updated jinja template for snmp contact python2 vs python3 issue

[tsvanduyn]

Why I did it

The SNMP contact was not generating correctly when a docker container was restarted.

How I did it

Root Cause:
This was an incompatibility between python2 vs python3.

Type "help", "copyright", "credits" or "license" for more information.
>>> from swsssdk import ConfigDBConnector, SonicV2Connector, SonicDBConfig
>>> config_db = ConfigDBConnector()
>>> config_db.connect()
>>> SNMP = config_db.get_table('SNMP')
>>> SNMP['CONTACT'].keys()[0]
'SN:MT2115X12126;Asset:12518181;PIN:mls-dla_tor_leaf;'
>>>


Python3
>>> config_db = ConfigDBConnector()
>>> config_db.connect()
>>> SNMP = config_db.get_table('SNMP')
>>> SNMP 
{'LOCATION': {'Location': 'public'}, 'CONTACT': {'SN:MT2115X12126;Asset:12518181;PIN:mls-dla_tor_leaf;': '[email protected]'}}
>>> 
>>> 
>>> 
>>> SNMP['CONTACT']
{'SN:MT2115X12126;Asset:12518181;PIN:mls-dla_tor_leaf;': '[email protected]'}
>>> SNMP['CONTACT'].keys()
dict_keys(['SN:MT2115X12126;Asset:12518181;PIN:mls-dla_tor_leaf;'])
>>> SNMP['CONTACT'].keys()[0]
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
TypeError: 'dict_keys' object is not subscriptable


So I did some tests and this is how it needs to be fixed to work in python3.
{% if SNMP is defined and SNMP.CONTACT is defined %}
sysContact     {{ SNMP.CONTACT.keys() | first }} {{ SNMP.CONTACT.values() | first }}
{% else %}
sysContact     Azure Cloud Switch vteam [[email protected]](mailto:[email protected])
{% endif %}

How to verify it

I tested this in a lab device and it all worked as expected.
Once the Jinja2 template was updated.

Before

root@str-s6100-acs-1:/usr/share/sonic/templates# cat snmpd.conf.j2 | grep -a10 -i contact
#

#  Note that setting these values here, results in the corresponding MIB objects being 'read-only'
#  See snmpd.conf(5) for more details

{% if SNMP is defined and SNMP.LOCATION is defined %}
sysLocation    {{ SNMP.LOCATION.Location }}
{% else %}
sysLocation    public
{% endif %}
{% if SNMP is defined and SNMP.CONTACT is defined %}
sysContact     {{ SNMP.CONTACT.keys()[0] }} {{ SNMP.CONTACT.values()[0] }}
{% else %}
sysContact     Azure Cloud Switch vteam <[email protected]>
{% endif %}

                                                 # Application + End-to-End layers
sysServices    72


#
#  Process Monitoring
#
# todo: should we enable snmp based monitoring of sswsyncd and other processes?
root@str-s6100-acs-1:/usr/share/sonic/templates# 

Before test:

admin@str-s6100-acs-1:~$ show run snmp contact
Contact                                              Contact Email
---------------------------------------------------  -----------------------
SN:MT2115X12126;Asset:12518181;PIN:mls-dla_tor_leaf  [email protected]
admin@str-s6100-acs-1:~$ 


trvanduy@nettools4-eastus2:~$ snmpget -v 2c -c Test1 str-s6100-acs-1 sysContact.0
SNMPv2-MIB::sysContact.0 = STRING: root

After

root@str-s6100-acs-1:/usr/share/sonic/templates# cat snmpd.conf.j2 | grep -a10 -i contact
#

#  Note that setting these values here, results in the corresponding MIB objects being 'read-only'
#  See snmpd.conf(5) for more details

{% if SNMP is defined and SNMP.LOCATION is defined %}
sysLocation    {{ SNMP.LOCATION.Location }}
{% else %}
sysLocation    public
{% endif %}
{% if SNMP is defined and SNMP.CONTACT is defined %}
sysContact     {{ SNMP.CONTACT.keys() | first }} {{ SNMP.CONTACT.values() | first }}
{% else %}
sysContact     Azure Cloud Switch vteam <[email protected]>
{% endif %}

                                                 # Application + End-to-End layers
sysServices    72


#
#  Process Monitoring
#
# todo: should we enable snmp based monitoring of sswsyncd and other processes?
root@str-s6100-acs-1:/usr/share/sonic/templates# 

After test:

admin@str-s6100-acs-1:~$ show run snmp contact
Contact                                              Contact Email
---------------------------------------------------  -----------------------
SN:MT2115X12126;Asset:12518181;PIN:mls-dla_tor_leaf  [email protected]
admin@str-s6100-acs-1:~$ 


trvanduy@nettools4-eastus2:~$ snmpget -v 2c -c Test1 str-s6100-acs-1 sysContact.0
SNMPv2-MIB::sysContact.0 = STRING: SN:MT2115X12126;Asset:12518181;PIN:mls-dla_tor_leaf [email protected]

If there is no contact after the fix

admin@str-s6100-acs-1:~$ show run snmp contact
Contact    Contact Email
---------  ---------------
admin@str-s6100-acs-1:~$ 

trvanduy@nettools4-eastus2:~$ snmpget -v 2c -c Test1 str-s6100-acs-1 sysContact.0
SNMPv2-MIB::sysContact.0 = STRING: Azure Cloud Switch vteam <[email protected]>
trvanduy@nettools4-eastus2:~$ 

Which release branch to backport (provide reason below if selected)

• 201811
• 201911
• 202006
• 202012
• 202106

We should backport to these branches that have the feature enabled to use the new snmp commands.

Description for the changelog

A picture of a cute animal (not mandatory but encouraged)