Skip to main content

Start and stop a process

A worker with no processes is just a heartbeat. Processes are the things you actually start and stop.

Declare one​

@SynapsysProcess(name = "nightly-sync", type = ENDLESS)
public class NightlySync extends AbstractSynapsysProcess {

    @Override
    public void run(StopSignal stop) {
        while (!stop.requested()) {
            reconcileInvoices();
            stop.sleep(Duration.ofMinutes(5));
        }
    }
}

Two things are doing work here:

  • type = ENDLESS — this process runs until told to stop. The alternative is PROGRESSIVE, which runs to completion on its own.
  • stop.requested() — stopping is cooperative. The Core asks; your loop decides when it is safe to leave. A process that never checks the signal cannot be stopped.

Drive it​

Restart the application. nightly-sync now appears under the worker in the console, in state idle.

Press Start. Within one heartbeat the state becomes running.

Press Stop. The state becomes stopping first, then idle once your loop has actually returned — not before. That intermediate state is the honest one: it means the Core has asked and is waiting.

What just happened​

The console did not call your application. It could not — your application has no open port. It wrote a desired state into the Core's database, and your worker picked it up on its next heartbeat.

That indirection is the whole design. Read the heartbeat protocol for how it avoids applying the same command twice.