acl-loader update command enhancement

[vishnushetty]

- What I did
Added incremental update for datapath acl.
To support backward incremental effect use 'load' command. Now three options for update:

full (add/delete)
incremental (add/delete/update)
load (add/update)

And fixed python3 (cmp not available).

- How I did it

- How to verify it
root@sonic:# config acl add table MYTESTACL l3
root@sonic:# config acl update full acl_rule_1_2.json
root@sonic:~# show acl rule
Table Rule Priority Action Match

---

MYTESTACL RULE_1 9999 FORWARD IP_PROTOCOL: 6
L4_DST_PORT: 22
SRC_IP: 192.168.1.1/32
MYTESTACL RULE_2 9998 DROP IP_PROTOCOL: 6
L4_DST_PORT: 22
SRC_IP: 192.168.1.2/32
MYTESTACL DEFAULT_RULE 1 DROP ETHER_TYPE: 2048
root@sonic:# config acl update incremental acl_rule_1_4.json
root@sonic:# show acl rule
Table Rule Priority Action Match

---

MYTESTACL RULE_1 9999 FORWARD IP_PROTOCOL: 6
L4_DST_PORT: 22
SRC_IP: 192.168.1.1/32
MYTESTACL RULE_2 9998 DROP IP_PROTOCOL: 6
L4_DST_PORT: 22
SRC_IP: 192.168.1.2/32
MYTESTACL RULE_3 9997 FORWARD IP_PROTOCOL: 6
L4_DST_PORT: 22
SRC_IP: 192.168.1.3/32
MYTESTACL RULE_4 9996 DROP IP_PROTOCOL: 6
L4_DST_PORT: 22
SRC_IP: 192.168.1.4/32
MYTESTACL DEFAULT_RULE 1 DROP ETHER_TYPE: 2048
root@sonic:# config acl update load acl_rule_1_4.json
root@sonic:# show acl rule
Table Rule Priority Action Match

---

MYTESTACL RULE_1 9999 FORWARD IP_PROTOCOL: 6
L4_DST_PORT: 22
SRC_IP: 192.168.1.1/32
MYTESTACL RULE_2 9998 DROP IP_PROTOCOL: 6
L4_DST_PORT: 22
SRC_IP: 192.168.1.2/32
MYTESTACL RULE_3 9997 FORWARD IP_PROTOCOL: 6
L4_DST_PORT: 22
SRC_IP: 192.168.1.3/32
MYTESTACL RULE_4 9996 DROP IP_PROTOCOL: 6
L4_DST_PORT: 22
SRC_IP: 192.168.1.4/32
MYTESTACL DEFAULT_RULE 1 DROP ETHER_TYPE: 2048
root@sonic:#
- Previous command output (if the output of a command-line utility has changed)
root@sonic:# config acl add table MYTESTACL l3
root@sonic:# config acl update full acl_rule_1_2.json
root@sonic:# show acl rule
Table Rule Priority Action Match

---

MYTESTACL RULE_1 9999 FORWARD IP_PROTOCOL: 6
L4_DST_PORT: 22
SRC_IP: 192.168.1.1/32
MYTESTACL RULE_2 9998 DROP IP_PROTOCOL: 6
L4_DST_PORT: 22
SRC_IP: 192.168.1.2/32
MYTESTACL DEFAULT_RULE 1 DROP ETHER_TYPE: 2048
root@sonic:# config acl update incremental acl_rule_1_4.json
root@sonic:# show acl rule
Table Rule Priority Action Match

---

MYTESTACL RULE_1 9999 FORWARD IP_PROTOCOL: 6
L4_DST_PORT: 22
SRC_IP: 192.168.1.1/32
MYTESTACL RULE_2 9998 DROP IP_PROTOCOL: 6
L4_DST_PORT: 22
SRC_IP: 192.168.1.2/32
MYTESTACL RULE_3 9997 FORWARD IP_PROTOCOL: 6
L4_DST_PORT: 22
SRC_IP: 192.168.1.3/32
MYTESTACL RULE_4 9996 DROP IP_PROTOCOL: 6
L4_DST_PORT: 22
SRC_IP: 192.168.1.4/32
MYTESTACL DEFAULT_RULE 1 DROP ETHER_TYPE: 2048
root@sonic:~
- New command output (if the output of a command-line utility has changed)
oot@sonic:# config acl update load acl_rule_1_4.json
root@sonic:# show acl rule
Table Rule Priority Action Match

---

MYTESTACL RULE_1 9999 FORWARD IP_PROTOCOL: 6
L4_DST_PORT: 22
SRC_IP: 192.168.1.1/32
MYTESTACL RULE_2 9998 DROP IP_PROTOCOL: 6
L4_DST_PORT: 22
SRC_IP: 192.168.1.2/32
MYTESTACL RULE_3 9997 FORWARD IP_PROTOCOL: 6
L4_DST_PORT: 22
SRC_IP: 192.168.1.3/32
MYTESTACL RULE_4 9996 DROP IP_PROTOCOL: 6
L4_DST_PORT: 22
SRC_IP: 192.168.1.4/32
MYTESTACL DEFAULT_RULE 1 DROP ETHER_TYPE: 2048

[ghost]

All CLA requirements met.

[ben-gale]

@lguohan - can we get some review pls?

[ben-gale]

@lgouhan - pls help with review of this one

[lguohan]

please add unit test

[ben-gale]

please add unit test

@lguohan - there are no existing Click unit tests for ACL loader - the only tests there are API-based UTs on the AclLoader class, and these are pretty minimal. As discussed in the past, I'm not sure how reasonable it is to ask contributors to take on the load of a full UT catch-up when adding a small change to an existing component w/o existing UT coverage. So what are you looking for here please? Thx.