Added lots of metrics for pools and sessions.

cdstar-backend-nio/src/main/java/de/gwdg/cdstar/pool/nio/NioPool.java

@@ -6,6 +6,7 @@ import java.io.OutputStream;
 import java.nio.channels.Channels;
 import java.nio.channels.ReadableByteChannel;
 import java.nio.file.FileAlreadyExistsException;
+import java.nio.file.FileStore;
 import java.nio.file.FileVisitResult;
 import java.nio.file.Files;
 import java.nio.file.InvalidPathException;
@@ -27,6 +28,7 @@ import org.slf4j.LoggerFactory;
 
 import com.github.benmanes.caffeine.cache.Caffeine;
 import com.github.benmanes.caffeine.cache.LoadingCache;
+import com.github.benmanes.caffeine.cache.stats.CacheStats;
 
 import de.gwdg.cdstar.MultiDigest;
 import de.gwdg.cdstar.Utils;
@@ -70,6 +72,7 @@ public class NioPool implements StoragePool {
 	NioRecoveryHandler recoveryHandler;
 
 	LoadingCache<Path, JsonIndex> indexCache;
+	private PoolStats stats;
 
 	public NioPool(Config cfg) throws IOException, ConfigException {
 		// TODO: Make more than just the path configurable
@@ -89,6 +92,8 @@ public class NioPool implements StoragePool {
 				// Allow GC to shrink the heap during idle hours.
 				.expireAfterAccess(60, TimeUnit.SECONDS)
 				.build(this::loadFromDisk);
+
+		stats = new PoolStats();
 	}
 
 	@Override
@@ -337,4 +342,46 @@ public class NioPool implements StoragePool {
 		return false;
 	}
 
+	public PoolStats getStats() {
+		return stats;
+	}
+
+	public class PoolStats {
+		public CacheStats getCacheStats() {
+			return indexCache.stats();
+		}
+
+		public long getDiskTotal() {
+			long total = 0;
+			for (FileStore store : basePath.getFileSystem().getFileStores()) {
+				try {
+					total = store.getTotalSpace();
+				} catch (IOException e) {
+					continue;
+				}
+			}
+			return total;
+		}
+
+		public long getDiskFree() {
+			long usable = 0;
+			for (FileStore store : basePath.getFileSystem().getFileStores()) {
+				try {
+					usable = store.getUsableSpace();
+				} catch (IOException e) {
+					continue;
+				}
+			}
+			return usable;
+		}
+
+		public long cacheHitCount() {
+			return indexCache.stats().hitCount();
+		}
+
+		public long cacheMissCount() {
+			return indexCache.stats().missCount();
+		}
+	}
+
 }

cdstar-runtime/src/main/java/de/gwdg/cdstar/runtime/services/SessionRegistry.java

@@ -5,10 +5,14 @@ import java.util.concurrent.ConcurrentHashMap;
 import java.util.concurrent.ScheduledFuture;
 import java.util.concurrent.TimeUnit;
 import java.util.concurrent.TimeoutException;
+import java.util.concurrent.atomic.AtomicLong;
+import java.util.function.Predicate;
 
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
+import com.codahale.metrics.MetricRegistry;
+
 import de.gwdg.cdstar.runtime.RuntimeContext;
 import de.gwdg.cdstar.runtime.client.CDStarSession;
 import de.gwdg.cdstar.runtime.listener.RuntimeListener;
@@ -19,12 +23,21 @@ public class SessionRegistry implements SessionStartListener, SessionListener, R
 	private final ConcurrentHashMap<String, CDStarSession> allSessions = new ConcurrentHashMap<>();
 
 	private ScheduledFuture<?> sessionReaper;
+	private final AtomicLong totalCounter = new AtomicLong();
 
 	private static final Logger log = LoggerFactory.getLogger(SessionRegistry.class);
 
 	@Override
 	public void onStartup(RuntimeContext ctx) throws Exception {
 		sessionReaper = ctx.lookupRequired(CronService.class).schedule(this::reapExpiredSessions, 10, TimeUnit.SECONDS);
+		ctx.lookup(MetricRegistry.class).ifPresent(mr -> {
+			mr.gauge("sess.open", () -> () -> allSessions.size());
+			mr.gauge("sess.open.ro", () -> () -> allSessions.values().stream()
+					.filter(CDStarSession::isReadOnly).count());
+			mr.gauge("sess.open.rw", () -> () -> allSessions.values().stream()
+					.filter(((Predicate<CDStarSession>)CDStarSession::isReadOnly).negate()).count());
+			mr.gauge("sess.total", () -> () -> totalCounter.get());
+		});
 	}
 
 	private void reapExpiredSessions() {
@@ -56,6 +69,7 @@ public class SessionRegistry implements SessionStartListener, SessionListener, R
 	@Override
 	public void onSessionStarted(CDStarSession session) {
 		allSessions.put(session.getSessionId(), session);
+		totalCounter.incrementAndGet();
 		session.addListener(this);
 	}
 

cdstar-runtime/src/main/java/de/gwdg/cdstar/runtime/services/VaultRegistry.java

@@ -19,12 +19,15 @@ import java.util.stream.Stream;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
+import com.codahale.metrics.MetricRegistry;
+
 import de.gwdg.cdstar.Utils;
 import de.gwdg.cdstar.config.ConfigLoader;
 import de.gwdg.cdstar.config.MapConfig;
 import de.gwdg.cdstar.pool.PoolError;
 import de.gwdg.cdstar.pool.StoragePool;
 import de.gwdg.cdstar.pool.nio.NioPool;
+import de.gwdg.cdstar.pool.nio.NioPool.PoolStats;
 import de.gwdg.cdstar.runtime.Config;
 import de.gwdg.cdstar.runtime.ConfigException;
 import de.gwdg.cdstar.runtime.RuntimeContext;
@@ -200,6 +203,9 @@ public class VaultRegistry implements RuntimeListener {
 				if (!StoragePool.class.isAssignableFrom(poolClass))
 					throw new ConfigException("Pool does not implement " + StoragePool.class.getName());
 				vci.pool = (StoragePool) poolClass.getConstructor(Config.class).newInstance(scoped);
+
+				addMetrics(vci);
+
 				return vci.pool;
 			} catch (final Exception e) {
 				if (e instanceof PoolError)
@@ -209,6 +215,24 @@ public class VaultRegistry implements RuntimeListener {
 		}
 	}
 
+	private void addMetrics(VaultConfigImpl vci) {
+		if(vci.pool instanceof NioPool) {
+
+			runtime.lookup(MetricRegistry.class).ifPresent(mr -> {
+				String name = "pool."+vci.getName();
+				NioPool pool = (NioPool) vci.pool;
+				PoolStats poolStats = pool.getStats();
+
+				mr.gauge(name+".cache.hit", () -> () -> poolStats.cacheHitCount());
+				mr.gauge(name+".cache.miss", () -> () -> poolStats.cacheMissCount());
+				mr.gauge(name+".disk.total", () -> () -> poolStats.getDiskTotal());
+				mr.gauge(name+".disk.free", () -> () -> poolStats.getDiskFree());
+
+			});
+		}
+
+	}
+
 	private boolean isValidVaultName(String name) {
 		return vaultNamePattern.matcher(name).matches();
 	}