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package org.opentripplanner.routing.impl;
import com.fasterxml.jackson.core.JsonParser;
import com.fasterxml.jackson.databind.JsonNode;
import com.fasterxml.jackson.databind.ObjectMapper;
import com.fasterxml.jackson.databind.node.MissingNode;
import com.google.common.io.ByteStreams;
import org.opentripplanner.routing.graph.Graph;
import org.opentripplanner.routing.services.GraphSource;
import org.opentripplanner.routing.services.StreetVertexIndexFactory;
import org.opentripplanner.standalone.Router;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import java.io.*;
/**
* The primary implementation of the GraphSource interface. The graph is loaded from a serialized
* graph from a given source.
*
*/
public class InputStreamGraphSource implements GraphSource {
public static final String GRAPH_FILENAME = "Graph.obj";
private static final Logger LOG = LoggerFactory.getLogger(InputStreamGraphSource.class);
/**
* Delay before starting to load a graph after the last modification time. In case of writing,
* we expect graph last modification time to be updated at at least that frequency. If not, you
* can either increase this value, or use an atomic move when copying the file.
* */
private static final long LOAD_DELAY_SEC = 10;
private Router router;
private String routerId;
private long graphLastModified = 0L;
private Object preEvictMutex = new Boolean(false);
/**
* The current used input stream implementation for getting graph data source.
*/
private Streams streams;
// TODO Why do we need a factory? There is a single one implementation.
private StreetVertexIndexFactory streetVertexIndexFactory = new DefaultStreetVertexIndexFactory();
/**
* @return A GraphSource loading graph from the file system under a base path.
*/
public static InputStreamGraphSource newFileGraphSource(String routerId, File path) {
return new InputStreamGraphSource(routerId, new FileStreams(path));
}
/**
* @return A GraphSource loading graph from an embedded classpath resources (a graph bundled
* inside a pre-packaged WAR for example).
*/
public static InputStreamGraphSource newClasspathGraphSource(String routerId, File path) {
return new InputStreamGraphSource(routerId, new ClasspathStreams(path));
}
private InputStreamGraphSource(String routerId, Streams streams) {
this.routerId = routerId;
this.streams = streams;
}
@Override
public Router getRouter() {
/*
* We synchronize on pre-evict mutex in case we are in the middle of reloading in pre-evict
* mode. In that case we must make the client wait until the new graph is loaded, because
* the old one is gone to the GC. Performance hit should be low as getGraph() is not called
* often.
*/
synchronized (preEvictMutex) {
return router;
}
}
@Override
public boolean reload(boolean force, boolean preEvict) {
/* We synchronize on 'this' to prevent multiple reloads from being called at the same time */
synchronized (this) {
long lastModified = streams.getLastModified();
boolean doReload = force ? true : checkAutoReload(lastModified);
if (!doReload)
return true;
if (preEvict) {
synchronized (preEvictMutex) {
if (router != null) {
LOG.info("Reloading '{}': pre-evicting router", routerId);
router.shutdown();
}
/*
* Forcing router to null here should remove any references to the graph once
* all current requests are done. So the next reload is supposed to have more
* memory.
*/
router = null;
router = loadGraph();
}
} else {
Router newRouter = loadGraph();
if (newRouter != null) {
// Load OK
if (router != null) {
LOG.info("Reloading '{}': post-evicting router", routerId);
router.shutdown();
}
router = newRouter; // Assignment in java is atomic
} else {
// Load failed
if (force || router == null) {
LOG.warn("Unable to load data for router '{}'.", routerId);
if (router != null) {
router.shutdown();
}
router = null;
} else {
// No shutdown, since we keep current one.
LOG.warn("Unable to load data for router '{}', keeping old data.", routerId);
}
}
}
if (router == null) {
graphLastModified = 0L;
} else {
/*
* Note: we flag even if loading failed, because we want to wait for fresh new data
* before loading again.
*/
graphLastModified = lastModified;
}
// If a router is null, it will be evicted.
return (router != null);
}
}
/**
* Check if a graph has been modified since the last time it has been loaded.
*
* @param lastModified Time of last modification of current loaded data.
* @return True if the input data has been modified and need to be reloaded.
*/
private boolean checkAutoReload(long lastModified) {
// We check only for graph file modification, not config
long validEndTime = System.currentTimeMillis() - LOAD_DELAY_SEC * 1000;
LOG.debug(
"checkAutoReload router '{}' validEndTime={} lastModified={} graphLastModified={}",
routerId, validEndTime, lastModified, graphLastModified);
if (lastModified != graphLastModified && lastModified <= validEndTime) {
// Only reload graph modified more than 1 mn ago.
LOG.info("Router ID '{}' graph input modification detected, force reload.", routerId);
return true;
} else {
return false;
}
}
@Override
public void evict() {
synchronized (this) {
if (router != null) {
router.shutdown();
router = null;
}
}
}
/**
* Do the actual operation of graph loading. Load configuration if present, and startup the
* router with the help of the router lifecycle manager.
*/
private Router loadGraph() {
final Graph newGraph;
try (InputStream is = streams.getGraphInputStream()) {
LOG.info("Loading graph...");
try {
newGraph = Graph.load(is);
} catch (Exception ex) {
LOG.error("Exception while loading graph '{}'.", routerId, ex);
return null;
}
newGraph.routerId = (routerId);
} catch (IOException e) {
LOG.warn("Graph file not found or not openable for routerId '{}': {}", routerId, e);
return null;
}
// Decorate the graph TODO how are we "decorating" it? This appears to refer to loading its configuration.
// Even if a config file is not present on disk one could be bundled inside.
try (InputStream is = streams.getConfigInputStream()) {
JsonNode config = MissingNode.getInstance();
// TODO reuse the exact same JSON loader from OTPConfigurator
ObjectMapper mapper = new ObjectMapper();
mapper.configure(JsonParser.Feature.ALLOW_COMMENTS, true);
mapper.configure(JsonParser.Feature.ALLOW_UNQUOTED_FIELD_NAMES, true);
if (is != null) {
config = mapper.readTree(is);
} else if (newGraph.routerConfig != null) {
config = mapper.readTree(newGraph.routerConfig);
}
Router newRouter = new Router(routerId, newGraph);
newRouter.startup(config);
return newRouter;
} catch (IOException e) {
LOG.error("Can't read config file.");
LOG.error(e.getMessage());
return null;
}
}
/**
* InputStreamGraphSource delegates to some actual implementation the fact of getting the input
* stream and checking the last modification timestamp for a given routerId.
* FIXME this seems like a lot of boilerplate just to switch between FileInputStream and getResourceAsStream
* a couple of conditional blocks and a boolean field "onClasspath" might do the trick.
*/
private interface Streams {
public abstract InputStream getGraphInputStream() throws IOException;
public abstract InputStream getConfigInputStream() throws IOException;
public abstract long getLastModified();
}
private static class FileStreams implements Streams {
private File path;
private FileStreams(File path) {
this.path = path;
}
@Override
public InputStream getGraphInputStream() throws IOException {
File graphFile = new File(path, GRAPH_FILENAME);
LOG.debug("Loading graph from file '{}'", graphFile.getPath());
return new FileInputStream(graphFile);
}
@Override
public InputStream getConfigInputStream() throws IOException {
File configFile = new File(path, Router.ROUTER_CONFIG_FILENAME);
if (configFile.canRead()) {
LOG.debug("Loading config from file '{}'", configFile.getPath());
return new FileInputStream(configFile);
} else {
return null;
}
}
@Override
public long getLastModified() {
// Note: this returns 0L if the file does not exists
return new File(path, GRAPH_FILENAME).lastModified();
}
}
private static class ClasspathStreams implements Streams {
private File path;
private ClasspathStreams(File path) {
this.path = path;
}
@Override
public InputStream getGraphInputStream() {
File graphFile = new File(path, GRAPH_FILENAME);
LOG.debug("Loading graph from classpath at '{}'", graphFile.getPath());
return Thread.currentThread().getContextClassLoader()
.getResourceAsStream(graphFile.getPath());
}
@Override
public InputStream getConfigInputStream() {
File configFile = new File(path, Router.ROUTER_CONFIG_FILENAME);
LOG.debug("Trying to load config on classpath at '{}'", configFile.getPath());
return Thread.currentThread().getContextClassLoader()
.getResourceAsStream(configFile.getPath());
}
/**
* For a packaged classpath resources we assume the data won't change, so returning always
* 0L basically disable auto-reload in that case.
*/
@Override
public long getLastModified() {
return 0L;
}
}
/**
* A GraphSource factory creating InputStreamGraphSource from file.
*/
public static class FileFactory implements GraphSource.Factory {
private static final Logger LOG = LoggerFactory.getLogger(FileFactory.class);
public File basePath;
public FileFactory(File basePath) {
this.basePath = basePath;
}
@Override
public GraphSource createGraphSource(String routerId) {
return InputStreamGraphSource.newFileGraphSource(routerId, getBasePath(routerId));
}
@Override
public boolean save(String routerId, InputStream is) {
File sourceFile = new File(getBasePath(routerId), InputStreamGraphSource.GRAPH_FILENAME);
try {
// Create directory if necessary
File directory = new File(sourceFile.getParentFile().getPath());
if (!directory.exists()) {
directory.mkdir();
}
// Store the stream to disk, to be sure no data will be lost make a temporary backup
// file of the original file.
// Make backup file
File destFile = null;
if (sourceFile.exists()) {
destFile = new File(sourceFile.getPath() + ".bak");
if (destFile.exists()) {
destFile.delete();
}
sourceFile.renameTo(destFile);
}
// Store the stream
try (FileOutputStream os = new FileOutputStream(sourceFile)) {
ByteStreams.copy(is, os);
}
// And delete the backup file
sourceFile = new File(sourceFile.getPath() + ".bak");
if (sourceFile.exists()) {
sourceFile.delete();
}
} catch (Exception ex) {
LOG.error("Exception while storing graph to {}.", sourceFile.getPath(), ex);
return false;
}
return true;
}
private File getBasePath(String routerId) {
return new File(basePath, routerId);
}
}
}
