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A tool to start/stop a background fuseki server.
The newest version!
package io.opencaesar.owl.fuseki;
import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.FileReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.io.OutputStreamWriter;
import java.net.HttpURLConnection;
import java.net.URISyntaxException;
import java.net.URL;
import java.nio.file.Path;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collections;
import java.util.List;
import java.util.Optional;
import java.util.zip.ZipEntry;
import java.util.zip.ZipInputStream;
import org.apache.log4j.Appender;
import org.apache.log4j.AppenderSkeleton;
import org.apache.log4j.Level;
import org.apache.log4j.LogManager;
import org.apache.log4j.Logger;
import org.apache.log4j.xml.DOMConfigurator;
import org.apache.maven.repository.internal.MavenRepositorySystemUtils;
import org.apache.maven.resolver.owl.fuseki.ManualRepositorySystemFactory;
import org.eclipse.aether.DefaultRepositorySystemSession;
import org.eclipse.aether.RepositorySystem;
import org.eclipse.aether.artifact.Artifact;
import org.eclipse.aether.artifact.DefaultArtifact;
import org.eclipse.aether.collection.CollectRequest;
import org.eclipse.aether.collection.CollectResult;
import org.eclipse.aether.collection.DependencyCollectionException;
import org.eclipse.aether.graph.Dependency;
import org.eclipse.aether.graph.DependencyNode;
import org.eclipse.aether.graph.DependencyVisitor;
import org.eclipse.aether.repository.LocalRepository;
import org.eclipse.aether.repository.RemoteRepository;
import org.eclipse.aether.resolution.ArtifactRequest;
import org.eclipse.aether.resolution.ArtifactResolutionException;
import org.eclipse.aether.resolution.ArtifactResult;
import com.beust.jcommander.IStringConverter;
import com.beust.jcommander.JCommander;
import com.beust.jcommander.Parameter;
import com.beust.jcommander.ParameterException;
/**
* Start an Apache Fuseki server, either in headless mode or with a web UI.
* This application resolves the Apache Fuseki dependencies from a remote maven repository
* so that it can be safely be used as a Gradle task.
*/
public class FusekiApp {
/**
* The file that will contain the PID of the fuseki server
*/
public static final String PID_FILENAME = "fuseki.pid";
/**
* The log file for the fuseki server output.
*/
public static final String LOG_FILENAME = "fuseki.log";
enum Command {
start,
stop
}
@Parameter(
names = {"--command", "-c"},
description = "An enumerated command: start or stop (Required)",
converter = CommandConverter.class,
required = true,
order = 1)
private Command command;
@Parameter(
names = {"--configurationPath", "-g"},
description = "A path to a configuration file (Required)",
order = 2)
private String configurationPath;
@Parameter(
names = {"--outputFolderPath", "-o"},
description = "A path to an output folder (Required)",
required = true,
order = 3)
private String outputFolderPath;
@Parameter(
names = {"--remote-repository-url", "-url"},
description = "URL for a remote repository like Maven Central, defaults to: https://repo.maven.apache.org/maven2/",
required = false,
order = 4)
private String remoteRepositoryURL = "https://repo.maven.apache.org/maven2/";
@Parameter(
names = {"--fuseki-version", "-fv"},
description = "Version of Fuseki, defaults to 4.6.0",
required = false,
order = 5)
private String fusekiVersion = "4.6.1";
@Parameter(
names = {"--port", "-p"},
description = "Fuseki server port (defaults to 3030)",
required = false,
order = 6)
private int port = 3030;
@Parameter(
names = {"--webui", "-ui"},
description = "Starts the Fuseki UI instead of the headless Fuseki server (Optional)",
required = false,
order = 7)
private boolean webui = false;
@Parameter(
names = {"--max-pings", "-n"},
description = "Maximum number (10 by default) of pings to the server before giving up",
help = true,
required = false,
order = 8)
private int maxPings = 10;
@Parameter(
names = {"--classpath", "-cp"},
description = "Additional classpath dependencies to load when starting Fuseki, each of the form: ::",
required = false,
order = 9)
private List classpath = new ArrayList<>();
@Parameter(
names = {"jvm-arguments", "-jvm"},
description = "Additional JVM arguments",
required = false,
order = 10)
private List jvmArguments = new ArrayList<>();
@Parameter(
names = {"--debug", "-d"},
description = "Shows debug logging statements",
order = 11)
private boolean debug = false;
@Parameter(
names = {"--help", "-h"},
description = "Displays summary of options",
help = true,
order = 12)
private boolean help = false;
private final static Logger LOGGER = Logger.getLogger(FusekiApp.class);
static {
DOMConfigurator.configure(ClassLoader.getSystemClassLoader().getResource("log4j.xml"));
}
/**
* Application for starting a Fuseki server.
* @param args Application arguments.
* @throws Exception Error
*/
public static void main(final String... args) throws Exception {
final FusekiApp app = new FusekiApp();
final JCommander builder = JCommander.newBuilder().addObject(app).build();
builder.parse(args);
if (app.command == Command.start && app.configurationPath == null) {
throw new IllegalArgumentException("The 'configurationPath' paramter is not specified");
}
if (app.help) {
builder.usage();
return;
}
if (app.debug) {
final Appender appender = LogManager.getRootLogger().getAppender("stdout");
if (appender instanceof AppenderSkeleton)
((AppenderSkeleton) appender).setThreshold(Level.DEBUG);
}
app.run(app);
}
/**
* Creats a new FusekiApp object
*/
public FusekiApp() {
}
private void run(FusekiApp app) throws Exception {
LOGGER.info("=================================================================");
LOGGER.info(" S T A R T");
LOGGER.info(" OWL Fuseki " + getAppVersion());
LOGGER.info("=================================================================");
LOGGER.info(("Command = " + command));
LOGGER.info(("Fuseki version = " + fusekiVersion));
LOGGER.info(("Output folder path = " + outputFolderPath));
if (command == Command.start) {
RepositorySystem repositorySystem = ManualRepositorySystemFactory.newRepositorySystem();
DefaultRepositorySystemSession session = newRepositorySystemSession(repositorySystem);
List repositories = newRepositories(remoteRepositoryURL);
final List deps = new ArrayList<>();
collectDependencies(repositorySystem, session, repositories, newFusekiServerArtifact(fusekiVersion), deps);
if (app.webui) {
collectDependencies(repositorySystem, session, repositories, newFusekiWebAppArtifact(fusekiVersion), deps);
final File webappFolder = new File(outputFolderPath).toPath().resolve("webapp").toFile();
webappFolder.mkdirs();
ArtifactResult fusekiWar = resolveArtifact(
repositorySystem,
session,
repositories,
newFusekiWarArtifact(fusekiVersion));
if (!fusekiWar.isResolved())
throw new IllegalArgumentException("Failed to resolve Fuseki War version "+fusekiVersion);
final File fusekiWarFile = fusekiWar.getArtifact().getFile();
try (InputStream is = new FileInputStream(fusekiWarFile)) {
unzip(is, webappFolder);
}
String[] cpEntries = deps.toArray(new String[0]);
startFuseki(cpEntries, new File(configurationPath), new File(outputFolderPath), app.port, false, app.maxPings, "org.apache.jena.fuseki.cmd.FusekiCmd", app.jvmArguments, "--localhost");
} else {
String[] cpEntries = deps.toArray(new String[0]);
startFuseki(cpEntries, new File(configurationPath), new File(outputFolderPath), app.port, true, app.maxPings, "org.apache.jena.fuseki.main.cmds.FusekiMainCmd", app.jvmArguments);
}
} else {
stopFuseki(new File(outputFolderPath));
}
LOGGER.info("=================================================================");
LOGGER.info(" E N D");
LOGGER.info("=================================================================");
}
/**
* Extract an input zip archive stream to a target folder
* @param source an input stream of a zip archive
* @param target a target directory where to extract the zip contents.
* @throws IOException error
*/
public static void unzip(InputStream source, File target) throws IOException {
final ZipInputStream zipStream = new ZipInputStream(source);
ZipEntry nextEntry;
while ((nextEntry = zipStream.getNextEntry()) != null) {
final String name = nextEntry.getName();
// only extract files
if (!name.endsWith("/")) {
final File nextFile = new File(target, name);
// create directories
final File parent = nextFile.getParentFile();
if (parent != null) {
//noinspection ResultOfMethodCallIgnored
parent.mkdirs();
}
// write file
// Skipping writing the file if it exists turns out to be a bad idea.
// - changes in the version of Fuseki could cause problems.
// - without changes, the webapp ui is not displaying properly.
// So it is better to always overwrite existing files.
try (OutputStream targetStream = new FileOutputStream(nextFile)) {
copy(zipStream, targetStream);
}
}
}
}
/**
* Starts a background Fuseki server from a Fuseki configuration file.
*
* @param cpEntries Classpath entries
* @param config Absolute path to a Fuseki configuration file.
* @param fusekiDir Path to an output directory that, if it exists, will be cleaned, and that will have:
* - fuseki.log the combination of standard output and error.
* - fuseki.pid the ID of the fuseki process.
* @param port The port that the Fuseki server will be listening on.
* @param pingArg Whether to add --ping to the command
* @param maxPings The maximum number of pings to try before giving up
* @param clazz Qualified name of the Fuseki server application (with or without Web UI)
* @param jvmArgs A list of additional JVM arguments.
* @param argv Additional arguments
* @throws IOException if the 'fuseki.pid' file could not be written to
* @throws URISyntaxException If there is a problem retrieving the location of the fuseki jar.
*/
public static void startFuseki(
String[] cpEntries,
File config,
File fusekiDir,
int port,
boolean pingArg,
int maxPings,
String clazz,
List jvmArgs,
String... argv) throws IOException, URISyntaxException {
Path output = fusekiDir.toPath();
File pidFile = output.resolve(PID_FILENAME).toFile();
File logFile = output.resolve(LOG_FILENAME).toFile();
// Check if the server is already running
Optional pid = findFusekiProcessId(pidFile);
if (pid.isPresent()) {
Optional ph = findProcess(pid.get());
if (ph.isPresent()) {
LOGGER.warn("Fuseki server is already running with pid=" + ph.get().pid());
return;
}
pidFile.delete();
}
// Start the server
fusekiDir.mkdirs();
List args = new ArrayList();
args.add(getJavaCommandPath());
args.addAll(jvmArgs);
args.add("-cp");
args.add(String.join(File.pathSeparator, cpEntries));
args.add(clazz);
if (pingArg) {
args.add("--ping");
}
args.add("--config=" + output.relativize(config.toPath()).toString().replace("\\", "/")); // put the relative path to avoid spaces in path
args.add("--port");
args.add(Integer.toString(port));
args.addAll(Arrays.asList(argv));
ProcessBuilder pb = new ProcessBuilder(args);
pb.directory(output.toFile());
pb.redirectErrorStream(true);
pb.redirectOutput(logFile);
Process p = pb.start();
try {
Thread.sleep(2000); // give server a bit of time to start
} catch (InterruptedException e) {
// do nothing
}
// Check that the newly started server is alive
if (!p.isAlive()) {
throw new RuntimeException("Fuseki server has failed to start with exit code: " + p.exitValue() + ". See " + logFile + " for more details.");
} else if (maxPings > 0) {
// Ping the server a max number of times until it responds
int ping = 0;
while (++ping <= maxPings) {
if (pingServer(port)) {
LOGGER.warn("Fuseki server has now successfully started with pid=" + p.pid() + ", listening on http://localhost:" + port);
break;
}
try {
Thread.sleep(2000); // wait before the next ping
} catch (InterruptedException e) {
// do nothing
}
}
// if the server has failed to respond, kill it
if (ping > maxPings) {
try {
p.destroyForcibly().waitFor();
} catch (InterruptedException e) {
// do nothing
}
throw new IllegalArgumentException("Fuseki server has failed to respond after " + maxPings + " pings and now been killed");
}
}
// Create the pid file and record the pid of the server in it
OutputStreamWriter os = new OutputStreamWriter(new FileOutputStream(pidFile));
BufferedWriter w = new BufferedWriter(os);
w.write(Long.toString(p.pid()));
w.newLine();
w.close();
os.close();
}
/**
* Stops a background Fuseki server.
*
* @param fusekiDir The directory containing the fuseki.pid file with the ID of the Fuseki server process to kill.
* @throws IOException if the 'fuseki.pid' file could be read
*/
public static void stopFuseki(File fusekiDir) throws IOException {
File pidFile = fusekiDir.toPath().resolve(PID_FILENAME).toFile();
Optional pid = findFusekiProcessId(pidFile);
if (!pid.isEmpty()) {
Optional ph = findProcess(pid.get());
if (ph.isPresent()) {
if (!ph.get().destroyForcibly()) {
throw new IllegalArgumentException("Failed to kill a Fuseki server process with pid=" + pid.get());
} else {
LOGGER.warn("Fuseki server with pid=" + pid.get() + " has been stopped");
}
}
pidFile.delete();
}
}
private static boolean pingServer(int port) throws IOException {
URL url = new URL("http://localhost:" + port + "/$/ping");
HttpURLConnection con = (HttpURLConnection) url.openConnection();
int responseCode = HttpURLConnection.HTTP_NOT_FOUND;
try {
con.setRequestMethod("GET");
responseCode = con.getResponseCode();
} catch (Exception e) {
LOGGER.error("Fuseki server has not yet responded to ping");
} finally {
con.disconnect();
}
return responseCode == HttpURLConnection.HTTP_OK;
}
private static void copy(final InputStream source, final OutputStream target) throws IOException {
final int bufferSize = 4 * 1024;
final byte[] buffer = new byte[bufferSize];
int nextCount;
while ((nextCount = source.read(buffer)) >= 0) {
target.write(buffer, 0, nextCount);
}
}
/**
* @return Application version.
*/
private String getAppVersion() {
var version = this.getClass().getPackage().getImplementationVersion();
return (version != null) ? version : "";
}
/**
* A parameter converter for the command enumeration (start/stop).
*/
public static class CommandConverter implements IStringConverter {
/**
* Creates a new CommandConverter object
*/
public CommandConverter() {
}
@Override
public Command convert(String value) {
try {
return Command.valueOf(value);
} catch (IllegalArgumentException e) {
throw new ParameterException("Value " + value + " is not valid (only: start or stop)");
}
}
}
/**
* Find the fuseki process id from the '.fuseki.pid' file in the given directory
*
* @param f The 'fuseki.pid' file.
* @return An optional containing the process id
* @throws IOException if the 'fuseki.pid' file could not be read
*/
public static Optional findFusekiProcessId(File f) throws IOException {
if (!f.exists() || !f.canRead())
return Optional.empty();
BufferedReader r = new BufferedReader(new FileReader(f));
String s = r.readLine();
r.close();
long pid = Long.parseLong(s);
return Optional.of(pid);
}
/**
* Find a process handle given a process id.
*
* @param pid The process id
* @return The process handle of the given process id
*/
public static Optional findProcess(long pid) {
return ProcessHandle
.allProcesses()
.filter(p -> p.pid() == pid)
.findFirst();
}
/**
* Find the path to the java executable (java.exe on windows, java elsewhere).
*
* @return The absolute path to the java executable.
*/
public static String getJavaCommandPath() {
String javaHome = System.getProperty("java.home");
String osName = System.getProperty("os.name");
boolean isWindows = (null != osName) && osName.startsWith("Windows");
String javaExe = javaHome + File.separator + "bin" + File.separator + "java" + (isWindows ? ".exe" : "");
File java = new File(javaExe);
if (java.exists() && java.canExecute())
return javaExe;
else
throw new RuntimeException("Cannot find java executable at: " + javaExe);
}
/**
* Returns the jena-fuseki-server artifact for the given version.
*
* @param version requested artifact version
* @return Artifact
*/
public static Artifact newFusekiServerArtifact(String version) {
return new DefaultArtifact("org.apache.jena:jena-fuseki-server:"+version);
}
/**
* Returns the jena-fuseki-webapp artifact for the given version.
*
* @param version requested artifact version
* @return Artifact
*/
public static Artifact newFusekiWebAppArtifact(String version) {
return new DefaultArtifact("org.apache.jena:jena-fuseki-webapp:"+version);
}
/**
* Returns the jena-fuseki-war artifact for the given version.
*
* @param version requested artifact version
* @return Artifact
*/
public static Artifact newFusekiWarArtifact(String version) {
return new DefaultArtifact("org.apache.jena:jena-fuseki-war:war:"+version);
}
private static void collectDependencies(RepositorySystem system,
DefaultRepositorySystemSession session,
List repositories,
Artifact artifact,
List deps) throws DependencyCollectionException {
CollectResult fusekiDeps = resolveDependencies(
system,
session,
repositories,
artifact);
fusekiDeps.getRoot().accept(new DependencyVisitor() {
@Override
public boolean visitEnter(DependencyNode node) {
Artifact a = node.getArtifact();
try {
ArtifactResult r = resolveArtifact(system, session, repositories, a);
deps.add(r.getArtifact().getFile().getAbsolutePath());
} catch (ArtifactResolutionException e) {
throw new RuntimeException(e);
}
return true;
}
@Override
public boolean visitLeave(DependencyNode node) {
return true;
}
});
}
private static CollectResult resolveDependencies(RepositorySystem system,
DefaultRepositorySystemSession session,
List repositories,
Artifact artifact) throws DependencyCollectionException {
CollectRequest collectRequest = new CollectRequest();
collectRequest.setRoot(new Dependency(artifact, ""));
collectRequest.setRepositories(repositories);
CollectResult result = system.collectDependencies(session, collectRequest);
return result;
}
private static ArtifactResult resolveArtifact(RepositorySystem system,
DefaultRepositorySystemSession session,
List repositories,
Artifact artifact) throws ArtifactResolutionException {
ArtifactRequest req = new ArtifactRequest();
req.setArtifact(artifact);
req.setRepositories(repositories);
ArtifactResult res = system.resolveArtifact( session, req);
return res;
}
/*
* Similar to https://github.com/apache/maven-resolver/blob/0572277e23f5c2f2643dacf8bc8b8ea1ba031dea/maven-resolver-demos/maven-resolver-demo-snippets/src/main/java/org/apache/maven/resolver/examples/util/Booter.java#L71
* The difference is that the local repository is ~/.m2/repository
*/
private static DefaultRepositorySystemSession newRepositorySystemSession(RepositorySystem system) throws IOException {
DefaultRepositorySystemSession session = MavenRepositorySystemUtils.newSession();
File home = new File(System.getProperty("user.home"));
if (!home.isDirectory() || !home.canExecute())
throw new IllegalArgumentException("user.home is not a directory: "+home);
File m2 = home.toPath().resolve(".m2").toFile();
if (!m2.exists())
m2.mkdirs();
if (!m2.exists())
throw new IllegalArgumentException("Cannot create ~/.m2");
File local = m2.toPath().resolve("repository").toFile();
if (!local.exists())
local.mkdirs();
if (!local.exists())
throw new IllegalArgumentException("Cannot create ~/.m2/repository");
LocalRepository localRepo = new LocalRepository( local );
session.setLocalRepositoryManager( system.newLocalRepositoryManager( session, localRepo ) );
session.setTransferListener( new ConsoleTransferListener() );
session.setRepositoryListener( new ConsoleRepositoryListener() );
return session;
}
private static List newRepositories(String mavenCentralURL)
{
return new ArrayList<>( Collections.singletonList( newCentralRepository(mavenCentralURL) ) );
}
private static RemoteRepository newCentralRepository(String mavenCentralURL)
{
return new RemoteRepository.Builder( "central", "default", mavenCentralURL).build();
}
}