How to use maapi_request_action_th

CDB and CDB API
1

Hi,

Can anyone please tell me how can we use below function to use transaction in action callpoint.

int maapi_request_action_th(int sock, int thandle, confd_tag_value_t
*params, int nparams, confd_tag_value_t **values, int *nvalues, const
char *fmt, …);

Regards,
Anup Agrawal

2

Hi,

maapi_request_action_th() is used to invoke an action. It is not normally used from an action callpoint that was called because an action was invoked.

See the confd_lib_dp(3) man page for details.

3

Hi cohult,

thanks for the response.
If i want to start the write transaction from action callpoint which steps i need to follow. Because, when i am trying to start normal CDB_RUNNING session, Confd getting stuck on apply_transaction function.

Below process i followed to start transaction from action callpoint,
/* Session creation */
CDA_CONFD_FATAL(CDA_maapi_start(CDB_RUNNING, &th, IMMEDIATE));
CDA_maapi_set_namespace(th, core_model__ns);

     maapi_ret = CDA_maapi_exists(th, CORE_MODEL_FD_FC, vlanFd_uuid, vlanFc_uuid);

     if(CONFD_TRUE != maapi_ret)
     {
         CDA_CONFD_FATAL(CDA_maapi_create(th, CORE_MODEL_FD_FC, vlanFd_uuid, vlanFc_uuid));
         CDA_CONFD_FATAL(CDA_maapi_cd(th, CORE_MODEL_FD_FC, vlanFd_uuid, vlanFc_uuid));

         /* set the vlan-fc local id */
         CDA_SET_STR(&vt, vlanFc_localId);
         CDA_CONFD_FATAL(CDA_maapi_set_elem(th, &vt, CORE_MODEL_LOCAL_ID_ENT));

     }
     else
     {
         printf("RPC instance for given vlan ID already exists");
     }

     CDA_CONFD_FATAL(CDA_maapi_apply_trans(th));
     CDA_CONFD_FATAL(CDA_maapi_end(th));

Regards,
Anup

4

Hi,

Start a separate thread/process that perform the transaction if your action handler thread also handle subscriptions or other callpoints triggered by the commit (apply).

Regards

5

Hi Cohult,

What if the action handler is expected to reply a value based on DB commit success.

As pee the above suggestion , it is expected to open a separate thread to perform commit (the configuration)

Please share further inputs.

Regards,
Chandra

6

hi All,

Can anyone help on the above query?

I tried to use confd_cmd tool from action handler (as it will work like a new process), again it halts at MAAPI_APPLY_TRANS

Below are confd_cmd trace logs
TRACE Connected (maapi) to ConfD
TRACE MAAPI_START_USER_SESSION → CONFD_OK
TRACE MAAPI_START_TRANS → CONFD_OK
TRACE MAAPI_CREATE /temp/container-1/list{60} → CONFD_OK
TRACE MAAPI_SET_ELEM2 /temp/container-1/list{60}/Rowstatus → CONFD_OK
TRACE MAAPI_APPLY_TRANS

Regards,
Chandrakanth S.

7

There is likely a deadlock. ConfD is waiting for your thread to reply to for example a transaction subscription notification or some other callback invocation inside the transaction lock, while you are starting a transaction that will wait for that transaction to finish before continuing.

8

hi Cohult,

Thanks for the reply
Can you please help on comment 4/7 ?

Regards,
Chandrakanth S.

9

I suggest looking into the ConfD developer log (log level trace) which will tell what the ConfD transaction manager is doing at the time of the MAAPI apply.