gnmi_cli - Tool updte

[renukamanavalan]

Why I did it

To make the tool usable in scripting environment

How I did it

When configured via args:

• Write responses only to a o/p file instead of stdout.
• For on change events, filter for a specific event.
• Exit upon receiving N responses.
• Exit upon timeout.

The above would help use gnmi_cli as tool in scripting environment that does testing.

Sample Usage:
To receive any/all event until killed:
gnmi_cli -client_types=gnmi -a 127.0.0.1:50051 -t EVENTS -logtostderr -insecure -v 7 -qt s -q all[heartbeat=5] -streaming_type ON_CHANGE

To receive events to a file:
Add "-output_file=<file>"

To filter out for specific event:
Add "-expected_event=<event module:event tag>"

e.g. "-expected_event=sonic-events-bgp:bgp-state"

To read N events and exit
Add "-expected_count <N>"

To run with a max timeout:
Add "-streaming_timeout 10"

The following cmd will run the tool until it receives 5 test events or timeout upon 10s, whichever is earlier and receives events are written into file "/tmp/ee".

gnmi_cli -client_types=gnmi -a 127.0.0.1:50051 -t EVENTS -logtostderr -insecure -v 7 -qt s -q all[heartbeat=5] -streaming_type ON_CHANGE -output_file=/tmp/ee -expected_event=":test-tag" -expected_count 5 -streaming_timeout 10

How to verify it

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

• 201811
• 201911
• 202006
• 202012
• 202106
• 202111

Description for the changelog

Link to config_db schema for YANG module changes

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