[sFlow] Fix sFlow CLI cannot use parameter "all" to disable sFlow on all interfaces.

[steven-guo-ec]

• What I did
  Fix the following issue that CLI command cannot use parameter "all" to disable sFlow on all interfaces.

admin@sonic:~$ show sflow interface

sFlow interface configurations
+-------------+---------------+-----------------+
| Interface   | Admin State   | Sampling Rate   |
+=============+===============+=================+
+-------------+---------------+-----------------+
admin@sonic:~$ sudo config sflow interface enable Ethernet0
admin@sonic:~$ show sflow interface

sFlow interface configurations
+-------------+---------------+-----------------+
| Interface   | Admin State   |   Sampling Rate |
+=============+===============+=================+
| Ethernet0   | up            |           10000 |
+-------------+---------------+-----------------+
admin@sonic:~$ sudo config sflow interface disable all
admin@sonic:~$ show sflow interface

sFlow interface configurations
+-------------+---------------+-----------------+
| Interface   | Admin State   |   Sampling Rate |
+=============+===============+=================+
| Ethernet0   | up            |           10000 |
+-------------+---------------+-----------------+
admin@sonic:~$

When configuring sFlow on all interface, expand the sFlow to all interface instead of add a 'SFLOW_SESSION|all' entry in CONFIG_DB.

• Why I did it
  The 'all' parameter in 'config sflow interface' command doesn't work to disable sFlow on all interfaces.

• How I verified it
  Verified the change by following testing procedures:

  • Enable on an interface -> enable all interfaces
  • Enable on an interface -> disable all interfaces
  • Disable on an interface -> enable all interfaces
  • Disable on an interface -> disable all interfaces
  • Enable all interfaces -> enable on an interface
  • Enable all interfaces -> disable on an interface
  • Disable all interfaces -> enable on an interface
  • Disable all interfaces -> disable on an interface

[liat-grozovik]

@vivekreddynv can you please review?

[vivekrnv]

Hi @steven-guo-ec,

This is an expected behavior i.e. local config takes precedence over global config, so there's nothing to fix here. This is not documented in the HLD. I've raised a PR to document this behavior. PR

[liat-grozovik]

@dgsudharsan could you please help to review this one?

[dgsudharsan]

@liat-grozovik As Vivek explained this is an expected behavior. We updated the HLD. The PR is not needed and I would recommend the author to close this PR

[liat-grozovik]

thanks. i missed it.

[steven-guo-ec]

Got it, thanks.