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// Copyright 2018 Yahoo Holdings. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
package com.yahoo.container.jdisc.metric;
import com.google.inject.Inject;
import com.yahoo.component.AbstractComponent;
import com.yahoo.jdisc.Metric;
import com.yahoo.jdisc.statistics.ContainerWatchdogMetrics;
import java.nio.file.DirectoryStream;
import java.nio.file.Files;
import java.nio.file.Path;
import java.nio.file.Paths;
import java.time.Clock;
import java.time.Duration;
import java.util.Timer;
import java.util.TimerTask;
/**
* Uses a timer to emit metrics
*
* @author bjorncs
* @author vegardh
*
*/
public class MetricUpdater extends AbstractComponent {
private static final String FREE_MEMORY_BYTES = "mem.heap.free";
private static final String USED_MEMORY_BYTES = "mem.heap.used";
private static final String TOTAL_MEMORY_BYTES = "mem.heap.total";
private static final String MEMORY_MAPPINGS_COUNT = "jdisc.memory_mappings";
private static final String OPEN_FILE_DESCRIPTORS = "jdisc.open_file_descriptors";
private final Scheduler scheduler;
@Inject
public MetricUpdater(Metric metric, ContainerWatchdogMetrics containerWatchdogMetrics) {
this(new TimerScheduler(), metric, containerWatchdogMetrics);
}
MetricUpdater(Scheduler scheduler, Metric metric, ContainerWatchdogMetrics containerWatchdogMetrics) {
this.scheduler = scheduler;
scheduler.schedule(new UpdaterTask(metric, containerWatchdogMetrics), Duration.ofSeconds(10));
}
@Override
public void deconstruct() {
scheduler.cancel();
}
// Note: Linux-specific
private static long count_mappings() {
long count = 0;
try {
Path p = Paths.get("/proc/self/maps");
if (!p.toFile().exists()) return 0; // E.g. MacOS
byte[] data = Files.readAllBytes(p);
for (byte b : data) {
if (b == '\n') {
++count;
}
}
} catch (Exception e) {
System.err.println("Could not read /proc/self/maps: " + e);
}
return count;
}
// Note: Linux-specific
private static long count_open_files() {
long count = 0;
try {
Path p = Paths.get("/proc/self/fd");
if (!p.toFile().exists()) return 0; // E.g. MacOS
try (DirectoryStream<Path> stream = Files.newDirectoryStream(p)) {
for (Path entry : stream) {
++count;
}
}
} catch (Exception e) {
System.err.println("Could not read /proc/self/fd: " + e);
}
return count;
}
private static class UpdaterTask implements Runnable {
private final Runtime runtime = Runtime.getRuntime();
private final Metric metric;
private final ContainerWatchdogMetrics containerWatchdogMetrics;
private final GarbageCollectionMetrics garbageCollectionMetrics;
public UpdaterTask(Metric metric, ContainerWatchdogMetrics containerWatchdogMetrics) {
this.metric = metric;
this.containerWatchdogMetrics = containerWatchdogMetrics;
this.garbageCollectionMetrics = new GarbageCollectionMetrics(Clock.systemUTC());
}
@SuppressWarnings("deprecation")
@Override
public void run() {
long freeMemory = runtime.freeMemory();
long totalMemory = runtime.totalMemory();
long usedMemory = totalMemory - freeMemory;
metric.set(FREE_MEMORY_BYTES, freeMemory, null);
metric.set(USED_MEMORY_BYTES, usedMemory, null);
metric.set(TOTAL_MEMORY_BYTES, totalMemory, null);
metric.set(MEMORY_MAPPINGS_COUNT, count_mappings(), null);
metric.set(OPEN_FILE_DESCRIPTORS, count_open_files(), null);
containerWatchdogMetrics.emitMetrics(metric);
garbageCollectionMetrics.emitMetrics(metric);
}
}
private static class TimerScheduler implements Scheduler {
private final Timer timer = new Timer();
@Override
public void schedule(Runnable runnable, Duration frequency) {
long frequencyMillis = frequency.toMillis();
timer.schedule(new TimerTask() {
@Override
public void run() {
runnable.run();
}
}, frequencyMillis, frequencyMillis) ;
}
@Override
public void cancel() {
timer.cancel();
}
}
interface Scheduler {
void schedule(Runnable runnable, Duration frequency);
void cancel();
}
}
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