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authorOle Troan <ot@cisco.com>2017-03-08 12:02:24 +0100
committerOle Troan <ot@cisco.com>2017-03-15 21:43:30 +0100
commit3cc4971882235a539bc6177e8e4b4d92129b3a12 (patch)
treec850b1ea3348da7cd632e782008fbe4e3c6b4c87 /src/vpp-api/python/vpp_papi.py
parent9d676afbb779da5186cb3869925ef6d7d3d04db1 (diff)
Python API: Change from cPython to CFFI.
Change-Id: I03e52466fb3f909ae52b8fba601168f3eadbd972 Signed-off-by: Ole Troan <ot@cisco.com>
Diffstat (limited to 'src/vpp-api/python/vpp_papi.py')
-rw-r--r--src/vpp-api/python/vpp_papi.py635
1 files changed, 635 insertions, 0 deletions
diff --git a/src/vpp-api/python/vpp_papi.py b/src/vpp-api/python/vpp_papi.py
new file mode 100644
index 00000000000..81f6903be5a
--- /dev/null
+++ b/src/vpp-api/python/vpp_papi.py
@@ -0,0 +1,635 @@
+#!/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, Queue
+
+from cffi import FFI
+ffi = FFI()
+ffi.cdef("""
+typedef void (*pneum_callback_t)(unsigned char * data, int len);
+typedef void (*pneum_error_callback_t)(void *, unsigned char *, int);
+int pneum_connect(char * name, char * chroot_prefix, pneum_callback_t cb,
+ int rx_qlen);
+int pneum_disconnect(void);
+int pneum_read(char **data, int *l, unsigned short timeout);
+int pneum_write(char *data, int len);
+void pneum_free(void * msg);
+
+int pneum_get_msg_index(unsigned char * name);
+int pneum_msg_table_size(void);
+int pneum_msg_table_max_index(void);
+
+void pneum_rx_suspend (void);
+void pneum_rx_resume (void);
+void pneum_set_error_handler(pneum_error_callback_t);
+ """)
+
+# Barfs on failure, no need to check success.
+vpp_api = ffi.dlopen('libpneum.so')
+
+def vpp_atexit(self):
+ """Clean up VPP connection on shutdown."""
+ if self.connected:
+ self.logger.debug('Cleaning up VPP on exit')
+ self.disconnect()
+
+vpp_object = None
+
+@ffi.callback("void(unsigned char *, int)")
+def pneum_callback_sync(data, len):
+ vpp_object.msg_handler_sync(ffi.buffer(data, len))
+@ffi.callback("void(unsigned char *, int)")
+def pneum_callback_async(data, len):
+ vpp_object.msg_handler_async(ffi.buffer(data, len))
+@ffi.callback("void(void *, unsigned char *, int)")
+def pneum_error_handler(arg, msg, msg_len):
+ vpp_object.logger.warning("PNEUM: %s", ffi.string(msg, msg_len))
+
+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():
+ """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,
+ logger = logging.getLogger('vpp_papi'), loglevel = 'debug'):
+ """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.
+ """
+ global vpp_object
+ vpp_object = self
+ self.logger = logger
+ logging.basicConfig(level=getattr(logging, loglevel.upper()))
+
+ self.messages = {}
+ self.id_names = []
+ self.id_msgdef = []
+ self.buffersize = 10000
+ self.connected = False
+ self.header = struct.Struct('>HI')
+ 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:
+ 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)
+
+ # Register error handler
+ vpp_api.pneum_set_error_handler(pneum_error_handler)
+
+ 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, typeonly = False):
+ 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
+ self.messages[name]['typeonly'] = typeonly
+ return self.messages[name]
+
+ def add_type(self, name, typedef):
+ return self.add_message('vl_api_' + name + '_t', typedef, typeonly=True)
+
+ 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
+
+ @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 self.messages[name]['typeonly']: continue
+ crc = self.messages[name]['crc']
+ n = name + '_' + crc[2:]
+ i = vpp_api.pneum_get_msg_index(bytes(n))
+ if i > 0:
+ self.id_msgdef[i] = msgdef
+ self.id_names[i] = name
+ multipart = True if name.find('_dump') > 0 else False
+ 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
+ else:
+ self.logger.debug('No such message type or failed CRC checksum: %s', n)
+
+ def _write (self, buf):
+ """Send a binary-packed message to VPP."""
+ if not self.connected:
+ raise IOError(1, 'Not connected')
+ return vpp_api.pneum_write(str(buf), len(buf))
+
+ def _read (self):
+ if not self.connected:
+ raise IOError(1, 'Not connected')
+ mem = ffi.new("char **")
+ size = ffi.new("int *")
+ rv = vpp_api.pneum_read(mem, size, self.read_timeout)
+ if rv:
+ raise IOError(rv, 'pneum_read filed')
+ msg = bytes(ffi.buffer(mem[0], size[0]))
+ vpp_api.pneum_free(mem[0])
+ return msg
+
+ def connect_internal(self, name, msg_handler, chroot_prefix, rx_qlen, async):
+ rv = vpp_api.pneum_connect(name, chroot_prefix, msg_handler, rx_qlen)
+ if rv != 0:
+ raise IOError(2, 'Connect failed')
+ self.connected = True
+
+ self.vpp_dictionary_maxid = vpp_api.pneum_msg_table_max_index()
+ self._register_functions(async=async)
+
+ # Initialise control ping
+ crc = self.messages['control_ping']['crc']
+ self.control_ping_index = \
+ vpp_api.pneum_get_msg_index(
+ bytes('control_ping' + '_' + crc[2:]))
+ self.control_ping_msgdef = self.messages['control_ping']
+
+ def connect(self, name, chroot_prefix = ffi.NULL,
+ async = False, rx_qlen = 32):
+ """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 = pneum_callback_sync if not async \
+ else pneum_callback_async
+ return self.connect_internal(name, msg_handler, chroot_prefix, rx_qlen,
+ async)
+
+ def connect_sync (self, name, chroot_prefix = ffi.NULL, rx_qlen = 32):
+ """Attach to VPP in synchronous mode. Application must poll for events.
+
+ 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.
+ """
+
+ return self.connect_internal(name, ffi.NULL, chroot_prefix, rx_qlen,
+ async=False)
+
+ def disconnect(self):
+ """Detach from VPP."""
+ rv = vpp_api.pneum_disconnect()
+ self.connected = False
+ return rv
+
+ 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
+ self.message_queue.put_nowait(r)
+ else:
+ raise IOError(2, 'RPC reply message received in event handler')
+
+ def decode_incoming_msg(self, msg):
+ if not msg:
+ self.logger.warning('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.
+ """
+
+ 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)
+
+ vpp_api.pneum_rx_suspend()
+ self._write(b)
+
+ 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.
+ 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.pneum_rx_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
+ 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
+
+ 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)