lldp-show: skip containers not in running state

[mprabhu-nokia]

With sonic-net/sonic-buildimage#7477 asic-dependent containers are created/started only when the ASIC is detected by the platform. The lldp show command throws exception/errors if some containers are not present.

What I did

Add an additional check for container to be in running state before processing additional container state information.

How I did it

Introduced a is_instance_running() routine which will use docker-inspect to check for the state of the container.

How to verify it

Verified using lldp show table command

Previous command output (if the output of a command-line utility has changed)

admin@Linecard3:~$ show lldp table
Error response from daemon: Container e19fbab07c3789790a38c9d3348ee7b9d766dfcdba4269ab5c2fb66a6de073d0 is not running
Error response from daemon: Container 5362b5ef03a0eabdbdf1702b4974eddf2d11b8f97901c4187a54388d16278ffa is not running
Error response from daemon: Container 2e47a66771aaa68301a05a823537912d14170371f9798347c6ce6da9bb9c9c64 is not running
Capability codes: (R) Router, (B) Bridge, (O) Other
LocalPort    RemoteDevice    RemotePortID    Capability    RemotePortDescr
-----------  --------------  --------------  ------------  -----------------
--------------------------------------------------
Total entries displayed:  0

New command output (if the output of a command-line utility has changed)

admin@Linecard3:~$ show lldp table