package org.apache.s4.core;
import java.io.File;
import java.io.IOException;
import java.util.ArrayList;
import java.util.List;
import java.util.jar.Attributes.Name;
import java.util.jar.JarFile;
import org.apache.s4.base.util.S4RLoader;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import ch.qos.logback.classic.Level;
import com.google.common.io.PatternFilenameFilter;
import com.google.inject.AbstractModule;
import com.google.inject.Guice;
import com.google.inject.Inject;
import com.google.inject.Injector;
import com.google.inject.name.Named;
/**
* The Server instance coordinates activities in a cluster node including loading and unloading of applications and
* instantiating the communication layer.
*/
public class Server {
private static final Logger logger = LoggerFactory.getLogger(Server.class);
final private String commModuleName;
final private String logLevel;
public static final String MANIFEST_S4_APP_CLASS = "S4-App-Class";
// NOTE: currently we use a directory, but this will be changed by a URL (ref to zookeeper?),
// so that applications can be downloaded from a remote repository
final private String appsDir;
List<App> apps = new ArrayList<App>();
/**
*
*/
@Inject
public Server(@Named("comm.module") String commModuleName, @Named("s4.logger_level") String logLevel,
@Named("appsDir") String appsDir) {
this.commModuleName = commModuleName;
this.logLevel = logLevel;
this.appsDir = appsDir;
}
public void start() throws Exception {
/* Set up logger basic configuration. */
ch.qos.logback.classic.Logger root = (ch.qos.logback.classic.Logger) LoggerFactory
.getLogger(Logger.ROOT_LOGGER_NAME);
root.setLevel(Level.toLevel(logLevel));
Injector injector;
AbstractModule module = null;
/* Initialize communication layer module. */
try {
module = (AbstractModule) Class.forName(commModuleName).newInstance();
} catch (Exception e) {
logger.error("Unable to instantiate communication layer module.", e);
}
/* After some indirection we get the injector. */
injector = Guice.createInjector(module);
Sender sender = injector.getInstance(Sender.class);
Receiver receiver = injector.getInstance(Receiver.class);
// File[] s4rFiles = new File(appsDir).listFiles(new PatternFilenameFilter("\\w+\\.s4r"));
File[] s4rFiles = new File(appsDir).listFiles(new PatternFilenameFilter(".+.s4r"));
for (File s4rFile : s4rFiles) {
logger.info("Loading app: " + s4rFile.getPath());
loadApp(sender, receiver, s4rFile);
}
/* Now init + start apps. TODO: implement dynamic loading/unloading using ZK. */
for (App app : apps) {
logger.info("Starting app " + app.getClass().getName());
app.init();
app.start();
}
logger.info("Completed applications startup.");
}
private void loadApp(Sender sender, Receiver receiver, File s4r) {
S4RLoader cl = new S4RLoader(s4r.getAbsolutePath());
try {
JarFile s4rFile = new JarFile(s4r);
if (s4rFile.getManifest() == null) {
logger.warn("Cannot load s4r archive [{}] : missing manifest file");
return;
}
if (!s4rFile.getManifest().getMainAttributes().containsKey(new Name(MANIFEST_S4_APP_CLASS))) {
logger.warn("Cannot load s4r archive [{}] : missing attribute [{}] in manifest", s4r.getAbsolutePath(),
MANIFEST_S4_APP_CLASS);
return;
}
String appClassName = s4rFile.getManifest().getMainAttributes().getValue(MANIFEST_S4_APP_CLASS);
logger.info("App class name is: " + appClassName);
App app = null;
try {
Object o = (cl.loadClass(appClassName)).newInstance();
app = (App) o;
} catch (Exception e) {
logger.error("Could not load s4 application form s4r file [{" + s4r.getAbsolutePath() + "}]", e);
return;
}
app.setCommLayer(sender, receiver);
apps.add(app);
} catch (IOException e) {
logger.error("Could not load s4 application form s4r file [{" + s4r.getAbsolutePath() + "}]", e);
}
}
}