papi: fix async support for socket transport
[vpp.git] / src / vpp-api / python / vpp_papi / vpp_papi.py
index 8de1e4b..6755e22 100644 (file)
@@ -1,4 +1,4 @@
-#!/usr/bin/env python
+#!/usr/bin/env python3
 #
 # Copyright (c) 2016 Cisco and/or its affiliates.
 # Licensed under the Apache License, Version 2.0 (the "License");
 #
 # Copyright (c) 2016 Cisco and/or its affiliates.
 # Licensed under the Apache License, Version 2.0 (the "License");
 #
 
 from __future__ import print_function
 #
 
 from __future__ import print_function
-import sys, os, logging, collections, struct, json, threading, glob
+from __future__ import absolute_import
+import ctypes
+import ipaddress
+import sys
+import multiprocessing as mp
+import os
+import queue
+import logging
+import functools
+import json
+import threading
+import fnmatch
+import weakref
 import atexit
 import atexit
+import time
+from .vpp_format import verify_enum_hint
+from .vpp_serializer import VPPType, VPPEnumType, VPPEnumFlagType, VPPUnionType
+from .vpp_serializer import VPPMessage, vpp_get_type, VPPTypeAlias
+
+try:
+    import VppTransport
+except ModuleNotFoundError:
+
+    class V:
+        """placeholder for VppTransport as the implementation is dependent on
+        VPPAPIClient's initialization values
+        """
+
+    VppTransport = V
+
+from .vpp_transport_socket import VppTransport
+
+logger = logging.getLogger("vpp_papi")
+logger.addHandler(logging.NullHandler())
+
+__all__ = (
+    "FuncWrapper",
+    "VppApiDynamicMethodHolder",
+    "VppEnum",
+    "VppEnumType",
+    "VppEnumFlag",
+    "VPPIOError",
+    "VPPRuntimeError",
+    "VPPValueError",
+    "VPPApiClient",
+)
+
+
+def metaclass(metaclass):
+    @functools.wraps(metaclass)
+    def wrapper(cls):
+        return metaclass(cls.__name__, cls.__bases__, cls.__dict__.copy())
+
+    return wrapper
+
 
 
-logging.basicConfig(level=logging.DEBUG)
-import vpp_api
+class VppEnumType(type):
+    def __getattr__(cls, name):
+        t = vpp_get_type(name)
+        return t.enum
 
 
-def eprint(*args, **kwargs):
-    """Print critical diagnostics to stderr."""
-    print(*args, file=sys.stderr, **kwargs)
 
 
-def vpp_atexit(self):
+@metaclass(VppEnumType)
+class VppEnum:
+    pass
+
+
+@metaclass(VppEnumType)
+class VppEnumFlag:
+    pass
+
+
+def vpp_atexit(vpp_weakref):
     """Clean up VPP connection on shutdown."""
     """Clean up VPP connection on shutdown."""
-    if self.connected:
-        eprint ('Cleaning up VPP on exit')
-        self.disconnect()
+    vpp_instance = vpp_weakref()
+    if vpp_instance and vpp_instance.transport.connected:
+        logger.debug("Cleaning up VPP on exit")
+        vpp_instance.disconnect()
+
+
+def add_convenience_methods():
+    # provide convenience methods to IP[46]Address.vapi_af
+    def _vapi_af(self):
+        if 6 == self._version:
+            return VppEnum.vl_api_address_family_t.ADDRESS_IP6.value
+        if 4 == self._version:
+            return VppEnum.vl_api_address_family_t.ADDRESS_IP4.value
+        raise ValueError("Invalid _version.")
+
+    def _vapi_af_name(self):
+        if 6 == self._version:
+            return "ip6"
+        if 4 == self._version:
+            return "ip4"
+        raise ValueError("Invalid _version.")
+
+    ipaddress._IPAddressBase.vapi_af = property(_vapi_af)
+    ipaddress._IPAddressBase.vapi_af_name = property(_vapi_af_name)
+
+
+class VppApiDynamicMethodHolder:
+    pass
+
+
+class FuncWrapper:
+    def __init__(self, func):
+        self._func = func
+        self.__name__ = func.__name__
+        self.__doc__ = func.__doc__
+
+    def __call__(self, **kwargs):
+        return self._func(**kwargs)
+
+    def __repr__(self):
+        return "<FuncWrapper(func=<%s(%s)>)>" % (self.__name__, self.__doc__)
+
+
+class VPPApiError(Exception):
+    pass
+
+
+class VPPNotImplementedError(NotImplementedError):
+    pass
+
+
+class VPPIOError(IOError):
+    pass
+
+
+class VPPRuntimeError(RuntimeError):
+    pass
+
+
+class VPPValueError(ValueError):
+    pass
+
+
+class VPPApiJSONFiles:
+    @classmethod
+    def find_api_dir(cls, dirs):
+        """Attempt to find the best directory in which API definition
+        files may reside. If the value VPP_API_DIR exists in the environment
+        then it is first on the search list. If we're inside a recognized
+        location in a VPP source tree (src/scripts and src/vpp-api/python)
+        then entries from there to the likely locations in build-root are
+        added. Finally the location used by system packages is added.
 
 
-class VPP():
+        :returns: A single directory name, or None if no such directory
+            could be found.
+        """
+
+        # perhaps we're in the 'src/scripts' or 'src/vpp-api/python' dir;
+        # in which case, plot a course to likely places in the src tree
+        import __main__ as main
+
+        if hasattr(main, "__file__"):
+            # get the path of the calling script
+            localdir = os.path.dirname(os.path.realpath(main.__file__))
+        else:
+            # use cwd if there is no calling script
+            localdir = os.getcwd()
+        localdir_s = localdir.split(os.path.sep)
+
+        def dmatch(dir):
+            """Match dir against right-hand components of the script dir"""
+            d = dir.split("/")  # param 'dir' assumes a / separator
+            length = len(d)
+            return len(localdir_s) > length and localdir_s[-length:] == d
+
+        def sdir(srcdir, variant):
+            """Build a path from srcdir to the staged API files of
+            'variant'  (typically '' or '_debug')"""
+            # Since 'core' and 'plugin' files are staged
+            # in separate directories, we target the parent dir.
+            return os.path.sep.join(
+                (
+                    srcdir,
+                    "build-root",
+                    "install-vpp%s-native" % variant,
+                    "vpp",
+                    "share",
+                    "vpp",
+                    "api",
+                )
+            )
+
+        srcdir = None
+        if dmatch("src/scripts"):
+            srcdir = os.path.sep.join(localdir_s[:-2])
+        elif dmatch("src/vpp-api/python"):
+            srcdir = os.path.sep.join(localdir_s[:-3])
+        elif dmatch("test"):
+            # we're apparently running tests
+            srcdir = os.path.sep.join(localdir_s[:-1])
+
+        if srcdir:
+            # we're in the source tree, try both the debug and release
+            # variants.
+            dirs.append(sdir(srcdir, "_debug"))
+            dirs.append(sdir(srcdir, ""))
+
+        # Test for staged copies of the scripts
+        # For these, since we explicitly know if we're running a debug versus
+        # release variant, target only the relevant directory
+        if dmatch("build-root/install-vpp_debug-native/vpp/bin"):
+            srcdir = os.path.sep.join(localdir_s[:-4])
+            dirs.append(sdir(srcdir, "_debug"))
+        if dmatch("build-root/install-vpp-native/vpp/bin"):
+            srcdir = os.path.sep.join(localdir_s[:-4])
+            dirs.append(sdir(srcdir, ""))
+
+        # finally, try the location system packages typically install into
+        dirs.append(os.path.sep.join(("", "usr", "share", "vpp", "api")))
+
+        # check the directories for existence; first one wins
+        for dir in dirs:
+            if os.path.isdir(dir):
+                return dir
+
+        return None
+
+    @classmethod
+    def find_api_files(cls, api_dir=None, patterns="*"):  # -> list
+        """Find API definition files from the given directory tree with the
+        given pattern. If no directory is given then find_api_dir() is used
+        to locate one. If no pattern is given then all definition files found
+        in the directory tree are used.
+
+        :param api_dir: A directory tree in which to locate API definition
+            files; subdirectories are descended into.
+            If this is None then find_api_dir() is called to discover it.
+        :param patterns: A list of patterns to use in each visited directory
+            when looking for files.
+            This can be a list/tuple object or a comma-separated string of
+            patterns. Each value in the list will have leading/trialing
+            whitespace stripped.
+            The pattern specifies the first part of the filename, '.api.json'
+            is appended.
+            The results are de-duplicated, thus overlapping patterns are fine.
+            If this is None it defaults to '*' meaning "all API files".
+        :returns: A list of file paths for the API files found.
+        """
+        if api_dir is None:
+            api_dir = cls.find_api_dir([])
+            if api_dir is None:
+                raise VPPApiError("api_dir cannot be located")
+
+        if isinstance(patterns, list) or isinstance(patterns, tuple):
+            patterns = [p.strip() + ".api.json" for p in patterns]
+        else:
+            patterns = [p.strip() + ".api.json" for p in patterns.split(",")]
+
+        api_files = []
+        for root, dirnames, files in os.walk(api_dir):
+            # iterate all given patterns and de-dup the result
+            files = set(sum([fnmatch.filter(files, p) for p in patterns], []))
+            for filename in files:
+                api_files.append(os.path.join(root, filename))
+
+        return api_files
+
+    @classmethod
+    def process_json_file(self, apidef_file):
+        api = json.load(apidef_file)
+        return self._process_json(api)
+
+    @classmethod
+    def process_json_str(self, json_str):
+        api = json.loads(json_str)
+        return self._process_json(api)
+
+    @staticmethod
+    def _process_json(api):  # -> Tuple[Dict, Dict]
+        types = {}
+        services = {}
+        messages = {}
+        try:
+            for t in api["enums"]:
+                t[0] = "vl_api_" + t[0] + "_t"
+                types[t[0]] = {"type": "enum", "data": t}
+        except KeyError:
+            pass
+        try:
+            for t in api["enumflags"]:
+                t[0] = "vl_api_" + t[0] + "_t"
+                types[t[0]] = {"type": "enum", "data": t}
+        except KeyError:
+            pass
+        try:
+            for t in api["unions"]:
+                t[0] = "vl_api_" + t[0] + "_t"
+                types[t[0]] = {"type": "union", "data": t}
+        except KeyError:
+            pass
+
+        try:
+            for t in api["types"]:
+                t[0] = "vl_api_" + t[0] + "_t"
+                types[t[0]] = {"type": "type", "data": t}
+        except KeyError:
+            pass
+
+        try:
+            for t, v in api["aliases"].items():
+                types["vl_api_" + t + "_t"] = {"type": "alias", "data": v}
+        except KeyError:
+            pass
+
+        try:
+            services.update(api["services"])
+        except KeyError:
+            pass
+
+        i = 0
+        while True:
+            unresolved = {}
+            for k, v in types.items():
+                t = v["data"]
+                if not vpp_get_type(k):
+                    if v["type"] == "enum":
+                        try:
+                            VPPEnumType(t[0], t[1:])
+                        except ValueError:
+                            unresolved[k] = v
+                if not vpp_get_type(k):
+                    if v["type"] == "enumflag":
+                        try:
+                            VPPEnumFlagType(t[0], t[1:])
+                        except ValueError:
+                            unresolved[k] = v
+                    elif v["type"] == "union":
+                        try:
+                            VPPUnionType(t[0], t[1:])
+                        except ValueError:
+                            unresolved[k] = v
+                    elif v["type"] == "type":
+                        try:
+                            VPPType(t[0], t[1:])
+                        except ValueError:
+                            unresolved[k] = v
+                    elif v["type"] == "alias":
+                        try:
+                            VPPTypeAlias(k, t)
+                        except ValueError:
+                            unresolved[k] = v
+            if len(unresolved) == 0:
+                break
+            if i > 3:
+                raise VPPValueError("Unresolved type definitions {}".format(unresolved))
+            types = unresolved
+            i += 1
+        try:
+            for m in api["messages"]:
+                try:
+                    messages[m[0]] = VPPMessage(m[0], m[1:])
+                except VPPNotImplementedError:
+                    ### OLE FIXME
+                    logger.error("Not implemented error for {}".format(m[0]))
+        except KeyError:
+            pass
+        return messages, services
+
+
+class VPPApiClient:
     """VPP interface.
 
     This class provides the APIs to VPP.  The APIs are loaded
     """VPP interface.
 
     This class provides the APIs to VPP.  The APIs are loaded
@@ -43,7 +390,26 @@ class VPP():
     provides a means to register a callback function to receive
     these messages in a background thread.
     """
     provides a means to register a callback function to receive
     these messages in a background thread.
     """
-    def __init__(self, apifiles = None, testmode = False):
+
+    apidir = None
+    VPPApiError = VPPApiError
+    VPPRuntimeError = VPPRuntimeError
+    VPPValueError = VPPValueError
+    VPPNotImplementedError = VPPNotImplementedError
+    VPPIOError = VPPIOError
+
+    def __init__(
+        self,
+        *,
+        apifiles=None,
+        testmode=False,
+        async_thread=True,
+        logger=None,
+        loglevel=None,
+        read_timeout=5,
+        use_socket=True,
+        server_address="/run/vpp/api.sock",
+    ):
         """Create a VPP API object.
 
         apifiles is a list of files containing API
         """Create a VPP API object.
 
         apifiles is a list of files containing API
@@ -51,379 +417,187 @@ class VPP():
         dynamically created reflecting these APIs.  If not
         provided this will load the API files from VPP's
         default install location.
         dynamically created reflecting these APIs.  If not
         provided this will load the API files from VPP's
         default install location.
+
+        logger, if supplied, is the logging logger object to log to.
+        loglevel, if supplied, is the log level this logger is set
+        to report at (from the loglevels in the logging module).
         """
         """
+        if logger is None:
+            logger = logging.getLogger(
+                "{}.{}".format(__name__, self.__class__.__name__)
+            )
+            if loglevel is not None:
+                logger.setLevel(loglevel)
+        self.logger = logger
+
         self.messages = {}
         self.messages = {}
+        self.services = {}
         self.id_names = []
         self.id_msgdef = []
         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.header = VPPType("header", [["u16", "msgid"], ["u32", "client_index"]])
         self.apifiles = []
         self.apifiles = []
+        self.event_callback = None
+        self.message_queue = queue.Queue()
+        self.read_timeout = read_timeout
+        self.async_thread = async_thread
+        self.event_thread = None
+        self.testmode = testmode
+        self.server_address = server_address
+        self._apifiles = apifiles
+        self.stats = {}
 
         if not apifiles:
             # Pick up API definitions from default directory
 
         if not apifiles:
             # Pick up API definitions from default directory
-            apifiles = glob.glob('/usr/share/vpp/api/*.api.json')
+            try:
+                apifiles = VPPApiJSONFiles.find_api_files(self.apidir)
+            except (RuntimeError, VPPApiError):
+                # In test mode we don't care that we can't find the API files
+                if testmode:
+                    apifiles = []
+                else:
+                    raise VPPRuntimeError
 
         for file in apifiles:
             with open(file) as apidef_file:
 
         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:])
+                m, s = VPPApiJSONFiles.process_json_file(apidef_file)
+                self.messages.update(m)
+                self.services.update(s)
 
 
-                for m in api['messages']:
-                    self.add_message(m[0], m[1:])
-       self.apifiles = apifiles
+        self.apifiles = apifiles
 
         # Basic sanity check
         if len(self.messages) == 0 and not testmode:
 
         # Basic sanity check
         if len(self.messages) == 0 and not testmode:
-            raise ValueError(1, 'Missing JSON message definitions')
+            raise VPPValueError(1, "Missing JSON message definitions")
+        if not (verify_enum_hint(VppEnum.vl_api_address_family_t)):
+            raise VPPRuntimeError("Invalid address family hints. " "Cannot continue.")
 
 
+        self.transport = VppTransport(
+            self, read_timeout=read_timeout, server_address=server_address
+        )
         # Make sure we allow VPP to clean up the message rings.
         # Make sure we allow VPP to clean up the message rings.
-        atexit.register(vpp_atexit, self)
+        atexit.register(vpp_atexit, weakref.ref(self))
+
+        add_convenience_methods()
+
+    def get_function(self, name):
+        return getattr(self._api, name)
+
+    class ContextId:
+        """Multiprocessing-safe provider of unique context IDs."""
 
 
-    class ContextId(object):
-        """Thread-safe provider of unique context IDs."""
         def __init__(self):
         def __init__(self):
-            self.context = 0
-           self.lock = threading.Lock()
+            self.context = mp.Value(ctypes.c_uint, 0)
+            self.lock = mp.Lock()
+
         def __call__(self):
             """Get a new unique (or, at least, not recently used) context."""
         def __call__(self):
             """Get a new unique (or, at least, not recently used) context."""
-           with self.lock:
-               self.context += 1
-               return self.context
+            with self.lock:
+                self.context.value += 1
+                return self.context.value
+
     get_context = ContextId()
 
     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)
-            )
+    def get_type(self, name):
+        return vpp_get_type(name)
+
+    @property
+    def api(self):
+        if not hasattr(self, "_api"):
+            raise VPPApiError("Not connected, api definitions not available")
+        return self._api
+
+    def make_function(self, msg, i, multipart, do_async):
+        if do_async:
 
 
-        raise ValueError(1, 'Invalid message type: ' + t)
+            def f(**kwargs):
+                return self._call_vpp_async(i, msg, **kwargs)
 
 
-    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:
         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 f(**kwargs):
+                return self._call_vpp(i, msg, multipart, **kwargs)
 
 
+        f.__name__ = str(msg.name)
+        f.__doc__ = ", ".join(
+            ["%s %s" % (msg.fieldtypes[j], k) for j, k in enumerate(msg.fields)]
+        )
+        f.msg = msg
 
 
-    def __getitem__(self, name):
-        if name in self.messages:
-            return self.messages[name]
-        return None
+        return f
 
 
-    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
+    def _register_functions(self, do_async=False):
+        self.id_names = [None] * (self.vpp_dictionary_maxid + 1)
+        self.id_msgdef = [None] * (self.vpp_dictionary_maxid + 1)
+        self._api = VppApiDynamicMethodHolder()
+        for name, msg in self.messages.items():
+            n = name + "_" + msg.crc[2:]
+            i = self.transport.get_msg_index(n)
+            if i > 0:
+                self.id_msgdef[i] = msg
+                self.id_names[i] = name
+
+                # Create function for client side messages.
+                if name in self.services:
+                    f = self.make_function(msg, i, self.services[name], do_async)
+                    setattr(self._api, name, FuncWrapper(f))
             else:
             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
+                self.logger.debug("No such message type or failed CRC checksum: %s", n)
 
 
-        return off + size - offset, msgdef['return_tuple']._make(res)
+    def connect_internal(self, name, msg_handler, chroot_prefix, rx_qlen, do_async):
+        pfx = chroot_prefix.encode("utf-8") if chroot_prefix else None
 
 
-    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
+        rv = self.transport.connect(name, pfx, msg_handler, rx_qlen, do_async)
+        if rv != 0:
+            raise VPPIOError(2, "Connect failed")
+        self.vpp_dictionary_maxid = self.transport.msg_table_max_index()
+        self._register_functions(do_async=do_async)
 
 
-    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))
+        # Initialise control ping
+        crc = self.messages["control_ping"].crc
+        self.control_ping_index = self.transport.get_msg_index(
+            ("control_ping" + "_" + crc[2:])
+        )
+        self.control_ping_msgdef = self.messages["control_ping"]
+        if self.async_thread:
+            self.event_thread = threading.Thread(target=self.thread_msg_handler)
+            self.event_thread.daemon = True
+            self.event_thread.start()
         else:
         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
+            self.event_thread = None
+        return rv
 
 
-    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, rx_qlen = 32):
+    def connect(self, name, chroot_prefix=None, do_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
         """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
+        do_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.
         """
         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, rx_qlen, chroot_prefix)
-        else:
-           rv = vpp_api.connect(name, msg_handler, rx_qlen)
+        msg_handler = self.transport.get_callback(do_async)
+        return self.connect_internal(
+            name, msg_handler, chroot_prefix, rx_qlen, do_async
+        )
 
 
-        if rv != 0:
-            raise IOError(2, 'Connect failed')
-        self.connected = True
+    def connect_sync(self, name, chroot_prefix=None, rx_qlen=32):
+        """Attach to VPP in synchronous mode. Application must poll for events.
 
 
-        self._load_dictionary()
-        self._register_functions(async=async)
+        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.
+        """
 
 
-        # Initialise control ping
-        self.control_ping_index = self.vpp_dictionary['control_ping']['id']
-        self.control_ping_msgdef = self.messages['control_ping']
+        return self.connect_internal(name, None, chroot_prefix, rx_qlen, do_async=False)
 
     def disconnect(self):
         """Detach from VPP."""
 
     def disconnect(self):
         """Detach from VPP."""
-        rv = vpp_api.disconnect()
-        self.connected = False
+        rv = self.transport.disconnect()
+        if self.event_thread is not None:
+            self.message_queue.put("terminate event thread")
         return rv
 
         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.
 
     def msg_handler_sync(self, msg):
         """Process an incoming message from VPP in sync mode.
 
@@ -436,58 +610,53 @@ class VPP():
         # If we have a context, then use the context to find any
         # request waiting for a reply
         context = 0
         # 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:
+        if hasattr(r, "context") and r.context > 0:
             context = r.context
 
             context = r.context
 
-        msgname = type(r).__name__
-
         if context == 0:
             # No context -> async notification that we feed to the callback
         if context == 0:
             # No context -> async notification that we feed to the callback
-           if self.event_callback:
-               self.event_callback(msgname, r)
+            self.message_queue.put_nowait(r)
         else:
         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):
+            raise VPPIOError(2, "RPC reply message received in event handler")
+
+    def has_context(self, msg):
+        if len(msg) < 10:
+            return False
+
+        header = VPPType(
+            "header_with_context",
+            [["u16", "msgid"], ["u32", "client_index"], ["u32", "context"]],
+        )
+
+        (i, ci, context), size = header.unpack(msg, 0)
+        if self.id_names[i] == "rx_thread_exit":
+            return
+
+        #
+        # Decode message and returns a tuple.
+        #
+        msgobj = self.id_msgdef[i]
+        if "context" in msgobj.field_by_name and context >= 0:
+            return True
+        return False
+
+    def decode_incoming_msg(self, msg, no_type_conversion=False):
         if not msg:
         if not msg:
-            eprint('vpp_api.read failed')
+            logger.warning("vpp_api.read failed")
             return
 
             return
 
-        i, ci = self.header.unpack_from(msg, 0)
-        if self.id_names[i] == 'rx_thread_exit':
+        (i, ci), size = self.header.unpack(msg, 0)
+        if self.id_names[i] == "rx_thread_exit":
             return
 
         #
         # Decode message and returns a tuple.
         #
             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)
+        msgobj = self.id_msgdef[i]
+        if not msgobj:
+            raise VPPIOError(2, "Reply message undefined")
 
 
+        r, size = msgobj.unpack(msg, ntc=no_type_conversion)
         return r
 
     def msg_handler_async(self, msg):
         return r
 
     def msg_handler_async(self, msg):
@@ -501,16 +670,47 @@ class VPP():
 
         msgname = type(r).__name__
 
 
         msgname = type(r).__name__
 
-       if self.event_callback:
-           self.event_callback(msgname, msg)
+        if self.event_callback:
+            self.event_callback(msgname, r)
 
     def _control_ping(self, context):
         """Send a ping command."""
 
     def _control_ping(self, context):
         """Send a ping command."""
-        self._call_vpp_async(self.control_ping_index,
-                            self.control_ping_msgdef,
-                             context=context)
+        self._call_vpp_async(
+            self.control_ping_index, self.control_ping_msgdef, context=context
+        )
+
+    def validate_args(self, msg, kwargs):
+        d = set(kwargs.keys()) - set(msg.field_by_name.keys())
+        if d:
+            raise VPPValueError("Invalid argument {} to {}".format(list(d), msg.name))
+
+    def _add_stat(self, name, ms):
+        if not name in self.stats:
+            self.stats[name] = {"max": ms, "count": 1, "avg": ms}
+        else:
+            if ms > self.stats[name]["max"]:
+                self.stats[name]["max"] = ms
+            self.stats[name]["count"] += 1
+            n = self.stats[name]["count"]
+            self.stats[name]["avg"] = self.stats[name]["avg"] * (n - 1) / n + ms / n
+
+    def get_stats(self):
+        s = "\n=== API PAPI STATISTICS ===\n"
+        s += "{:<30} {:>4} {:>6} {:>6}\n".format("message", "cnt", "avg", "max")
+        for n in sorted(self.stats.items(), key=lambda v: v[1]["avg"], reverse=True):
+            s += "{:<30} {:>4} {:>6.2f} {:>6.2f}\n".format(
+                n[0], n[1]["count"], n[1]["avg"], n[1]["max"]
+            )
+        return s
 
 
-    def _call_vpp(self, i, msgdef, multipart, **kwargs):
+    def get_field_options(self, msg, fld_name):
+        # when there is an option, the msgdef has 3 elements.
+        # ['u32', 'ring_size', {'default': 1024}]
+        for _def in self.messages[msg].msgdef:
+            if isinstance(_def, list) and len(_def) == 3 and _def[1] == fld_name:
+                return _def[2]
+
+    def _call_vpp(self, i, msgdef, service, **kwargs):
         """Given a message, send the message and await a reply.
 
         msgdef - the message packing definition
         """Given a message, send the message and await a reply.
 
         msgdef - the message packing definition
@@ -525,46 +725,139 @@ class VPP():
         the response.  It will raise an IOError exception if there was
         no response within the timeout window.
         """
         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)
+        ts = time.time()
+        if "context" not in kwargs:
+            context = self.get_context()
+            kwargs["context"] = context
+        else:
+            context = kwargs["context"]
+        kwargs["_vl_msg_id"] = i
+
+        no_type_conversion = kwargs.pop("_no_type_conversion", False)
+        timeout = kwargs.pop("_timeout", None)
+
+        try:
+            if self.transport.socket_index:
+                kwargs["client_index"] = self.transport.socket_index
+        except AttributeError:
+            pass
+        self.validate_args(msgdef, kwargs)
+
+        s = "Calling {}({})".format(
+            msgdef.name, ",".join(["{!r}:{!r}".format(k, v) for k, v in kwargs.items()])
+        )
+        self.logger.debug(s)
+
+        b = msgdef.pack(kwargs)
+        self.transport.suspend()
+
+        self.transport.write(b)
+
+        msgreply = service["reply"]
+        stream = True if "stream" in service else False
+        if stream:
+            if "stream_msg" in service:
+                # New service['reply'] = _reply and service['stream_message'] = _details
+                stream_message = service["stream_msg"]
+                modern = True
+            else:
+                # Old  service['reply'] = _details
+                stream_message = msgreply
+                msgreply = "control_ping_reply"
+                modern = False
+                # 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.
 
         # 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.
+        rl = []
+        while True:
+            r = self.read_blocking(no_type_conversion, timeout)
+            if r is None:
+                raise VPPIOError(2, "VPP API client: read failed")
+            msgname = type(r).__name__
+            if context not in r or r.context == 0 or context != r.context:
+                # Message being queued
+                self.message_queue.put_nowait(r)
+                continue
+            if msgname != msgreply and (stream and (msgname != stream_message)):
+                print("REPLY MISMATCH", msgreply, msgname, stream_message, stream)
+            if not stream:
+                rl = r
+                break
+            if msgname == msgreply:
+                if modern:  # Return both reply and list
+                    rl = r, rl
+                break
+
+            rl.append(r)
+
+        self.transport.resume()
+
+        s = "Return value: {!r}".format(r)
+        if len(s) > 80:
+            s = s[:80] + "..."
+        self.logger.debug(s)
+        te = time.time()
+        self._add_stat(msgdef.name, (te - ts) * 1000)
+        return rl
+
+    def _call_vpp_async(self, i, msg, **kwargs):
+        """Given a message, send the message and return the context.
 
         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.
 
         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.
+
+        The reply message(s) will be delivered later to the registered callback.
+        The returned context will help with assigning which call
+        the reply belongs to.
         """
         """
-        if not 'context' in kwargs:
+        if "context" not in kwargs:
             context = self.get_context()
             context = self.get_context()
-            kwargs['context'] = context
+            kwargs["context"] = context
         else:
         else:
-            context = kwargs['context']
-        kwargs['_vl_msg_id'] = i
-        b = self.encode(msgdef, kwargs)
+            context = kwargs["context"]
+        try:
+            if self.transport.socket_index:
+                kwargs["client_index"] = self.transport.socket_index
+        except AttributeError:
+            kwargs["client_index"] = 0
+        kwargs["_vl_msg_id"] = i
+        b = msg.pack(kwargs)
+
+        self.transport.write(b)
+        return context
 
 
-        self._write(b)
+    def read_blocking(self, no_type_conversion=False, timeout=None):
+        """Get next received message from transport within timeout, decoded.
+
+        Note that notifications have context zero
+        and are not put into receive queue (at least for socket transport),
+        use async_thread with registered callback for processing them.
+
+        If no message appears in the queue within timeout, return None.
+
+        Optionally, type conversion can be skipped,
+        as some of conversions are into less precise types.
+
+        When r is the return value of this, the caller can get message name as:
+            msgname = type(r).__name__
+        and context number (type long) as:
+            context = r.context
+
+        :param no_type_conversion: If false, type conversions are applied.
+        :type no_type_conversion: bool
+        :returns: Decoded message, or None if no message (within timeout).
+        :rtype: Whatever VPPType.unpack returns, depends on no_type_conversion.
+        :raises VppTransportShmemIOError if timed out.
+        """
+        msg = self.transport.read(timeout=timeout)
+        if not msg:
+            return None
+        return self.decode_incoming_msg(msg, no_type_conversion)
 
     def register_event_callback(self, callback):
         """Register a callback for async messages.
 
     def register_event_callback(self, callback):
         """Register a callback for async messages.
@@ -583,3 +876,72 @@ class VPP():
         callback.
         """
         self.event_callback = callback
         callback.
         """
         self.event_callback = callback
+
+    def thread_msg_handler(self):
+        """Python thread calling the user registered 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()
+            if r == "terminate event thread":
+                break
+            msgname = type(r).__name__
+            if self.event_callback:
+                self.event_callback(msgname, r)
+
+    def validate_message_table(self, namecrctable):
+        """Take a dictionary of name_crc message names
+        and returns an array of missing messages"""
+
+        missing_table = []
+        for name_crc in namecrctable:
+            i = self.transport.get_msg_index(name_crc)
+            if i <= 0:
+                missing_table.append(name_crc)
+        return missing_table
+
+    def dump_message_table(self):
+        """Return VPPs API message table as name_crc dictionary"""
+        return self.transport.message_table
+
+    def dump_message_table_filtered(self, msglist):
+        """Return VPPs API message table as name_crc dictionary,
+        filtered by message name list."""
+
+        replies = [self.services[n]["reply"] for n in msglist]
+        message_table_filtered = {}
+        for name in msglist + replies:
+            for k, v in self.transport.message_table.items():
+                if k.startswith(name):
+                    message_table_filtered[k] = v
+                    break
+        return message_table_filtered
+
+    def __repr__(self):
+        return (
+            "<VPPApiClient apifiles=%s, testmode=%s, async_thread=%s, "
+            "logger=%s, read_timeout=%s, "
+            "server_address='%s'>"
+            % (
+                self._apifiles,
+                self.testmode,
+                self.async_thread,
+                self.logger,
+                self.read_timeout,
+                self.server_address,
+            )
+        )
+
+    def details_iter(self, f, **kwargs):
+        cursor = 0
+        while True:
+            kwargs["cursor"] = cursor
+            rv, details = f(**kwargs)
+            for d in details:
+                yield d
+            if rv.retval == 0 or rv.retval != -165:
+                break
+            cursor = rv.cursor