Object registration in python succeeds, but handlers are never invoked

[kot-begemot-uk]

I am trying to register a handler in python for a new model.

The model augments if/interfaces/interface:

augment "/if:interfaces/if:interface" {
    when "if:type = 'ianaift:l2vlan'";

It is added successfully to the models, everything is recompiled and cps.type() reports the correct information on it.

cps.type("dhcp-agent/if/interfaces/interface")
{'name': 'dhcp-agent/if/interfaces/interface', 'embedded': 'True', 'attribute_type': 'container', 'data_type': 'bin', 'key': '300.44.2883617.2883612.2883613', 'id': '19661025', 'description': ''}

I am testing the object registration for this path using the following simple python snippet:

#!/usr/bin/env python
'''DHCP Agent CPS Registration'''
import cps
import cps_utils
PATH = 'dhcp-agent/if/interfaces/interface'

def test_get(arg):
    print "test get invoked with args {}".format(arg)
    return True

class DHCPRegistration(object):
    '''CPS Registration handler for DHCP'''
     def __init__(self):
        self.handle = cps.obj_init()
        self.callback = {"get".encode('ascii'):test_get, "transaction".encode('ascii'):self.transaction}
        cps.obj_register(self.handle, PATH, self.callback)

    def get(self, arg):
        '''Get Handler'''
        print "get invoked with args {}".format(arg)

    def transaction(self, arg):
        '''Transaction Handler'''
        print "transaction invoked with args {}".format(arg)

1. cps.obj_register returns True which according to the code in the cps api means registration is OK
2. Neither the bound methods (in the object) or the simple function test_get are invoked for any transactions coming via CPS.
3. CPS returns transaction successful for transactions targeted at dhcp-agent/if/interfaces/interface (f.e. set). The method is not invoked and the data is lost along the way
4. Prior to registering an handler obj_stats() returns None. After registering an object it reports the same information for any path so the available debug info is not particularly informative.

[rakeshdatta]

I did an exercise myself in 2.3.1 to see what’s going on.. Everything seems to be all right. Can u plz follow the steps below and see if you’re good. Let me know.

• Clone opx-build.
• Clone opx-base-model.
• cd opx-base-model; git checkout v2.3.1
• Create the dell-test.yang (attached) file in opx-base-model/yang-models.
• add this new yang file in the opx-base-model/Makefile.am (attached).
• increase the version to “+rakesh” in the debian/changelog and configure.ac (attached) [use any string you want instead of “+rakesh”].
• build the opx-base-model (“DIST=jessie OPX_RELEASE=2.3.1 opx-build/scripts/opx_run opx_build opx-base-model”) from the top level dir where the opx repos reside.
• scp “pool/jessie-amd64/opx-base-model/libopx-base-model1_3.112.0+rakesh_amd64.deb” to the OPX 2.3.1 box and install it
• Get into the root mode.
• Check if you see the *.so corresponding to this new yang file, in the ‘/usr/lib/x86_64-linux-gnu/ ’ directory. If not, reboot the box and re-check.
• Try ‘cps_get_oid.py -qua target test/if/interfaces/interface’. You should get an error since there is no callback registered.
• Try ‘cps_set_oid.py -oper set test/if/interfaces/interface’. You should get an error since there is no callback registered.
• Copy the server code (test-server.py attached) into the box, that registers the cps callbacks, and start it in background: ‘sudo python test-server.py &’
• Try ‘cps_get_oid.py -qua target test/if/interfaces/interface’. You should see the ‘GET_CB invoked’ debug message.
• Try ‘cps_set_oid.py -oper set test/if/interfaces/interface’. You should see the ‘TRANS_CB invoked’ debug message.

There are multiple reasons your code may not be working:

• You have used the object path instead of key in the cps.obj_register()
• You are not letting the server app keep running continuously.
• Etc.

rdatta@netlogin-eqx-01:/neteng/rdatta/github-issues/84_cps_obj_reg$ cat test_server.py
#!/usr/bin/env python

import cps
import cps_utils
import time

PATH = "test/if/interfaces/interface"


def get_cb(method, params):
        print "GET_CB is invoked"

        return TRUE



def trans_cb(method, params):
        print "TRANS_CB invoked"

        return TRUE


if __name__ == '__main__':
        dict_cb = {}
        dict_cb['get'] = get_cb
        dict_cb['transaction'] = trans_cb

        handle = cps.obj_init()

        cps.obj_register(handle, cps.key_from_name("target", PATH) , dict_cb)

        while True:
                time.sleep(1)

rdatta@netlogin-eqx-01:/neteng/rdatta/github-issues/84_cps_obj_reg/opx-base-model$ git diff
diff --git a/configure.ac b/configure.ac
index 18ae828..9e5b32c 100644
--- a/configure.ac
+++ b/configure.ac
@@ -1,7 +1,7 @@
 #                                               -*- Autoconf -*-
 # Process this file with autoconf to produce a configure script.
 AC_PREREQ([2.69])
-AC_INIT([opx-base-model], [3.112.0], [[email protected]])
+AC_INIT([opx-base-model], [3.112.0+rakesh], [[email protected]])
 AM_INIT_AUTOMAKE([foreign subdir-objects])
 AC_CONFIG_SRCDIR([yang-models])
 AC_CONFIG_HEADERS([config.h])
diff --git a/debian/changelog b/debian/changelog
index 073113c..0d22131 100644
--- a/debian/changelog
+++ b/debian/changelog
@@ -1,3 +1,9 @@
+opx-base-model (3.112.0+rakesh) unstable; urgency=medium
+
+  * Update: Test
+
+ -- Dell EMC <[email protected]>  Mon, 23 Jul 2018 16:00:00 -0800
+
 opx-base-model (3.112.0) unstable; urgency=medium

   * Update: Adding ip-mtu to interface state attribute
rdatta@netlogin-eqx-01:/neteng/rdatta/github-issues/84_cps_obj_reg/opx-base-model$ git status
HEAD detached at v2.3.1
Changes to be committed:
  (use "git reset HEAD <file>..." to unstage)

        modified:   Makefile.am
        new file:   yang-models/dell-test.yang

Changes not staged for commit:
  (use "git add <file>..." to update what will be committed)
  (use "git checkout -- <file>..." to discard changes in working directory)

        modified:   configure.ac
        modified:   debian/changelog

rdatta@netlogin-eqx-01:/neteng/rdatta/github-issues/84_cps_obj_reg/opx-base-model$ git diff --staged
diff --git a/Makefile.am b/Makefile.am
index 3b61e74..5ca6fd0 100644
--- a/Makefile.am
+++ b/Makefile.am
@@ -27,6 +27,7 @@ YANG_PARSED_FILES = \
     $(top_srcdir)/yang-models/dell-base-packet.yang \
     $(top_srcdir)/yang-models/dell-base-interface-common.yang \
     $(top_srcdir)/yang-models/dell-base-ip.yang \
+    $(top_srcdir)/yang-models/dell-test.yang \
     $(top_srcdir)/yang-models/dell-base-qos.yang \
     $(top_srcdir)/yang-models/dell-base-l2-mac.yang \
     $(top_srcdir)/yang-models/dell-base-if-phy.yang \
@@ -94,6 +95,7 @@ YANG_GENERATED_SRCS = \
     @YANG_OUTPUT@/dell-base-packet.cpp \
     @YANG_OUTPUT@/dell-base-interface-common.cpp \
     @YANG_OUTPUT@/dell-base-ip.cpp \
+    @YANG_OUTPUT@/dell-test.cpp \
     @YANG_OUTPUT@/dell-base-qos.cpp \
     @YANG_OUTPUT@/dell-base-l2-mac.cpp \
     @YANG_OUTPUT@/dell-base-if-phy.cpp \
@@ -157,6 +159,7 @@ YANG_GENERATED_HDRS = \
     @YANG_OUTPUT@/dell-base-packet.h \
     @YANG_OUTPUT@/dell-base-interface-common.h \
     @YANG_OUTPUT@/dell-base-ip.h \
+    @YANG_OUTPUT@/dell-test.h \
     @YANG_OUTPUT@/dell-base-qos.h \
     @YANG_OUTPUT@/dell-base-l2-mac.h \
     @YANG_OUTPUT@/dell-base-if-phy.h \
@@ -224,6 +227,7 @@ lib_LTLIBRARIES = \
     libcpsclass_dell-base-packet.la \
     libcpsclass_dell-base-interface-common.la \
     libcpsclass_dell-base-ip.la \
+    libcpsclass_dell-test.la \
     libcpsclass_dell-base-qos.la \
     libcpsclass_dell-base-l2-mac.la \
     libcpsclass_dell-base-if-phy.la \
@@ -345,6 +349,9 @@ libcpsclass_dell_base_interface_common_la_LIBADD = -lopx_cps_class_map -lopx_cps
 libcpsclass_dell_base_ip_la_SOURCES = @YANG_OUTPUT@/dell-base-ip.cpp
 libcpsclass_dell_base_ip_la_LIBADD = -lopx_cps_class_map -lopx_cps_api_common

+libcpsclass_dell_test_la_SOURCES = @YANG_OUTPUT@/dell-test.cpp
+libcpsclass_dell_test_la_LIBADD = -lopx_cps_class_map -lopx_cps_api_common
+
 libcpsclass_dell_base_qos_la_SOURCES = @YANG_OUTPUT@/dell-base-qos.cpp
 libcpsclass_dell_base_qos_la_LIBADD = -lopx_cps_class_map -lopx_cps_api_common

diff --git a/yang-models/dell-test.yang b/yang-models/dell-test.yang
new file mode 100644
index 0000000..bdfdb2e
--- /dev/null
+++ b/yang-models/dell-test.yang
@@ -0,0 +1,34 @@
+module dell-test {
+    namespace "http://www.dellemc.com/networking/os10/dell-test";
+
+    prefix "test";
+
+    import ietf-interfaces {
+        prefix "if";
+    }
+
+    import dell-base-common {
+        prefix "base-cmn";
+    }
+
+    organization "Dell EMC";
+
+    contact "http://www.dell.com/support";
+
+    description "This is a test module";
+
+    revision 2018-07-20 {
+        description
+            "This is a test module";
+        reference
+            "Network Platform Abstraction";
+    }
+
+    augment "/if:interfaces/if:interface" {
+        leaf test-node {
+            type base-cmn:vlan-id;
+            description "test id";
+        }
+    }
+}
+
(END)

[kot-begemot-uk]

I think this needs reopening.
While all examples are correct and the callback gets invoked, that does not actually perform an augment.
They are invoked ONLY if the node test/if/interfaces/interface is accessed directly.
If you access the augmented node (should be if/interfaces/interface, but for whatever reason it's dhcp-agent/if/interfaces/interface/dhcp-server), the callback is not invoked. So in fact, the augment does not work as intended.

[jeff-yin]

@rakeshdatta will follow up