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/*
* 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.inject.*;
import com.google.inject.matcher.AbstractMatcher;
import com.google.inject.spi.Dependency;
import com.google.inject.spi.DependencyAndSource;
import com.google.inject.spi.HasDependencies;
import com.google.inject.spi.ProvisionListener;
import io.datakernel.eventloop.Eventloop;
import io.datakernel.eventloop.EventloopServer;
import io.datakernel.eventloop.EventloopService;
import io.datakernel.net.BlockingSocketServer;
import io.datakernel.util.Initializable;
import io.datakernel.util.Initializer;
import io.datakernel.util.guice.GuiceUtils;
import io.datakernel.util.guice.OptionalInitializer;
import io.datakernel.worker.Worker;
import io.datakernel.worker.WorkerPoolModule;
import io.datakernel.worker.WorkerPools;
import org.slf4j.Logger;
import javax.sql.DataSource;
import java.io.Closeable;
import java.util.*;
import java.util.concurrent.*;
import java.util.concurrent.atomic.AtomicInteger;
import java.util.concurrent.atomic.AtomicReference;
import static io.datakernel.service.ServiceAdapters.*;
import static io.datakernel.util.CollectionUtils.*;
import static io.datakernel.util.Preconditions.checkNotNull;
import static io.datakernel.util.Preconditions.checkState;
import static java.util.Collections.emptySet;
import static java.util.concurrent.CompletableFuture.completedFuture;
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.
*
* Consider some lifecycle details of this module:
*
* -
* Put all objects from the graph which can be treated as
* {@link Service} instances.
*
* -
* Starts services concurrently starting at leaf graph nodes (independent
* services) and ending with root nodes.
*
* -
* Stop services starting from root and ending with independent services.
*
*
*
* 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.
*
* An application terminates if a circular dependency found.
*/
public final class ServiceGraphModule extends AbstractModule implements Initializable {
private final Logger logger = getLogger(this.getClass());
private final Map, ServiceAdapter> registeredServiceAdapters = new LinkedHashMap<>();
private final Set> excludedKeys = new LinkedHashSet<>();
private final Map, ServiceAdapter> keys = new LinkedHashMap<>();
private final Map, Set>> addedDependencies = new HashMap<>();
private final Map, Set>> removedDependencies = new HashMap<>();
private final Set> singletonKeys = new HashSet<>();
private final Set> workerKeys = new HashSet<>();
private final Map, Set>> workerDependencies = new HashMap<>();
private final IdentityHashMap services = new IdentityHashMap<>();
private final Executor executor;
private ServiceGraph serviceGraph;
private Initializer initializer = Initializer.empty();
private ServiceGraphModule() {
this.executor = new ThreadPoolExecutor(0, Integer.MAX_VALUE,
10, TimeUnit.MILLISECONDS,
new SynchronousQueue<>());
}
/**
* 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, forService())
.register(BlockingService.class, forBlockingService())
.register(BlockingSocketServer.class, forBlockingSocketServer())
.register(Closeable.class, forCloseable())
.register(ExecutorService.class, forExecutorService())
.register(Timer.class, forTimer())
.register(DataSource.class, forDataSource())
.register(EventloopService.class, forEventloopService())
.register(EventloopServer.class, forEventloopServer())
.register(Eventloop.class, forEventloop());
}
public static ServiceGraphModule newInstance() {
return new ServiceGraphModule();
}
/**
* Puts an instance of class and its factory to the factoryMap
*
* @param 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 ServiceGraphModule register(Class type, ServiceAdapter 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 type of service
* @return ServiceGraphModule with change
*/
public ServiceGraphModule registerForSpecificKey(Key key, ServiceAdapter factory) {
keys.put(key, factory);
return this;
}
public ServiceGraphModule excludeSpecificKey(Key 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.computeIfAbsent(key, key1 -> new HashSet<>()).add(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.computeIfAbsent(key, key1 -> new HashSet<>()).add(keyDependency);
return this;
}
public ServiceGraphModule withInitializer(Initializer initializer) {
this.initializer = initializer;
return this;
}
private Service getWorkersServiceOrNull(Key key, List instances) {
List 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 CompletableFuture start() {
List> futures = new ArrayList<>();
for (Service service : services) {
futures.add(service != null ? service.start() : null);
}
return combineFutures(futures, Runnable::run);
}
@Override
public CompletableFuture stop() {
List> futures = new ArrayList<>();
for (Service service : services) {
futures.add(service != null ? service.stop() : null);
}
return combineFutures(futures, Runnable::run);
}
};
}
private static Throwable getRootCause(Throwable throwable) {
Throwable cause;
while ((cause = throwable.getCause()) != null) {
throwable = cause;
}
return throwable;
}
private static CompletableFuture combineFutures(List> futures, Executor executor) {
CompletableFuture resultFuture = new CompletableFuture<>();
AtomicInteger count = new AtomicInteger(futures.size());
AtomicReference exception = new AtomicReference<>();
for (CompletableFuture future : futures) {
CompletableFuture finalFuture = future != null ? future : completedFuture(null);
finalFuture.whenCompleteAsync((o, throwable) -> {
if (throwable != null) {
exception.set(getRootCause(throwable));
}
if (count.decrementAndGet() == 0) {
if (exception.get() != null) {
resultFuture.completeExceptionally(exception.get());
} else {
resultFuture.complete(null);
}
}
}, executor);
}
return resultFuture;
}
@SuppressWarnings("unchecked")
private Service getServiceOrNull(Key key, 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> foundRegisteredClasses = new ArrayList<>();
l1:
for (Map.Entry, ServiceAdapter> entry : registeredServiceAdapters.entrySet()) {
Class registeredClass = entry.getKey();
if (registeredClass.isAssignableFrom(instance.getClass())) {
Iterator> 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) {
ServiceAdapter finalServiceAdapter = serviceAdapter;
Service asyncService = new Service() {
@Override
public CompletableFuture start() {
return finalServiceAdapter.start(instance, executor);
}
@Override
public CompletableFuture stop() {
return finalServiceAdapter.stop(instance, executor);
}
};
service = new CachedService(asyncService);
services.put(instance, service);
return service;
}
return null;
}
private void createGuiceGraph(Injector injector, ServiceGraph graph) {
WorkerPools workerPools = injector.getInstance(WorkerPools.class);
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) {
Service service = getWorkersServiceOrNull(key, workerPools.getAllObjects(key));
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> dependencies = new HashSet<>();
for (Dependency dependency : ((HasDependencies) binding).getDependencies()) {
dependencies.add(dependency.getKey());
}
if (!difference(removedDependencies.getOrDefault(key, emptySet()), dependencies).isEmpty()) {
logger.warn("Unused removed dependencies for {} : {}", key, difference(removedDependencies.getOrDefault(key, emptySet()), dependencies));
}
if (!intersection(dependencies, addedDependencies.getOrDefault(key, emptySet())).isEmpty()) {
logger.warn("Unused added dependencies for {} : {}", key, intersection(dependencies, addedDependencies.getOrDefault(key, emptySet())));
}
for (Key dependencyKey : difference(union(union(dependencies, workerDependencies.getOrDefault(key, emptySet())),
addedDependencies.getOrDefault(key, emptySet())), removedDependencies.getOrDefault(key, emptySet()))) {
graph.add(key, dependencyKey);
}
}
@Override
protected void configure() {
install(new WorkerPoolModule());
bindListener(new AbstractMatcher>() {
@Override
public boolean matches(Binding binding) {
return WorkerPoolModule.isWorkerScope(binding);
}
}, new ProvisionListener() {
@Override
public void onProvision(ProvisionInvocation provision) {
synchronized (ServiceGraphModule.this) {
if (serviceGraph != null && serviceGraph.isStarted()) {
logger.error("Service graph already started, ignoring {}", provision.getBinding().getKey());
return;
}
if (provision.provision() != null) {
workerKeys.add(provision.getBinding().getKey());
}
List chain = provision.getDependencyChain();
if (chain.size() >= 2) {
Key key = chain.get(chain.size() - 2).getDependency().getKey();
Key dependencyKey = provision.getBinding().getKey();
if (key.getTypeLiteral().getRawType() != ServiceGraph.class) {
workerDependencies.computeIfAbsent(key, key1 -> new HashSet<>()).add(dependencyKey);
}
}
}
}
});
bindListener(new AbstractMatcher>() {
@Override
public boolean matches(Binding binding) {
return GuiceUtils.isSingleton(binding);
}
}, new ProvisionListener() {
@Override
public void onProvision(ProvisionInvocation provision) {
synchronized (ServiceGraphModule.this) {
if (serviceGraph != null && serviceGraph.isStarted()) {
logger.error("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
@Singleton
synchronized ServiceGraph serviceGraph(Injector injector,
OptionalInitializer serviceGraphModuleOptionalInitializer,
OptionalInitializer serviceGraphOptionalInitializer) {
serviceGraphModuleOptionalInitializer.accept(this);
if (serviceGraph == null) {
serviceGraph = ServiceGraph.create()
.withStartCallback(() -> {
createGuiceGraph(injector, serviceGraph);
serviceGraph.removeIntermediateNodes();
})
.withNodeSuffixes(key -> {
List list = injector.getInstance(WorkerPools.class).getAllObjects(key);
return list.isEmpty() ? null : list.size();
})
.initialize(initializer)
.initialize(serviceGraphOptionalInitializer);
}
return serviceGraph;
}
private class CachedService implements Service {
private final Service service;
private CompletableFuture startFuture;
private CompletableFuture stopFuture;
private CachedService(Service service) {
this.service = service;
}
@Override
synchronized public CompletableFuture start() {
checkState(stopFuture == null);
if (startFuture == null) {
startFuture = service.start();
}
return startFuture;
}
@Override
synchronized public CompletableFuture stop() {
checkState(startFuture != null);
if (stopFuture == null) {
stopFuture = service.stop();
}
return stopFuture;
}
}
}