[sonic-utilities] fix config/show vlan members

[dawnbeauty]

- What I did
fixes Azure/SONiC issue 323

- How I did it
As the issue mentioned, the "members@" field of VLAN is for backward compatibility.
Utility script should no longer use it when config add/del vlan members.

• config add vlan members
  pre-add: check "members" of given vlan entry and vlan members table to ensure that the interface is not a member of given vlan.
  add: add interface to VLAN_MEMBER table. (not to "members" of vlan.)

• config del vlan members
  pre-del: check "members" of given vlan entry and vlan members table to ensure that the interface is a member of given vlan.
  del: not only remove interface from VLAN_MEMBER table but also from "members" of vlan(if existing)

• show vlan config
  collect members info from "members" list of given vlan and VLAN_MEMBER_TABLE.

- How to verify it
assume boot with below vlan configuration in config_db.json

    "VLAN": {
        "Vlan100": {
            "vlanid": "100"
        },
        "Vlan200": {
            "vlanid": "200"
        }
    },
    "VLAN_MEMBER": {
        "Vlan100|Ethernet0": {
            "tagging_mode": "untagged"
        },
        "Vlan100|Ethernet1": {
            "tagging_mode": "untagged"
        },
        "Vlan200|Ethernet2": {
            "tagging_mode": "tagged"
        },
        "Vlan200|Ethernet3": {
            "tagging_mode": "tagged"
        }
    }

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

• show

admin@sonic:~$ show vlan brief
+-----------+-------------------+-----------+----------------+-----------------------+
|   VLAN ID | IP Address        | Ports     | Port Tagging   | DHCP Helper Address   |
+===========+===================+===========+================+=======================+
|       100 | 10.1.1.1/24       | Ethernet0 | untagged       |                       |
|           | 2000::10:1:1:1/80 | Ethernet1 | untagged       |                       |
+-----------+-------------------+-----------+----------------+-----------------------+
|       200 | 20.1.1.1/24       | Ethernet2 | tagged         |                       |
|           | 2000::20:1:1:1/80 | Ethernet3 | tagged         |                       |
+-----------+-------------------+-----------+----------------+-----------------------+
admin@sonic:~$ show vlan config
Name       VID
-------  -----
Vlan100    100
Vlan200    200

NOTICE: here we could not get vlan member output from show vlan config

• config del vlan member

admin@sonic:~$ sudo config vlan member del 100 Ethernet0
Usage: config vlan member del [OPTIONS] <vid> <interface_name>

Error: Ethernet0 is not a member of Vlan100

• config add vlan member

sudo config vlan member add 100 Ethernet4
admin@sonic:~$ redis-cli -n 4 hgetall "VLAN|Vlan100" 
1) "vlanid"
2) "100"
3) "members@"
4) "Ethernet4"

admin@sonic:~$ show vlan config
Name       VID  Member     Mode
-------  -----  ---------  ------
Vlan100    100  Ethernet4  tagged
Vlan200    200

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

• show

admin@sonic:~$ show vlan config
Name       VID  Member     Mode
-------  -----  ---------  --------
Vlan100    100  Ethernet0  untagged
Vlan100    100  Ethernet1  untagged
Vlan200    200  Ethernet2  tagged
Vlan200    200  Ethernet3  tagged

• config del vlan member

admin@sonic:~$ sudo config vlan member del 100 Ethernet0
admin@sonic:~$ show vlan config
Name       VID  Member     Mode
-------  -----  ---------  --------
Vlan100    100  Ethernet1  untagged
Vlan200    200  Ethernet2  tagged
Vlan200    200  Ethernet3  tagged

• config add vlan member

admin@sonic:~$ sudo config vlan member add 100 Ethernet4
admin@sonic:~$ redis-cli -n 4 hgetall "VLAN|Vlan100"                
1) "vlanid"
2) "100"
admin@sonic:~$ show vlan config
Name       VID  Member     Mode
-------  -----  ---------  --------
Vlan100    100  Ethernet1  untagged
Vlan100    100  Ethernet4  tagged
Vlan200    200  Ethernet2  tagged
Vlan200    200  Ethernet3  tagged

[prsunny]

Can you update the description with previous and new output?

[jleveque]

@dawnbeauty: Can you update the description with previous and new output?

[dawnbeauty]

@prsunny @jleveque Updated comments. Please review again, thanks.

[jleveque]

@dawnbeauty: Thanks. Can you also fix the recent merge conflict?

[dawnbeauty]

Done.

[jleveque]

Retest this please

[prsunny]

So command is no longer updating "members" field of VLAN table during add, correct?. Lgtm!

[lguohan]

obsoleted by #1050

[dawnbeauty]

@lguohan #1050 only fix the show commands, how about the add/del actions?