"vnctl interface add" should be rolled back on errors

[miz-axsh]

vnctl interface add command with duplicated port-name parameter inserts incomplete data into the database. The series of INSERT statements should be done in one transaction, and should be rolled back on errors.

Example:

# vnctl interfaces add \
        --uuid=if-inst1x \
        --mode=vif \
        --owner-datapath-uuid=dp-dp01 \
        --mac-address 10:54:ff:00:00:01 \
        --network-uuid=nw-test1 \
        --ipv4-address=10.100.0.10 \
        --port-name=inst1  # ← inst1

# vnctl interfaces add \
        --uuid=if-inst2x \
        --mode=vif \
        --owner-datapath-uuid=dp-dp01 \
        --mac-address 10:54:ff:00:00:02 \
        --network-uuid=nw-test1 \
        --ipv4-address=10.100.0.11 \
        --port-name=inst1  # ← mistake: violates uniqueness
---
:error: Sequel::UniqueConstraintViolation
:message: 'Mysql2::Error: Duplicate entry ''inst1-1-1-0'' for key ''port_name'''
:code: 500

got an error, because port-name is duplicated.

mysql> SELECT uuid FROM interfaces;
+--------+
| uuid   |
+--------+
| inst1x |
| inst2x |
+--------+
mysql> SELECT port_name FROM interface_ports;
+-----------+
| port_name |
+-----------+
| inst1     |
+-----------+

in spite of the error, new record was inserted into the interfaces table.

# vnctl interfaces add \
        --uuid=if-inst2x \
        --mode=vif \
        --owner-datapath-uuid=dp-dp01 \
        --mac-address 10:54:ff:00:00:02 \
        --network-uuid=nw-test1 \
        --ipv4-address=10.100.0.11 \
        --port-name=inst2  # now corrected
---
:error: Vnet::Endpoints::Errors::DuplicateUUID
:message: if-inst2x
:code: '102'

tried again with corrected port-name, still get error because of the inserted record.