Python-API: Inital commit of Python bindings for the VPP API.

See: https://wiki.fd.io/view/VPP/Python_API

Change-Id: If135fc32208c7031787e1935b399d930e0e1ea1f
Signed-off-by: Ole Troan <ot@cisco.com>

1 files changed, 337 insertions, 0 deletions

diff --git a/vpp-api/python/pneum/api-gen.py b/vpp-api/python/pneum/api-gen.py
new file mode 100755
index 00000000000..bbc9c3290ac
--- /dev/null
+++ b/vpp-api/python/pneum/api-gen.py
@@ -0,0 +1,337 @@
+#!/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.
+#
+
+import argparse, sys, os, importlib, pprint
+
+parser = argparse.ArgumentParser(description='VPP Python API generator')
+parser.add_argument('-i', action="store", dest="inputfile")
+parser.add_argument('-c', '--cfile', action="store")
+args = parser.parse_args()
+
+sys.path.append(".")
+
+inputfile = args.inputfile.replace('.py', '')
+cfg = importlib.import_module(inputfile, package=None)
+
+# https://docs.python.org/3/library/struct.html
+format_struct = {'u8': 'B',
+                 'u16' : 'H',
+                 'u32' : 'I',
+                 'i32' : 'i',
+                 'u64' : 'Q',
+                 'f64' : 'd',
+                 'vl_api_ip4_fib_counter_t' : 'IBQQ',
+                 'vl_api_ip6_fib_counter_t' : 'QQBQQ',
+                 };
+type_size = {'u8':   1,
+             'u16' : 2,
+             'u32' : 4,
+             'i32' : 4,
+             'u64' : 8,
+             'f64' : 8,
+             'vl_api_ip4_fib_counter_t' : 21,
+             'vl_api_ip6_fib_counter_t' : 33,
+};
+
+def get_args(t):
+    args = None
+    for i in t:
+        arg = i[1]
+        arg = arg.replace('_','')
+        if args == None:
+            args = arg
+            continue
+        args = args + ', ' +  arg
+    return args
+
+def get_pack(t):
+    bytecount = 0
+    pack = '>'
+    tup = u''
+    j = -1
+    for i in t:
+        j += 1
+        if len(i) is 3:
+            size = type_size[i[0]]
+            bytecount += size * int(i[2])
+            if i[2] == '0':
+                tup += 'msg[' + str(bytecount) + ':],'
+                continue
+            if size == 1:
+                n = i[2] * size
+                pack += str(n) + 's'
+                tup += 'tr[' + str(j) + '],'
+                continue
+            pack += format_struct[i[0]] * int(i[2])
+            tup += 'tr[' + str(j) + ':' + str(j + int(i[2])) + '],'
+            j += int(i[2]) - 1
+        else:
+            bytecount += type_size[i[0]]
+            pack += format_struct[i[0]]
+            tup += 'tr[' + str(j) + '],'
+    return pack, bytecount, tup
+
+def get_reply_func(f):
+    if f['name']+'_reply' in func_name:
+        return func_name[f['name']+'_reply']
+    if f['name'].find('_dump') > 0:
+        r = f['name'].replace('_dump','_details')
+        if r in func_name:
+            return func_name[r]
+    return None
+
+def get_enums():
+    # Read enums from stdin
+    enums_by_name = {}
+    enums_by_index = {}
+    i = 1
+    for l in sys.stdin:
+        l = l.replace(',\n','')
+        print l, "=", i
+
+        l = l.replace('VL_API_','').lower()
+        enums_by_name[l] = i
+        enums_by_index[i] = l
+
+        i += 1
+    return enums_by_name, enums_by_index
+
+def get_definitions():
+    # Pass 1
+    func_list = []
+    func_name = {}
+    i = 1
+    for a in cfg.vppapidef:
+        pack, packlen, tup = get_pack(a[1:])
+        func_name[a[0]] = dict([('name', a[0]), ('args', get_args(a[4:])), ('full_args', get_args(a[1:])), ('pack', pack), ('packlen', packlen), ('tup', tup)])
+        func_list.append(func_name[a[0]])  # Indexed by name
+    return func_list, func_name
+
+def generate_c_macros(func_list, enums_by_name):
+    file = open(args.cfile, 'w+')
+    print >>file, "#define foreach_api_msg \\"
+    for f in func_list:
+        if not f['name'] in enums_by_name:
+            continue
+        print >>file, "_(" + f['name'].upper() + ", " + f['name'] + ") \\"
+    print >>file, '''
+void pneum_set_handlers(void) {
+#define _(N,n)							\\
+  api_func_table[VL_API_##N] = sizeof(vl_api_##n##_t);
+  foreach_api_msg;
+#undef _
+}
+    '''
+
+#
+# XXX:Deal with empty arrays
+# Print array with a hash of 'decode' and 'multipart'
+# Simplify to do only decode for now. And deduce multipart from _dump?
+#
+def decode_function_print(name, args, pack, packlen, tup):
+
+    print(u'def ' + name + u'_decode(msg):')
+    print(u"    n = namedtuple('" + name + "', '" + args + "')" +
+    '''
+    if not n:
+        return None
+    ''')
+    print(u"    tr = unpack('" + pack + "', msg[:" + str(packlen) + "])")
+    print(u"    r = n._make((" + tup + "))" +
+    '''
+    if not r:
+        return None
+    return r
+    ''')
+
+def function_print(name, id, args, pack, multipart):
+    if not args:
+        args = ""
+        print "def", name + "(async = False):"
+    else:
+        print "def", name + "(" + args + ",async = False):"
+    print "    global waiting_for_reply"
+    print "    context = get_context(" + id + ")"
+
+    print '''
+    results[context] = {}
+    results[context]['e'] = threading.Event()
+    results[context]['e'].clear()
+    results[context]['r'] = []
+    waiting_for_reply = True
+    '''
+    if multipart == True:
+        print "    results[context]['m'] = True"
+
+    print "    vpp_api.write(pack('" + pack + "', " + id + ", 0, context, " + args + "))"
+
+    if multipart == True:
+        print "    vpp_api.write(pack('>HII', VL_API_CONTROL_PING, 0, context))"
+
+    print '''
+    if not async:
+        results[context]['e'].wait(5)
+        return results[context]['r']
+    return context
+    '''
+
+#
+# Should dynamically create size
+#
+def api_table_print (name, msg_id):
+    f = name + '_decode'
+    print('api_func_table[' + msg_id + '] = ' + f)
+
+#
+# Generate the main Python file
+#
+
+print '''#!/usr/bin/env python3
+
+import sys, time, threading, signal, os, logging
+from struct import *
+from collections import namedtuple
+
+#
+# Import C API shared object
+#
+import vpp_api
+
+context = 0
+results = {}
+waiting_for_reply = False
+
+#
+# XXX: Make this return a unique number
+#
+def get_context(id):
+    global context
+    context += 1
+    return context
+
+def msg_handler(msg):
+    global result, context, event_callback, waiting_for_reply
+    if not msg:
+        logging.warning('vpp_api.read failed')
+        return
+
+    id = unpack('>H', msg[0:2])
+    logging.debug('Received message', id[0])
+    if id[0] == VL_API_RX_THREAD_EXIT:
+        logging.info("We got told to leave")
+        return;
+
+    #
+    # Decode message and returns a tuple.
+    #
+    logging.debug('api_func', api_func_table[id[0]])
+    r = api_func_table[id[0]](msg)
+    if not r:
+        logging.warning('Message decode failed', id[0])
+        return
+
+    if 'context' in r._asdict():
+        if r.context > 0:
+            context = r.context
+
+    #
+    # 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?
+    #
+    logging.debug('R:', context, r, waiting_for_reply)
+    if waiting_for_reply == False:
+        event_callback(r)
+        return
+
+    #
+    # Collect results until control ping
+    #
+    if id[0] == VL_API_CONTROL_PING_REPLY:
+        results[context]['e'].set()
+        waiting_for_reply = False
+        return
+    if not context in results:
+        logging.warning('Not expecting results for this context', context)
+        return
+    if 'm' in results[context]:
+        results[context]['r'].append(r)
+        return
+
+    results[context]['r'] = r
+    results[context]['e'].set()
+    waiting_for_reply = False
+
+def connect(name):
+    signal.alarm(3) # 3 second
+    rv = vpp_api.connect(name, msg_handler)
+    signal.alarm(0)
+    logging.info("Connect:", rv)
+    return rv
+
+def disconnect():
+    rv = vpp_api.disconnect()
+    logging.info("Disconnected")
+    return rv
+
+def register_event_callback(callback):
+    global event_callback
+    event_callback = callback
+'''
+
+enums_by_name, enums_by_index = get_enums()
+func_list, func_name = get_definitions()
+
+#
+# Not needed with the new msg_size field.
+# generate_c_macros(func_list, enums_by_name)
+#
+
+pp = pprint.PrettyPrinter(indent=4)
+#print 'enums_by_index =', pp.pprint(enums_by_index)
+#print 'func_name =', pp.pprint(func_name)
+
+# Pass 2
+
+#
+# 1) The VPE API lacks a clear definition of what messages are reply messages
+# 2) Length is missing, and has to be pre-known or in case of variable sized ones calculated per message type
+#
+for f in func_list:
+    #if f['name'].find('_reply') > 0 or f['name'].find('_details') > 0:
+    decode_function_print(f['name'], f['full_args'], f['pack'], f['packlen'], f['tup'])
+
+    #r = get_reply_func(f)
+    #if not r:
+    #    #
+    #    # XXX: Functions here are not taken care of. E.g. events
+    #    #
+    #    print('Missing function', f)
+    #    continue
+
+    if f['name'].find('_dump') > 0:
+        f['multipart'] = True
+    else:
+        f['multipart'] = False
+    msg_id_in = 'VL_API_' + f['name'].upper()
+    function_print(f['name'], msg_id_in, f['args'], f['pack'], f['multipart'])
+
+
+print "api_func_table = [0] * 10000"
+for f in func_list:
+    #    if f['name'].find('_reply') > 0 or f['name'].find('_details') > 0:
+    msg_id_in = 'VL_API_' + f['name'].upper()
+    api_table_print(f['name'], msg_id_in)