Threading Redis connection in C++

I was wondering how to implement Redis NOSQL calls into the the C++ Std Threading library code from the C++ Concurrency in Action book.

I am using the Github repo https://github.com/subjam/concurrency-in-action

source file of
https://github.com/subjam/concurrency-in-action/blob/master/ch7/stack.cpp

I was wondering if I placed my Redis NOSQL connection code in the push() function is wise.

I am also using Redox which is a C++ wrapper which includes the Hiredis C library.

https://github.com/hmartiro/redox

I am using the subscriber NOSQL pattern which would be included in the Threading push() function. This would make the connection and query executed each time there is a push but no semaphore/mutex would be needed (I assume). At line 145 of push() in stack.cpp, can I rewrite the push function as?

void push(stack<int>* s)
{
    Redox rdx; Subscriber sub;
    if(!rdx.connect() || !sub.connect()) return;

    sub.subscribe("hello", [](const string& topic, const string& msg) {
          …parse msg fields into data structure …
    s->push(data);  

   });
}

Or should I make the the following connection code once before executing the push() function?

Redox rdx; Subscriber sub;
if(!rdx.connect() || !sub.connect()) return ;

Would there be a threading conflict if I keep the Redis connection code outside of the push()
Or is there a more optimal way of coding this within stack.cpp? Thanks