Fix the issue when persistent DVS is used to run pytest which has number of front-panel ports < 32

[abdosi]

Why/What I did
Fix the issue where persistent DVS is used to run pytest
and ports are created dynamically (ref pr#
sonic-net/sonic-buildimage#4499). There were two
issues:

a) since number of dynamic front port can be < 32 test case fails
   as it expect always 32. Make sure to update persistent DVS to always have
   32 ports/server link as part of test run if forcedvs option provided else abort test case 
   and save the current config db

b) after test is done persistent DVS need to be moved to original state.
   Make sure to remove extra port/server link and restore back config db

How I verified it

a) Verified Persistent DVS < 32 ports without forcedvs option then abort else DVS restarted with 32 ports.
b) Manually Verified VS Docker has correct interface config/port.ini/ip link after test is completed and restored original config db
c) Verified on host ip netns list has expected server link only after is completed

[daall]

since number of dynamic front port can be < 32 test case fails as it expect always 32

Which tests are always expecting 32 ports? I am OK with this change as a short-term fix, but I think the real issue here is that the tests are hard-coded for 32 ports instead of checking in the Config DB. We should open an issue and track this.

[abdosi]

since number of dynamic front port can be < 32 test case fails as it expect always 32

Which tests are always expecting 32 ports? I am OK with this change as a short-term fix, but I think the real issue here is that the tests are hard-coded for 32 ports instead of checking in the Config DB. We should open an issue and track this.

@daall . Many test case are using hard-coded server indexing

For eg: test_fdb_update.py we use dvs.servers[17].runcmd
test_route.py we use dvs.servers[3].runcmd

[daall]

since number of dynamic front port can be < 32 test case fails as it expect always 32

Which tests are always expecting 32 ports? I am OK with this change as a short-term fix, but I think the real issue here is that the tests are hard-coded for 32 ports instead of checking in the Config DB. We should open an issue and track this.

@daall . Many test case are using hard-coded server indexing

For eg: test_fdb_update.py we use dvs.servers[17].runcmd
test_route.py we use dvs.servers[3].runcmd

ack, I will open an issue to track this. Thanks for pointing this out!

[daall]

lgtm, please wait for @lguohan's review

[abdosi]

retest this please

[abdosi]

retest this please

[abdosi]

retest this please

[abdosi]

lgtm, please wait for @lguohan's review

@lguohan Can you please review this

[abdosi]

retest this please

[abdosi]

retest this please

[abdosi]

@lguohan can you review this.

[abdosi]

retest this please

[abdosi]

retest this please

[abdosi]

lgtm, please wait for @lguohan's review

@lguohan Can you please review this

@lguohan is it ok to merge ?

[lguohan]

maybe we can just check if persistent dvs has 32 ports, if not, then we just abort and say persistent dvs has to be 32 ports instead of reconfiguration here?

[abdosi]

maybe we can just check if persistent dvs has 32 ports, if not, then we just abort and say persistent dvs has to be 32 ports instead of reconfiguration here?

@lguohan i think it is better to keep using existing persistent dvs and we can run pytest on top of that
instead to abort it especially for local development/debugging which can have local swss debian package.

[lguohan]

@abdosi , can you provide that as an option?

@lguohan Updated with --forcedvs option . Default being abort if ports < 32
@daall

[lgtm-com]

This pull request introduces 1 alert and fixes 12 when merging d821218 into 879f45b - view on LGTM.com

new alerts:

• 1 for Syntax error

fixed alerts:

• 4 for First parameter of a method is not named 'self'
• 4 for Unused local variable
• 2 for Variable defined multiple times
• 1 for Testing equality to None
• 1 for Unnecessary 'else' clause in loop

[lgtm-com]

This pull request introduces 1 alert and fixes 12 when merging 6629b67 into 879f45b - view on LGTM.com

new alerts:

• 1 for Syntax error

fixed alerts:

• 4 for First parameter of a method is not named 'self'
• 4 for Unused local variable
• 2 for Variable defined multiple times
• 1 for Testing equality to None
• 1 for Unnecessary 'else' clause in loop

[daall]

retest vs please