OpenStack Python Client How to add new CLI command

1)
Clone python-neutronclient
#git clone https://github.com/openstack/python-neutronclient.git
#cd python-neutronclient
#git checkout 2.3.6

2)
Export the credentials
export OS_USERNAME=admin
export OS_PASSWORD=secret123
export OS_TENANT_NAME=demo
export OS_AUTH_URL=http://127.0.0.1:35357/v2.0

3)
Run the CLI command from cloned dir
#python neutron net-list
Success: Working

4)
Try to execute a command which is not implemented yet
#python neutron ipam-list
Error: Unknown command [u'ipam-list']

5)
Create command to class Mapping for our new command "ipam-list"

#vim python-neutronclient/neutronclient/shell.py
* Add the name of the command and class (command to class map) to the COMMAND_V2 dictionary

Example:
--------------
COMMAND_V2 = {
    .... ....
    'ipam-list':None,
}

COMMANDS = {'2.0': COMMAND_V2}


* Then try to run the new command "ipam-list"
#python neutron ipam-list
Error: 'NoneType' object is not callable

6)
Create a file named "ipam.py" under python-neutronclient/neutronclient/neutron/v2_0/ and add following lines

import logging
from neutronclient.neutron.v2_0 import ListCommand

class ListIpam(ListCommand):
    resource = 'ipam'
    log = logging.getLogger(__name__ + '.ListIpam')
    _formatters = {}
    list_columns = ['id', 'name']

7)
Map the command "ipam-list" to new class "ListIpam"

#vim python-neutronclient/neutronclient/shell.py

from neutronclient.neutron.v2_0 import ipam

COMMAND_V2 = {
    .... ....
    'ipam-list':ipam.ListIpam,
}

* Then try to run the command
#python neutron ipam-list
Error: 'Client' object has no attribute 'list_ipams'

8)
Add method in client class
#vim python-neutronclient/neutronclient/v2_0/client.py
This file is responsible to generate REST API requests and send the same requests to your plugin running on neutron-server.
Add following codes

class Client(object):
    .... ....
    ipams_path = "/ipams"
   
    @APIParamsCall
    def list_ipams(self, **_params):
        return self.get(self.ipams_path, params=_params)

* Then try to run the new command
#python neutron ipam-list
Sucess: Working

10)
Diff

10,a)
$ git diff
diff --git a/neutronclient/shell.py b/neutronclient/shell.py
index f1f2e2e..bda3e12 100644
--- a/neutronclient/shell.py
+++ b/neutronclient/shell.py
@@ -61,6 +61,7 @@ from neutronclient.neutron.v2_0.vpn import ikepolicy
 from neutronclient.neutron.v2_0.vpn import ipsec_site_connection
 from neutronclient.neutron.v2_0.vpn import ipsecpolicy
 from neutronclient.neutron.v2_0.vpn import vpnservice
+from neutronclient.neutron.v2_0 import ipam
 from neutronclient.openstack.common.gettextutils import _
 from neutronclient.openstack.common import strutils
 from neutronclient.version import __version__
@@ -277,6 +278,7 @@ COMMAND_V2 = {
     'nec-packet-filter-create': packetfilter.CreatePacketFilter,
     'nec-packet-filter-update': packetfilter.UpdatePacketFilter,
     'nec-packet-filter-delete': packetfilter.DeletePacketFilter,
+    'ipam-list': ipam.ListIpam,
 }

 COMMANDS = {'2.0': COMMAND_V2}
diff --git a/neutronclient/v2_0/client.py b/neutronclient/v2_0/client.py
index a102781..6b2e972 100644
--- a/neutronclient/v2_0/client.py
+++ b/neutronclient/v2_0/client.py
@@ -221,6 +221,7 @@ class Client(object):
     firewall_path = "/fw/firewalls/%s"
     net_partitions_path = "/net-partitions"
     net_partition_path = "/net-partitions/%s"
+    ipams_path = "/ipams"

     # API has no way to report plurals, so we have to hard code them
     EXTED_PLURALS = {'routers': 'router',
@@ -1187,6 +1188,14 @@ class Client(object):
         """Delete the specified packet filter."""
         return self.delete(self.packet_filter_path % packet_filter_id)

+    @APIParamsCall
+    def list_ipams(self, **_params):
+        """
+        Fetches a list of all ipams for a tenant
+        """
+        # Pass filters in "params" argument to do_request
+        return self.get(self.ipams_path, params=_params)
+
     def __init__(self, **kwargs):
         """Initialize a new client for the Neutron v2.0 API."""
         super(Client, self).__init__()
 
10,b)
#cat neutronclient/neutron/v2_0/ipam.py

import logging
from neutronclient.neutron.v2_0 import ListCommand

class ListIpam(ListCommand):
    resource = 'ipam'
    log = logging.getLogger(__name__ + '.ListIpam')
    _formatters = {}
    list_columns = ['id', 'name']

11)
Ref: http://control-that-vm.blogspot.in/2014/06/writing-cli-commands-for-neutronclient.html