@Test
public void testStateTransition()
throws InterruptedException, ExecutionException, TimeoutException {
InMemoryZKServer zkServer = InMemoryZKServer.builder().build();
zkServer.startAndWait();
try {
final String namespace =
Joiner.on('/').join("/twill", RunIds.generate(), "runnables", "Runner1");
final ZKClientService zkClient =
ZKClientService.Builder.of(zkServer.getConnectionStr()).build();
zkClient.startAndWait();
zkClient.create(namespace, null, CreateMode.PERSISTENT).get();
try {
JsonObject content = new JsonObject();
content.addProperty("containerId", "container-123");
content.addProperty("host", "localhost");
RunId runId = RunIds.generate();
final Semaphore semaphore = new Semaphore(0);
ZKServiceDecorator service =
new ZKServiceDecorator(
ZKClients.namespace(zkClient, namespace),
runId,
Suppliers.ofInstance(content),
new AbstractIdleService() {
@Override
protected void startUp() throws Exception {
Preconditions.checkArgument(
semaphore.tryAcquire(5, TimeUnit.SECONDS), "Fail to start");
}
@Override
protected void shutDown() throws Exception {
Preconditions.checkArgument(
semaphore.tryAcquire(5, TimeUnit.SECONDS), "Fail to stop");
}
});
final String runnablePath = namespace + "/" + runId.getId();
final AtomicReference<String> stateMatch = new AtomicReference<String>("STARTING");
watchDataChange(zkClient, runnablePath + "/state", semaphore, stateMatch);
Assert.assertEquals(Service.State.RUNNING, service.start().get(5, TimeUnit.SECONDS));
stateMatch.set("STOPPING");
Assert.assertEquals(Service.State.TERMINATED, service.stop().get(5, TimeUnit.SECONDS));
} finally {
zkClient.stopAndWait();
}
} finally {
zkServer.stopAndWait();
}
}
private void watchDataChange(
final ZKClientService zkClient,
final String path,
final Semaphore semaphore,
final AtomicReference<String> stateMatch) {
Futures.addCallback(
zkClient.getData(
path,
new Watcher() {
@Override
public void process(WatchedEvent event) {
if (event.getType() == Event.EventType.NodeDataChanged) {
watchDataChange(zkClient, path, semaphore, stateMatch);
}
}
}),
new FutureCallback<NodeData>() {
@Override
public void onSuccess(NodeData result) {
String content = new String(result.getData(), Charsets.UTF_8);
JsonObject json = new Gson().fromJson(content, JsonElement.class).getAsJsonObject();
if (stateMatch.get().equals(json.get("state").getAsString())) {
semaphore.release();
}
}
@Override
public void onFailure(Throwable t) {
exists();
}
private void exists() {
Futures.addCallback(
zkClient.exists(
path,
new Watcher() {
@Override
public void process(WatchedEvent event) {
if (event.getType() == Event.EventType.NodeCreated) {
watchDataChange(zkClient, path, semaphore, stateMatch);
}
}
}),
new FutureCallback<Stat>() {
@Override
public void onSuccess(Stat result) {
if (result != null) {
watchDataChange(zkClient, path, semaphore, stateMatch);
}
}
@Override
public void onFailure(Throwable t) {
LOG.error(t.getMessage(), t);
}
});
}
});
}