All Downloads are FREE. Search and download functionalities are using the official Maven repository.
  • Log In
  • Register

    • io.netty.util.ResourceLeakDetector Maven / Gradle / Ivy

    Go to download

    This artifact provides a single jar that contains all classes required to use remote Jakarta Enterprise Beans and Jakarta Messaging, including all dependencies. It is intended for use by those not using maven, maven users should just import the Jakarta Enterprise Beans and Jakarta Messaging BOM's instead (shaded JAR's cause lots of problems with maven, as it is very easy to inadvertently end up with different versions on classes on the class path).

    There is a newer version: 35.0.0.Beta1
    Show newest version
    /*
 * Copyright 2013 The Netty Project
 *
 * The Netty Project licenses this file to you under the Apache License,
 * version 2.0 (the "License"); you may not use this file except in compliance
 * with the License. You may obtain a copy of the License at:
 *
 *   http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
 * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
 * License for the specific language governing permissions and limitations
 * under the License.
 */

package io.netty.util;

import io.netty.util.internal.PlatformDependent;
import io.netty.util.internal.SystemPropertyUtil;
import io.netty.util.internal.logging.InternalLogger;
import io.netty.util.internal.logging.InternalLoggerFactory;

import java.lang.ref.PhantomReference;
import java.lang.ref.ReferenceQueue;
import java.util.ArrayDeque;
import java.util.Deque;
import java.util.EnumSet;
import java.util.concurrent.ConcurrentMap;
import java.util.concurrent.atomic.AtomicBoolean;

import static io.netty.util.internal.StringUtil.*;

public final class ResourceLeakDetector {

    private static final String PROP_LEVEL = "io.netty.leakDetectionLevel";
    private static final Level DEFAULT_LEVEL = Level.SIMPLE;

    /**
     * Represents the level of resource leak detection.
     */
    public enum Level {
        /**
         * Disables resource leak detection.
         */
        DISABLED,
        /**
         * Enables simplistic sampling resource leak detection which reports there is a leak or not,
         * at the cost of small overhead (default).
         */
        SIMPLE,
        /**
         * Enables advanced sampling resource leak detection which reports where the leaked object was accessed
         * recently at the cost of high overhead.
         */
        ADVANCED,
        /**
         * Enables paranoid resource leak detection which reports where the leaked object was accessed recently,
         * at the cost of the highest possible overhead (for testing purposes only).
         */
        PARANOID
    }

    private static Level level;

    private static final InternalLogger logger = InternalLoggerFactory.getInstance(ResourceLeakDetector.class);

    static {
        final boolean disabled;
        if (SystemPropertyUtil.get("io.netty.noResourceLeakDetection") != null) {
            disabled = SystemPropertyUtil.getBoolean("io.netty.noResourceLeakDetection", false);
            logger.debug("-Dio.netty.noResourceLeakDetection: {}", disabled);
            logger.warn(
                    "-Dio.netty.noResourceLeakDetection is deprecated. Use '-D{}={}' instead.",
                    PROP_LEVEL, DEFAULT_LEVEL.name().toLowerCase());
        } else {
            disabled = false;
        }

        Level defaultLevel = disabled? Level.DISABLED : DEFAULT_LEVEL;
        String levelStr = SystemPropertyUtil.get(PROP_LEVEL, defaultLevel.name()).trim().toUpperCase();
        Level level = DEFAULT_LEVEL;
        for (Level l: EnumSet.allOf(Level.class)) {
            if (levelStr.equals(l.name()) || levelStr.equals(String.valueOf(l.ordinal()))) {
                level = l;
            }
        }

        ResourceLeakDetector.level = level;
        if (logger.isDebugEnabled()) {
            logger.debug("-D{}: {}", PROP_LEVEL, level.name().toLowerCase());
        }
    }

    private static final int DEFAULT_SAMPLING_INTERVAL = 113;

    /**
     * @deprecated Use {@link #setLevel(Level)} instead.
     */
    @Deprecated
    public static void setEnabled(boolean enabled) {
        setLevel(enabled? Level.SIMPLE : Level.DISABLED);
    }

    /**
     * Returns {@code true} if resource leak detection is enabled.
     */
    public static boolean isEnabled() {
        return getLevel().ordinal() > Level.DISABLED.ordinal();
    }

    /**
     * Sets the resource leak detection level.
     */
    public static void setLevel(Level level) {
        if (level == null) {
            throw new NullPointerException("level");
        }
        ResourceLeakDetector.level = level;
    }

    /**
     * Returns the current resource leak detection level.
     */
    public static Level getLevel() {
        return level;
    }

    /** the linked list of active resources */
    private final DefaultResourceLeak head = new DefaultResourceLeak(null);
    private final DefaultResourceLeak tail = new DefaultResourceLeak(null);

    private final ReferenceQueue refQueue = new ReferenceQueue();
    private final ConcurrentMap reportedLeaks = PlatformDependent.newConcurrentHashMap();

    private final String resourceType;
    private final int samplingInterval;
    private final long maxActive;
    private long active;
    private final AtomicBoolean loggedTooManyActive = new AtomicBoolean();

    private long leakCheckCnt;

    public ResourceLeakDetector(Class resourceType) {
        this(simpleClassName(resourceType));
    }

    public ResourceLeakDetector(String resourceType) {
        this(resourceType, DEFAULT_SAMPLING_INTERVAL, Long.MAX_VALUE);
    }

    public ResourceLeakDetector(Class resourceType, int samplingInterval, long maxActive) {
        this(simpleClassName(resourceType), samplingInterval, maxActive);
    }

    public ResourceLeakDetector(String resourceType, int samplingInterval, long maxActive) {
        if (resourceType == null) {
            throw new NullPointerException("resourceType");
        }
        if (samplingInterval <= 0) {
            throw new IllegalArgumentException("samplingInterval: " + samplingInterval + " (expected: 1+)");
        }
        if (maxActive <= 0) {
            throw new IllegalArgumentException("maxActive: " + maxActive + " (expected: 1+)");
        }

        this.resourceType = resourceType;
        this.samplingInterval = samplingInterval;
        this.maxActive = maxActive;

        head.next = tail;
        tail.prev = head;
    }

    /**
     * Creates a new {@link ResourceLeak} which is expected to be closed via {@link ResourceLeak#close()} when the
     * related resource is deallocated.
     *
     * @return the {@link ResourceLeak} or {@code null}
     */
    public ResourceLeak open(T obj) {
        Level level = ResourceLeakDetector.level;
        if (level == Level.DISABLED) {
            return null;
        }

        if (level.ordinal() < Level.PARANOID.ordinal()) {
            if (leakCheckCnt ++ % samplingInterval == 0) {
                reportLeak(level);
                return new DefaultResourceLeak(obj);
            } else {
                return null;
            }
        } else {
            reportLeak(level);
            return new DefaultResourceLeak(obj);
        }
    }

    private void reportLeak(Level level) {
        if (!logger.isErrorEnabled()) {
            for (;;) {
                @SuppressWarnings("unchecked")
                DefaultResourceLeak ref = (DefaultResourceLeak) refQueue.poll();
                if (ref == null) {
                    break;
                }
                ref.close();
            }
            return;
        }

        // Report too many instances.
        int samplingInterval = level == Level.PARANOID? 1 : this.samplingInterval;
        if (active * samplingInterval > maxActive && loggedTooManyActive.compareAndSet(false, true)) {
            logger.error("LEAK: You are creating too many " + resourceType + " instances.  " +
                    resourceType + " is a shared resource that must be reused across the JVM," +
                    "so that only a few instances are created.");
        }

        // Detect and report previous leaks.
        for (;;) {
            @SuppressWarnings("unchecked")
            DefaultResourceLeak ref = (DefaultResourceLeak) refQueue.poll();
            if (ref == null) {
                break;
            }

            ref.clear();

            if (!ref.close()) {
                continue;
            }

            String records = ref.toString();
            if (reportedLeaks.putIfAbsent(records, Boolean.TRUE) == null) {
                if (records.isEmpty()) {
                    logger.error("LEAK: {}.release() was not called before it's garbage-collected. " +
                            "Enable advanced leak reporting to find out where the leak occurred. " +
                            "To enable advanced leak reporting, " +
                            "specify the JVM option '-D{}={}' or call {}.setLevel() " +
                            "See http://netty.io/wiki/reference-counted-objects.html for more information.",
                            resourceType, PROP_LEVEL, Level.ADVANCED.name().toLowerCase(), simpleClassName(this));
                } else {
                    logger.error(
                            "LEAK: {}.release() was not called before it's garbage-collected. " +
                            "See http://netty.io/wiki/reference-counted-objects.html for more information.{}",
                            resourceType, records);
                }
            }
        }
    }

    private final class DefaultResourceLeak extends PhantomReference implements ResourceLeak {

        private static final int MAX_RECORDS = 4;

        private final String creationRecord;
        private final Deque lastRecords = new ArrayDeque();
        private final AtomicBoolean freed;
        private DefaultResourceLeak prev;
        private DefaultResourceLeak next;

        DefaultResourceLeak(Object referent) {
            super(referent, referent != null? refQueue : null);

            if (referent != null) {
                Level level = getLevel();
                if (level.ordinal() >= Level.ADVANCED.ordinal()) {
                    creationRecord = newRecord(3);
                } else {
                    creationRecord = null;
                }

                // TODO: Use CAS to update the list.
                synchronized (head) {
                    prev = head;
                    next = head.next;
                    head.next.prev = this;
                    head.next = this;
                    active ++;
                }
                freed = new AtomicBoolean();
            } else {
                creationRecord = null;
                freed = new AtomicBoolean(true);
            }
        }

        @Override
        public void record() {
            if (creationRecord != null) {
                String value = newRecord(2);

                synchronized (lastRecords) {
                    int size = lastRecords.size();
                    if (size == 0 || !lastRecords.getLast().equals(value)) {
                        lastRecords.add(value);
                    }
                    if (size > MAX_RECORDS) {
                        lastRecords.removeFirst();
                    }
                }
            }
        }

        @Override
        public boolean close() {
            if (freed.compareAndSet(false, true)) {
                synchronized (head) {
                    active --;
                    prev.next = next;
                    next.prev = prev;
                    prev = null;
                    next = null;
                }
                return true;
            }
            return false;
        }

        @Override
        public String toString() {
            if (creationRecord == null) {
                return "";
            }

            Object[] array;
            synchronized (lastRecords) {
                array = lastRecords.toArray();
            }

            StringBuilder buf = new StringBuilder(16384)
                .append(NEWLINE)
                .append("Recent access records: ")
                .append(array.length)
                .append(NEWLINE);

            if (array.length > 0) {
                for (int i = array.length - 1; i >= 0; i --) {
                    buf.append('#')
                       .append(i + 1)
                       .append(':')
                       .append(NEWLINE)
                       .append(array[i]);
                }
            }

            buf.append("Created at:")
               .append(NEWLINE)
               .append(creationRecord);

            buf.setLength(buf.length() - NEWLINE.length());
            return buf.toString();
        }
    }

    private static final String[] STACK_TRACE_ELEMENT_EXCLUSIONS = {
            "io.netty.buffer.AbstractByteBufAllocator.toLeakAwareBuffer(",
    };

    static String newRecord(int recordsToSkip) {
        StringBuilder buf = new StringBuilder(4096);
        StackTraceElement[] array = new Throwable().getStackTrace();
        for (StackTraceElement e: array) {
            if (recordsToSkip > 0) {
                recordsToSkip --;
            } else {
                String estr = e.toString();

                // Strip the noisy stack trace elements.
                boolean excluded = false;
                for (String exclusion: STACK_TRACE_ELEMENT_EXCLUSIONS) {
                    if (estr.startsWith(exclusion)) {
                        excluded = true;
                        break;
                    }
                }

                if (!excluded) {
                    buf.append('\t');
                    buf.append(estr);
                    buf.append(NEWLINE);
                }
            }
        }

        return buf.toString();
    }
}
    
    
    
    

    




    
    
    © 2015 - 2025 Weber Informatics LLC | Privacy Policy