service-bus (Java)

service-bus sits on top of seda-bus: seda-bus moves envelopes between named channels and walks their routing slips; service-bus gives you services as the unit of composition — register them, start/stop/pause them, let them find each other, and watch their health.

Each service becomes one seda-bus channel keyed by its class name, with the service as that channel's consumer. A service orchestrates others by pushing routes onto the envelope's DynamicRoutingSlip; the bus does the rest.

Dependencies: resolvingarchitecture:common and resolvingarchitecture:seda-bus.

ServiceBus bus = new ServiceBus(properties);
bus.start(properties);

bus.registerAndStartServices(IdentityService.class, RoutingService.class);
bus.awaitRunning(5_000, IdentityService.class, RoutingService.class);

// discovery
RoutingService router = bus.getService(RoutingService.class);
List<ProtocolService> transports = bus.findRunningServices(ProtocolService.class);

// send
Envelope e = Envelope.documentFactory();
e.addRoute(RoutingService.class, "ROUTE");
e.ratchet();
bus.send(e);                         // fire and forget
bus.send(e, reply -> { /* ... */ }); // with an end-of-slip callback

bus.gracefulShutdown();

public class MyDaemon extends ra.servicebus.Daemon {
    public static void main(String[] args) { new MyDaemon().launch(args); }

    protected String configName() { return "my.config"; }
    protected void beforeStart(Properties config) { /* dirs, logging, time zone */ }
    protected void onBusStarted(ServiceBus bus, Properties config) {
        bus.registerAndStartServices(FooService.class, BarService.class);
    }
}

launch loads config, runs the hooks, installs a shutdown hook, and idles until the bus stops.

The String-based registerService(...) overloads remain for the ServiceRegistrar contract and ControlCommand handling.

• Dependency-ordered registration — a service's getServicesDependentUpon() entries are registered first.
• Async start — startService returns immediately; the service starts on its own thread. Use awaitRunning to join.
• UNSTABLE auto-restart — a service reporting ServiceStatus.UNSTABLE is restarted on a background thread.
• Dead letters — deadLetter(Envelope) appends JSON (one per line) to <baseDir>/deadLetter.json, rotating past 5 MB, keeping 5 files.
• Graceful shutdown stops each service on its own thread and waits up to 30 s (5 s for a hard shutdown()), then stops the bus.

mvn test        # needs common:1.2.0 and seda-bus:1.3.1 in the local repo
mvn package

• DESIGN.md — the model and the seams
• TODO.md — what's next
• CHANGELOG.md