[MultiDB] SonicV2Connector class use DBInterface class as member instead of inheritance

[dzhangalibaba]

• issue : Exception seen when trying to connect and database service is not responding #72

• the root cause is : SonicV2Connector connect(dbname) calls base class method connect(dbid), while when connection failed and retry, base class try to call self. connect() which is onicV2Connector connect(dbname) since name are the same. It should call its own connect(dbid).

• for multiDB, we use methods from SonicV2Connector instead of DBInterface based on earlier changes

• we should make sure DBInterface class method uses its own methods inside, hence making DBInterface class as a member of SonicV2Connector instead of inheritance

Signed-off-by: Dong Zhang [email protected]

[dzhangalibaba]

@rajendra-dendukuri @qiluo-msft Please help review

[dzhangalibaba]

Test

When stop all dockers , retry connect until database is restarted and set/get works fine

admin@ASW-7005:~$ cat /etc/sonic/testdb.py 
#!/usr/bin/env python2.7
from swsssdk import SonicV2Connector

db = SonicV2Connector()
db.connect(db.CONFIG_DB,True)

db.set("CONFIG_DB", "hashhash", "kk", "vv")
print(db.get_all("CONFIG_DB", "hashhash"))
admin@ASW-7005:~$ /etc/sonic/testdb.py 
{'kk': 'vv'}
admin@ASW-7005:~$ 


admin@ASW-7005:~$ docker stop $(docker ps -aq)
edfd0e02be03
b1a76602159b
f16090b43b43
9b67c63b2c8f
bb2f217daea0
4026b5e72382
c090c9da180c
7ddce00e4387
23df59d0f92b
a7fc3d31a590
4d142775e9b3
5ee83628e713
48a5d88bdf5e
725d3b951e66
admin@ASW-7005:~$ /etc/sonic/testdb.py 
{'kk': 'vv'}
admin@ASW-7005:~$ 

[qiluo-msft]

_connect [](start = 13, length = 8)

We need to fix SonicV2Connector. There is nothing wrong in DBInterface

[dzhangalibaba]

use composition instead and only change SonicV2Connector wrapper.

[qiluo-msft]

class SonicV2Connector(DBInterface):

Could it use composition instead of inheritance? #Closed

---

Refers to: src/swsssdk/dbconnector.py:226 in 4391266. [](commit_id = 4391266, deletion_comment = False)

[dzhangalibaba]

class SonicV2Connector(DBInterface):

Could it use composition instead of inheritance?

Refers to: src/swsssdk/dbconnector.py:226 in ac457fb. [](commit_id = ac457fb, deletion_comment = False)

yes we can use it. Updated

[qiluo-msft]

[rajendra-dendukuri]

Verified the patch and it looks good.

[SuvarnaMeenakshi]

@qiluo-msft , @dzhangalibaba is there a plan to merge this to 201911 branch?

[qiluo-msft]

Yes. Added the label.