Delay in Receiving CANCEL from INVITE Transaction After Recent Updates

[moksh-samespace]

After updating to the latest version, I've noticed a significant delay in receiving a CANCEL message from an INVITE transaction. This was not the case with the previous version. Below is a snippet of the code where the issue is being observed:

for {
    select {
    case <-tx.Acks():
        fmt.Println("Ack received")
    case <-tx.Done():
        fmt.Println("Transaction done", tx.Err() == sip.ErrTransactionCanceled)
        // Signal transaction is done.
        // Check any errors with tx.Err() to have more info why terminated
        return
    }
}

[emiago]

Hi @moksh-samespace . There is UDP termination timer. This library follows some extensions RFC.
You can check your state transitions with sip.TransactionDebug and debug logging

[moksh-samespace]

Yes, I can see the debug log. However, I need to access the 'done' event immediately as I need to take action based on it. How can I achieve this?

Log:

{"level":"debug","caller":"transactionLayer","key":"z9hG4bK-524287-1---c0e4633ad76b1c5f__127.0.0.1__50502__INVITE","input":"server_input_user_1xx","state":"inviteStateProcceeding-fm","time":"2025-02-25T11:06:43+05:30","message":"Changing transaction state"}
{"level":"debug","caller":"transactionLayer","key":"z9hG4bK-524287-1---c0e4633ad76b1c5f__127.0.0.1__50502__INVITE","input":"server_input_cancel","state":"inviteStateProcceeding-fm","time":"2025-02-25T11:06:47+05:30","message":"Changing transaction state"}
{"level":"debug","caller":"transactionLayer","time":"2025-02-25T11:06:47+05:30","message":"Passing 487 on CANCEL"}
{"level":"debug","caller":"transactionLayer","key":"z9hG4bK-524287-1---c0e4633ad76b1c5f__127.0.0.1__50502__INVITE","input":"server_input_user_300_plus","state":"inviteStateProcceeding-fm","time":"2025-02-25T11:06:47+05:30","message":"Changing transaction state"}
{"level":"debug","caller":"transactionLayer","key":"z9hG4bK-524287-1---c0e4633ad76b1c5f__127.0.0.1__50502__INVITE","input":"server_input_ack","state":"inviteStateCompleted-fm","time":"2025-02-25T11:06:47+05:30","message":"Changing transaction state"}

[emiago]

Cancelation is something still open thing, but essentially I see this will need some hook.
Now as some other approach, you have to check error, on every ACK from tx.Acks() or zero out that sip timer. Timer_H I think.

For better behavior, cancelation hook or something similar will be added. Had no time to look on this.
We had this in past, but it caused more issues

[moksh-samespace]

I see, thanks for the update. I will work around timers for now.

[emiago]

Added OnCancel hook on main branch.
This also now fixes issue of delayed dialog Context termination.