VPP Python language binding - plugin support

- Moved Python generator tool to tools directory
- Added build-vpp-api Makefile target
- Generator now only creates a Python representation of the .api
  the rest of the framework is in the vpp_papi script
- Each plugin has its own namespace.
- Plugin Python files are installed in vpp_papi_plugins for easy
  use inside the build tree.

Change-Id: I272c83bb7e5d5e416bdbd8a790a3cc35c5a04e38
Signed-off-by: Ole Troan <ot@cisco.com>

1 files changed, 155 insertions, 0 deletions

diff --git a/vpp-api/python/vpp_papi/vpp_papi.py b/vpp-api/python/vpp_papi/vpp_papi.py
new file mode 100644
index 00000000000..6a7a358f6cd
--- /dev/null
+++ b/vpp-api/python/vpp_papi/vpp_papi.py
@@ -0,0 +1,155 @@
+#
+# 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 C API shared object
+#
+from __future__ import print_function
+
+import signal, logging, os, sys
+from struct import *
+
+scriptdir = os.path.dirname(os.path.realpath(__file__))
+sys.path.append(scriptdir)
+import vpp_api
+from vpp_api_base import *
+
+# Import API definitions. The core VPE API is imported into main namespace
+import memclnt
+from vpe import *
+vpe = sys.modules['vpe']
+
+def msg_handler(msg):
+    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] == memclnt.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?
+    #
+    if not is_waiting_for_reply():
+        event_callback_call(r)
+        return
+
+    #
+    # Collect results until control ping
+    #
+    if id[0] == vpe.VL_API_CONTROL_PING_REPLY:
+        results_event_set(context)
+        waiting_for_reply_clear()
+        return
+    if not is_results_context(context):
+        logging.warning('Not expecting results for this context', context)
+        return
+    if is_results_more(context):
+        results_append(context, r)
+        return
+
+    results_set(context, r)
+    results_event_set(context)
+    waiting_for_reply_clear()
+
+def connect(name):
+    signal.alarm(3) # 3 second
+    rv = vpp_api.connect(name, msg_handler)
+    signal.alarm(0)
+    logging.info("Connect:", rv)
+
+    #
+    # Assign message id space for plugins
+    #
+    plugin_map_plugins()
+
+    return rv
+
+def disconnect():
+    rv = vpp_api.disconnect()
+    logging.info("Disconnected")
+    return rv
+
+def register_event_callback(callback):
+    event_callback_set(callback)
+
+def plugin_name_to_id(plugin, name_to_id_table, base):
+    try:
+        m = globals()[plugin]
+    except KeyError:
+        m = sys.modules[plugin]
+    for name in name_to_id_table:
+        setattr(m, name, name_to_id_table[name] + base)
+
+def plugin_map_plugins():
+    for p in plugins:
+        if p == 'memclnt' or p == 'vpe':
+            continue
+
+        #
+        # Find base
+        # Update api table
+        #
+        version = plugins[p]['version']
+        name = p + '_' + format(version, '08x')
+        r = memclnt.get_first_msg_id(name.encode('ascii'))
+
+        ## TODO: Add error handling
+        if r.retval != 0:
+            print('Failed getting first msg id for:', p)
+            continue
+
+        # Set base
+        base = r.first_msg_id
+        msg_id_base_set = plugins[p]['msg_id_base_set']
+        msg_id_base_set(base)
+        plugins[p]['base'] = base
+        func_table = plugins[p]['func_table']
+        i = r.first_msg_id
+        for entry in func_table:
+            api_func_table.insert(i, entry)
+            i += 1
+        plugin_name_to_id(p, plugins[p]['name_to_id_table'], base)
+
+#
+# Set up core API
+#
+memclnt.msg_id_base_set(1)
+plugins['memclnt']['base'] = 1
+msg_id_base_set(len(plugins['memclnt']['func_table']) + 1)
+plugins['vpe']['base'] = len(plugins['memclnt']['func_table']) + 1
+api_func_table = []
+api_func_table.append(None)
+api_func_table[1:] = plugins['memclnt']['func_table'] + plugins['vpe']['func_table']
+plugin_name_to_id('memclnt', plugins['memclnt']['name_to_id_table'], 1)
+plugin_name_to_id('vpe', plugins['vpe']['name_to_id_table'], plugins['vpe']['base'])
+#logging.basicConfig(level=logging.DEBUG)