/**
* Copyright (C) 2010-2017 Structr GmbH
*
* This file is part of Structr <http://structr.org>.
*
* Structr is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as
* published by the Free Software Foundation, either version 3 of the
* License, or (at your option) any later version.
*
* Structr is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with Structr. If not, see <http://www.gnu.org/licenses/>.
*/
package org.structr.agent;
import java.util.Collection;
import java.util.Collections;
import java.util.LinkedHashSet;
import java.util.LinkedList;
import java.util.List;
import java.util.Map;
import java.util.Map.Entry;
import java.util.Queue;
import java.util.Set;
import java.util.concurrent.ConcurrentHashMap;
import java.util.concurrent.ConcurrentLinkedQueue;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.structr.api.service.Command;
import org.structr.api.service.RunnableService;
import org.structr.api.service.StructrServices;
import org.structr.core.Services;
import org.structr.schema.ConfigurationProvider;
//~--- classes ----------------------------------------------------------------
/**
* The agent service main class.
*
*
*/
public class AgentService extends Thread implements RunnableService {
private static final Logger logger = LoggerFactory.getLogger(AgentService.class.getName());
//~--- fields ---------------------------------------------------------
private final int maxAgents = 4; // TODO: make configurable
private final Map<String, List<Agent>> runningAgents = new ConcurrentHashMap<>(10, 0.9f, 8);
private final Map<String, Class> agentClassCache = new ConcurrentHashMap<>(10, 0.9f, 8);
private final Queue<Task> taskQueue = new ConcurrentLinkedQueue<>();
private Set<Class> supportedCommands = null;
private boolean run = false;
//~--- constructors ---------------------------------------------------
public AgentService() {
super("AgentService");
supportedCommands = new LinkedHashSet<>();
supportedCommands.add(ProcessTaskCommand.class);
super.setDaemon(true);
}
//~--- methods --------------------------------------------------------
public void processTask(Task task) {
synchronized (taskQueue) {
taskQueue.add(task);
logger.debug("Task {} added to task queue", task);
}
}
public Agent findAgentForTask(Task task) {
List<Agent> agents = getRunningAgentsForTask(task.getClass());
synchronized (agents) {
for (Agent agent : agents) {
if (agent.getTaskQueue().contains(task)) {
return (agent);
}
}
}
return (null);
}
@Override
public void run() {
logger.info("AgentService started");
while (run) {
Task nextTask = taskQueue.poll();
if (nextTask != null) {
assignNextAgentForTask(nextTask);
}
// let others act
try { Thread.sleep(10); } catch(Throwable ignore) {}
}
}
public void notifyAgentStart(Agent agent) {
List<Agent> agents = getRunningAgentsForTask(agent.getSupportedTaskType());
synchronized (agents) {
agents.add(agent);
}
}
public void notifyAgentStop(Agent agent) {
List<Agent> agents = getRunningAgentsForTask(agent.getSupportedTaskType());
synchronized (agents) {
agents.remove(agent);
}
}
public Map<String, Class<? extends Agent>> getAgents() {
final ConfigurationProvider configuration = Services.getInstance().getConfigurationProvider();
if (configuration != null) {
return configuration.getAgents();
}
return Collections.emptyMap();
}
// <editor-fold defaultstate="collapsed" desc="interface RunnableService">
@Override
public void injectArguments(Command command) {
command.setArgument("agentService", this);
}
@Override
public void initialize(final StructrServices services) throws ClassNotFoundException, InstantiationException, IllegalAccessException {
}
@Override
public void initialized() {}
@Override
public void shutdown() {}
@Override
public void startService() throws Exception {
run = true;
this.start();
}
@Override
public void stopService() {
run = false;
}
@Override
public boolean runOnStartup() {
return (true);
}
// </editor-fold>
// <editor-fold defaultstate="collapsed" desc="private methods">
private void assignNextAgentForTask(Task nextTask) {
Class taskClass = nextTask.getClass();
List<Agent> agents = getRunningAgentsForTask(taskClass);
// need to synchronize on agents
synchronized (agents) {
// find next free agent (agents should be sorted by load, so one
// of the first should do..
for (Agent agent : agents) {
if (agent.assignTask(nextTask)) {
// ok, task is assigned
logger.debug("Task assigned to agent {}", agent.getName());
return;
}
}
}
// FIXME: find better solution for hard limit here!
if (agents.size() < maxAgents) {
// if we get here, task was not assigned to any agent, need to
// create a new one.
Agent agent = createAgent(nextTask);
if ((agent != null) && agent.assignTask(nextTask)) {
agent.start();
} else {
// re-add task..
synchronized (taskQueue) {
taskQueue.add(nextTask);
}
}
} else {
logger.debug("Overall agents limit reached, re-queueing task");
// re-add task..
synchronized (taskQueue) {
taskQueue.add(nextTask);
}
}
}
/**
* Creates a new agent for the given Task. Note that the agent must be
* started manually after creation.
*
* @param forTask
* @return a new agent for the given task
*/
private Agent createAgent(Task forTask) {
Agent agent = null;
try {
agent = lookupAgent(forTask);
if (agent != null) {
// register us in agent..
agent.setAgentService(this);
}
} catch (Exception ex) {
// TODO: handle exception etc..
}
return (agent);
}
private Agent lookupAgent(Task task) {
// FIXME: superuser security context
Class taskClass = task.getClass();
Agent agent = null;
Class agentClass = agentClassCache.get(taskClass.getName());
// cache miss
if (agentClass == null) {
Map<String, Class<? extends Agent>> agentClassesMap = getAgents();
if (agentClassesMap != null) {
for (Entry<String, Class<? extends Agent>> classEntry : agentClassesMap.entrySet()) {
Class<? extends Agent> supportedAgentClass = agentClassesMap.get(classEntry.getKey());
try {
Agent supportedAgent = supportedAgentClass.newInstance();
Class supportedTaskClass = supportedAgent.getSupportedTaskType();
if (supportedTaskClass.equals(taskClass)) {
agentClass = supportedAgentClass;
}
agentClassCache.put(supportedTaskClass.getName(), supportedAgentClass);
} catch (Throwable ignore) {}
}
}
}
if (agentClass != null) {
try {
agent = (Agent) agentClass.newInstance();
} catch (Throwable ignore) {}
}
return (agent);
}
// </editor-fold>
//~--- get methods ----------------------------------------------------
/**
* Returns the current queue of remaining tasks.
* @return tasks
*/
public Collection<Task> getTaskQueue() {
return (taskQueue);
}
/**
* Returns the current collection of running agents.
* @return agents
*/
public Map<String, List<Agent>> getRunningAgents() {
return (runningAgents);
}
private List<Agent> getRunningAgentsForTask(Class taskClass) {
List<Agent> agents = runningAgents.get(taskClass.getName());
if (agents == null) {
agents = Collections.synchronizedList(new LinkedList<Agent>());
// Hashtable is synchronized
runningAgents.put(taskClass.getName(), agents);
}
return (agents);
}
@Override
public boolean isRunning() {
return (this.run);
}
@Override
public boolean isVital() {
return false;
}
}