/*
* Copyright (C) 2015 SoftIndex LLC.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package io.datakernel.service;
import com.google.common.base.Throwables;
import com.google.common.collect.HashMultimap;
import com.google.common.collect.SetMultimap;
import com.google.common.util.concurrent.Futures;
import com.google.common.util.concurrent.ListenableFuture;
import com.google.common.util.concurrent.SettableFuture;
import com.google.inject.*;
import com.google.inject.matcher.AbstractMatcher;
import com.google.inject.spi.*;
import io.datakernel.eventloop.Eventloop;
import io.datakernel.eventloop.EventloopServer;
import io.datakernel.eventloop.EventloopService;
import io.datakernel.net.BlockingSocketServer;
import io.datakernel.worker.Worker;
import io.datakernel.worker.WorkerPoolModule;
import io.datakernel.worker.WorkerPoolObjects;
import org.slf4j.Logger;
import javax.sql.DataSource;
import java.io.Closeable;
import java.lang.annotation.Annotation;
import java.lang.reflect.Method;
import java.util.*;
import java.util.concurrent.*;
import java.util.concurrent.atomic.AtomicInteger;
import java.util.concurrent.atomic.AtomicReference;
import static com.google.common.base.Preconditions.checkNotNull;
import static com.google.common.base.Preconditions.checkState;
import static com.google.common.collect.Sets.*;
import static com.google.common.util.concurrent.MoreExecutors.directExecutor;
import static org.slf4j.LoggerFactory.getLogger;
/**
* Builds dependency graph of {@code Service} objects based on Guice's object
* graph. Service graph module is capable to start services concurrently.
* <p>
* Consider some lifecycle details of this module:
* <ul>
* <li>
* Put all objects from the graph which can be treated as
* {@link Service} instances.
* </li>
* <li>
* Starts services concurrently starting at leaf graph nodes (independent
* services) and ending with root nodes.
* </li>
* <li>
* Stop services starting from root and ending with independent services.
* </li>
* </ul>
* <p>
* An ability to use {@link ServiceAdapter} objects allows to create a service
* from any object by providing it's {@link ServiceAdapter} and registering
* it in {@code ServiceGraphModule}. Take a look at {@link ServiceAdapters},
* which has a lot of implemented adapters. Its necessarily to annotate your
* object provider with {@link Worker @Worker} or {@link Singleton @Singleton}
* annotation.
* <p>
* An application terminates if a circular dependency found.
*/
public final class ServiceGraphModule extends AbstractModule {
private final Logger logger = getLogger(this.getClass());
private final Map<Class<?>, ServiceAdapter<?>> registeredServiceAdapters = new LinkedHashMap<>();
private final Set<Key<?>> excludedKeys = new LinkedHashSet<>();
private final Map<Key<?>, ServiceAdapter<?>> keys = new LinkedHashMap<>();
private final SetMultimap<Key<?>, Key<?>> addedDependencies = HashMultimap.create();
private final SetMultimap<Key<?>, Key<?>> removedDependencies = HashMultimap.create();
private final Set<Key<?>> singletonKeys = new HashSet<>();
private final Set<Key<?>> workerKeys = new HashSet<>();
private final SetMultimap<Key<?>, Key<?>> workerDependencies = HashMultimap.create();
private final IdentityHashMap<Object, CachedService> services = new IdentityHashMap<>();
private final Executor executor;
private WorkerPoolModule workerPoolModule;
private ServiceGraph serviceGraph;
private ServiceGraphModule() {
this.executor = new ThreadPoolExecutor(0, Integer.MAX_VALUE,
10, TimeUnit.MILLISECONDS,
new SynchronousQueue<Runnable>());
}
/**
* Creates a service graph with default configuration, which is able to
* handle {@code Service, BlockingService, Closeable, ExecutorService,
* Timer, DataSource, EventloopService, EventloopServer} and
* {@code Eventloop} as services.
*
* @return default service graph
*/
public static ServiceGraphModule defaultInstance() {
return newInstance()
.register(Service.class, ServiceAdapters.forService())
.register(BlockingService.class, ServiceAdapters.forBlockingService())
.register(BlockingSocketServer.class, ServiceAdapters.forBlockingSocketServer())
.register(Closeable.class, ServiceAdapters.forCloseable())
.register(ExecutorService.class, ServiceAdapters.forExecutorService())
.register(Timer.class, ServiceAdapters.forTimer())
.register(DataSource.class, ServiceAdapters.forDataSource())
.register(EventloopService.class, ServiceAdapters.forEventloopService())
.register(EventloopServer.class, ServiceAdapters.forEventloopServer())
.register(Eventloop.class, ServiceAdapters.forEventloop());
}
public static ServiceGraphModule newInstance() {
return new ServiceGraphModule();
}
private static boolean isSingleton(Binding<?> binding) {
return binding.acceptScopingVisitor(new BindingScopingVisitor<Boolean>() {
@Override
public Boolean visitNoScoping() {
return false;
}
@Override
public Boolean visitScopeAnnotation(Class<? extends Annotation> visitedAnnotation) {
return visitedAnnotation.equals(Singleton.class);
}
@Override
public Boolean visitScope(Scope visitedScope) {
return visitedScope.equals(Scopes.SINGLETON);
}
@Override
public Boolean visitEagerSingleton() {
return true;
}
});
}
private static String prettyPrintAnnotation(Annotation annotation) {
StringBuilder sb = new StringBuilder();
Method[] methods = annotation.annotationType().getDeclaredMethods();
boolean first = true;
if (methods.length != 0) {
for (Method m : methods) {
try {
Object value = m.invoke(annotation);
if (value.equals(m.getDefaultValue()))
continue;
String valueStr = (value instanceof String ? "\"" + value + "\"" : value.toString());
String methodName = m.getName();
if ("value".equals(methodName) && first) {
sb.append(valueStr);
first = false;
} else {
sb.append(first ? "" : ",").append(methodName).append("=").append(valueStr);
first = false;
}
} catch (ReflectiveOperationException ignored) {
}
}
}
String simpleName = annotation.annotationType().getSimpleName();
return "@" + ("NamedImpl".equals(simpleName) ? "Named" : simpleName) + (first ? "" : "(" + sb + ")");
}
/**
* Puts an instance of class and its factory to the factoryMap
*
* @param <T> type of service
* @param type key with which the specified factory is to be associated
* @param factory value to be associated with the specified type
* @return ServiceGraphModule with change
*/
public <T> ServiceGraphModule register(Class<? extends T> type, ServiceAdapter<T> factory) {
registeredServiceAdapters.put(type, factory);
return this;
}
/**
* Puts the key and its factory to the keys
*
* @param key key with which the specified factory is to be associated
* @param factory value to be associated with the specified key
* @param <T> type of service
* @return ServiceGraphModule with change
*/
public <T> ServiceGraphModule registerForSpecificKey(Key<T> key, ServiceAdapter<T> factory) {
keys.put(key, factory);
return this;
}
public <T> ServiceGraphModule excludeSpecificKey(Key<T> key) {
excludedKeys.add(key);
return this;
}
/**
* Adds the dependency for key
*
* @param key key for adding dependency
* @param keyDependency key of dependency
* @return ServiceGraphModule with change
*/
public ServiceGraphModule addDependency(Key<?> key, Key<?> keyDependency) {
addedDependencies.put(key, keyDependency);
return this;
}
/**
* Removes the dependency
*
* @param key key for removing dependency
* @param keyDependency key of dependency
* @return ServiceGraphModule with change
*/
public ServiceGraphModule removeDependency(Key<?> key, Key<?> keyDependency) {
removedDependencies.put(key, keyDependency);
return this;
}
private Service getWorkersServiceOrNull(final Key<?> key, final List<?> instances) {
final List<Service> services = new ArrayList<>();
boolean found = false;
for (Object instance : instances) {
Service service = getServiceOrNull(key, instance);
services.add(service);
if (service != null) {
found = true;
}
}
if (!found)
return null;
return new Service() {
@Override
public ListenableFuture<?> start() {
List<ListenableFuture<?>> futures = new ArrayList<>();
for (Service service : services) {
futures.add(service != null ? service.start() : null);
}
return combineFutures(futures, directExecutor());
}
@Override
public ListenableFuture<?> stop() {
List<ListenableFuture<?>> futures = new ArrayList<>();
for (Service service : services) {
futures.add(service != null ? service.stop() : null);
}
return combineFutures(futures, directExecutor());
}
};
}
private static ListenableFuture<?> combineFutures(List<ListenableFuture<?>> futures, final Executor executor) {
final SettableFuture<?> resultFuture = SettableFuture.create();
final AtomicInteger count = new AtomicInteger(futures.size());
final AtomicReference<Throwable> exception = new AtomicReference<>();
for (ListenableFuture<?> future : futures) {
final ListenableFuture<?> finalFuture = future != null ? future : Futures.immediateFuture(null);
finalFuture.addListener(new Runnable() {
@Override
public void run() {
try {
finalFuture.get();
} catch (InterruptedException | ExecutionException e) {
exception.set(Throwables.getRootCause(e));
}
if (count.decrementAndGet() == 0) {
if (exception.get() != null)
resultFuture.setException(exception.get());
else
resultFuture.set(null);
}
}
}, executor);
}
return resultFuture;
}
@SuppressWarnings("unchecked")
private Service getServiceOrNull(Key<?> key, final Object instance) {
checkNotNull(instance);
CachedService service = services.get(instance);
if (service != null) {
return service;
}
if (excludedKeys.contains(key)) {
return null;
}
ServiceAdapter<?> serviceAdapter = keys.get(key);
if (serviceAdapter == null) {
List<Class<?>> foundRegisteredClasses = new ArrayList<>();
l1:
for (Map.Entry<Class<?>, ServiceAdapter<?>> entry : registeredServiceAdapters.entrySet()) {
Class<?> registeredClass = entry.getKey();
if (registeredClass.isAssignableFrom(instance.getClass())) {
Iterator<Class<?>> iterator = foundRegisteredClasses.iterator();
while (iterator.hasNext()) {
Class<?> foundRegisteredClass = iterator.next();
if (registeredClass.isAssignableFrom(foundRegisteredClass))
continue l1;
if (foundRegisteredClass.isAssignableFrom(registeredClass))
iterator.remove();
}
foundRegisteredClasses.add(registeredClass);
}
}
if (foundRegisteredClasses.size() == 1) {
serviceAdapter = registeredServiceAdapters.get(foundRegisteredClasses.get(0));
}
if (foundRegisteredClasses.size() > 1) {
throw new IllegalArgumentException("Ambiguous services found for " + instance.getClass() +
" : " + foundRegisteredClasses + ". Use register() methods to specify service.");
}
}
if (serviceAdapter != null) {
final ServiceAdapter finalServiceAdapter = serviceAdapter;
Service asyncService = new Service() {
@Override
public ListenableFuture<?> start() {
return finalServiceAdapter.start(instance, executor);
}
@Override
public ListenableFuture<?> stop() {
return finalServiceAdapter.stop(instance, executor);
}
};
service = new CachedService(asyncService);
services.put(instance, service);
return service;
}
return null;
}
private void createGuiceGraph(final Injector injector, final ServiceGraph graph) {
if (!difference(keys.keySet(), injector.getAllBindings().keySet()).isEmpty()) {
logger.warn("Unused services : {}", difference(keys.keySet(), injector.getAllBindings().keySet()));
}
for (Key<?> key : singletonKeys) {
Object instance = injector.getInstance(key);
Service service = getServiceOrNull(key, instance);
graph.add(key, service);
}
for (Key<?> key : workerKeys) {
WorkerPoolObjects poolObjects = workerPoolModule.getPoolObjects(key);
Service service = getWorkersServiceOrNull(key, poolObjects.getObjects());
graph.add(key, service);
}
for (Binding<?> binding : injector.getAllBindings().values()) {
processDependencies(binding.getKey(), injector, graph);
}
}
private void processDependencies(Key<?> key, Injector injector, ServiceGraph graph) {
Binding<?> binding = injector.getBinding(key);
if (!(binding instanceof HasDependencies))
return;
Set<Key<?>> dependencies = new HashSet<>();
for (Dependency<?> dependency : ((HasDependencies) binding).getDependencies()) {
dependencies.add(dependency.getKey());
}
if (!difference(removedDependencies.get(key), dependencies).isEmpty()) {
logger.warn("Unused removed dependencies for {} : {}", key, difference(removedDependencies.get(key), dependencies));
}
if (!intersection(dependencies, addedDependencies.get(key)).isEmpty()) {
logger.warn("Unused added dependencies for {} : {}", key, intersection(dependencies, addedDependencies.get(key)));
}
for (Key<?> dependencyKey : difference(union(union(dependencies, workerDependencies.get(key)),
addedDependencies.get(key)), removedDependencies.get(key))) {
graph.add(key, dependencyKey);
}
}
@Override
protected void configure() {
workerPoolModule = new WorkerPoolModule();
install(workerPoolModule);
bindListener(new AbstractMatcher<Binding<?>>() {
@Override
public boolean matches(Binding<?> binding) {
return WorkerPoolModule.isWorkerScope(binding);
}
}, new ProvisionListener() {
@Override
public <T> void onProvision(ProvisionInvocation<T> provision) {
synchronized (ServiceGraphModule.this) {
if (serviceGraph != null) {
logger.warn("Service graph already started, ignoring {}", provision.getBinding().getKey());
return;
}
if (provision.provision() != null) {
workerKeys.add(provision.getBinding().getKey());
}
List<DependencyAndSource> chain = provision.getDependencyChain();
if (chain.size() >= 2) {
Key<?> key = chain.get(chain.size() - 2).getDependency().getKey();
Key<T> dependencyKey = provision.getBinding().getKey();
if (key.getTypeLiteral().getRawType() != ServiceGraph.class) {
workerDependencies.put(key, dependencyKey);
}
}
}
}
});
bindListener(new AbstractMatcher<Binding<?>>() {
@Override
public boolean matches(Binding<?> binding) {
return isSingleton(binding);
}
}, new ProvisionListener() {
@Override
public <T> void onProvision(ProvisionInvocation<T> provision) {
synchronized (ServiceGraphModule.this) {
if (serviceGraph != null) {
logger.warn("Service graph already started, ignoring {}", provision.getBinding().getKey());
return;
}
if (provision.provision() != null) {
singletonKeys.add(provision.getBinding().getKey());
}
}
}
});
}
/**
* Creates the new {@code ServiceGraph} without circular dependencies and
* intermediary nodes
*
* @param injector injector for building the graphs of objects
* @return created ServiceGraph
*/
@Provides
synchronized ServiceGraph serviceGraph(final Injector injector) {
if (serviceGraph == null) {
serviceGraph = new ServiceGraph() {
@Override
protected String nodeToString(Object node) {
Key<?> key = (Key<?>) node;
Annotation annotation = key.getAnnotation();
WorkerPoolObjects poolObjects = workerPoolModule.getPoolObjects(key);
return key.getTypeLiteral() +
(annotation != null ? " " + prettyPrintAnnotation(annotation) : "") +
(poolObjects != null ? " [" + poolObjects.getWorkerPool().getWorkersCount() + "]" : "");
}
};
createGuiceGraph(injector, serviceGraph);
serviceGraph.removeIntermediateNodes();
logger.info("Services graph: \n" + serviceGraph);
}
return serviceGraph;
}
private class CachedService implements Service {
private final Service service;
private ListenableFuture<?> startFuture;
private ListenableFuture<?> stopFuture;
private CachedService(Service service) {
this.service = service;
}
@Override
synchronized public ListenableFuture<?> start() {
checkState(stopFuture == null);
if (startFuture == null) {
startFuture = service.start();
}
return startFuture;
}
@Override
synchronized public ListenableFuture<?> stop() {
checkState(startFuture != null);
if (stopFuture == null) {
stopFuture = service.stop();
}
return stopFuture;
}
}
}