Hands-On Software Engineering with Golang

Creating a distributed barrier for the graph execution steps

A barrier can be thought of as a rendezvous point for a set of processes. Once a process enters the barrier, it is prevented from making any progress until all other expected processes also enter the barrier.

In Go, we could model a barrier with the help of the sync.WaitGroup primitive, as follows:

func barrier(numWorkers int) {    var wg sync.WaitGroup    wg.Add(numWorkers)    for i := 0; i < numWorkers; i++ {        go func() {            wg.Done()            fmt.Printf("Entered the barrier; waiting for other goroutines to join")            wg.Wait()            fmt.Printf("Exited the barrier")        }()    }    wg.Wait()}

To guarantee that each worker executes the various stages of the graph state machine in lock-step with the other workers, we must ...