 'Waiting for reply timed out') + else: + with self.results_lock: + result = self.results[context] + del self.results[context] + return result['r'] + + def results_prepare(self, context, multi=False): + """Prep for receiving a result in response to a request msg + + context - unique context number sent in request and + returned in reply or replies + multi - true if we expect multiple messages from this + reply. + """ + + # The event is used to indicate that all results are in + new_result = { + 'e': threading.Event(), + } + if multi: + # Make it clear to the BG thread it's going to see several + # messages; messages are stored in a results array + new_result['m'] = True + new_result['r'] = [] + + new_result['e'].clear() + + # Put the prepped result structure into results, at which point + # the bg thread can also access it (hence the thread lock) + with self.results_lock: + self.results[context] = new_result + + def msg_handler_sync(self, msg): + """Process an incoming message from VPP in sync mode. + + 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 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 + + msgname = type(r).__name__ + + if context == 0: + # No context -> async notification that we feed to the callback + if self.event_callback: + self.event_callback(msgname, r) + else: + # Context -> use the results structure (carefully) to find + # who we're responding to and return the message to that + # thread + with self.results_lock: + if context not in self.results: + eprint('Not expecting results for this context', context, r) + else: + result = self.results[context] + + # + # Collect results until control ping + # + + if msgname == 'control_ping_reply': + # End of a multipart + result['e'].set() + elif 'm' in self.results[context]: + # One element in a multipart + result['r'].append(r) + else: + # All of a single result + result['r'] = r + result['e'].set() + + 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 + + # + # 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) + + 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__ + + if self.event_callback: + self.event_callback(msgname, r) + + def _control_ping(self, 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. + """ + + # We need a context if not supplied, in order to get the + # response + context = kwargs.get('context', self.get_context()) + kwargs['context'] = context + + # Set up to receive a response + self.results_prepare(context, multi=multipart) + + # Output the message + self._call_vpp_async(i, msgdef, **kwargs) + + if multipart: + # Send a ping after the request - we use its response + # to detect that we have seen all results. + self._control_ping(context) + + # Block until we get a reply. + r = self.results_wait(context) + + return r + + 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 + else: + context = kwargs['context'] + kwargs['_vl_msg_id'] = i + b = self.encode(msgdef, kwargs) + + 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 |