com.wavefront.agent.histogram.HistogramUtils Maven / Gradle / Ivy
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package com.wavefront.agent.histogram;
import com.google.common.base.Preconditions;
import com.tdunning.math.stats.AgentDigest;
import com.tdunning.math.stats.TDigest;
import com.yammer.metrics.Metrics;
import com.yammer.metrics.core.Histogram;
import com.yammer.metrics.core.MetricName;
import java.nio.charset.StandardCharsets;
import java.util.List;
import java.util.Map;
import java.util.stream.Collectors;
import javax.annotation.Nonnull;
import javax.annotation.Nullable;
import net.openhft.chronicle.bytes.Bytes;
import net.openhft.chronicle.core.io.IORuntimeException;
import net.openhft.chronicle.core.util.ReadResolvable;
import net.openhft.chronicle.hash.serialization.BytesReader;
import net.openhft.chronicle.hash.serialization.BytesWriter;
import net.openhft.chronicle.wire.WireIn;
import net.openhft.chronicle.wire.WireOut;
import wavefront.report.ReportPoint;
/**
* Helpers around histograms
*
* @author Tim Schmidt ([email protected]).
*/
public final class HistogramUtils {
private HistogramUtils() {
// Not instantiable
}
/**
* Generates a {@link HistogramKey} according a prototype {@link ReportPoint} and {@link
* Granularity}.
*/
public static HistogramKey makeKey(ReportPoint point, Granularity granularity) {
Preconditions.checkNotNull(point);
Preconditions.checkNotNull(granularity);
String[] annotations = null;
if (point.getAnnotations() != null) {
List> keyOrderedTags =
point.getAnnotations().entrySet().stream()
.sorted(Map.Entry.comparingByKey())
.collect(Collectors.toList());
annotations = new String[keyOrderedTags.size() * 2];
for (int i = 0; i < keyOrderedTags.size(); ++i) {
annotations[2 * i] = keyOrderedTags.get(i).getKey();
annotations[(2 * i) + 1] = keyOrderedTags.get(i).getValue();
}
}
return new HistogramKey(
(byte) granularity.ordinal(),
granularity.getBinId(point.getTimestamp()),
point.getMetric(),
point.getHost(),
annotations);
}
/**
* Creates a {@link ReportPoint} from a {@link HistogramKey} - {@link AgentDigest} pair
*
* @param histogramKey the key, defining metric, source, annotations, duration and start-time
* @param agentDigest the digest defining the centroids
* @return the corresponding point
*/
public static ReportPoint pointFromKeyAndDigest(
HistogramKey histogramKey, AgentDigest agentDigest) {
return ReportPoint.newBuilder()
.setTimestamp(histogramKey.getBinTimeMillis())
.setMetric(histogramKey.getMetric())
.setHost(histogramKey.getSource())
.setAnnotations(histogramKey.getTagsAsMap())
.setTable("dummy")
.setValue(agentDigest.toHistogram((int) histogramKey.getBinDurationInMillis()))
.build();
}
/**
* Convert granularity to string. If null, we assume we are dealing with "distribution" port.
*
* @param granularity granularity
* @return string representation
*/
public static String granularityToString(@Nullable Granularity granularity) {
return granularity == null ? "distribution" : granularity.toString();
}
/**
* Merges a histogram into a TDigest
*
* @param target target TDigest
* @param source histogram to merge
*/
public static void mergeHistogram(final TDigest target, final wavefront.report.Histogram source) {
List means = source.getBins();
List counts = source.getCounts();
if (means != null && counts != null) {
int len = Math.min(means.size(), counts.size());
for (int i = 0; i < len; ++i) {
Integer count = counts.get(i);
Double mean = means.get(i);
if (count != null && count > 0 && mean != null && Double.isFinite(mean)) {
target.add(mean, count);
}
}
}
}
/**
* (For now, a rather trivial) encoding of {@link HistogramKey} the form short length and bytes
*
* Consider using chronicle-values or making this stateful with a local byte[] / Stringbuffers
* to be a little more efficient about encodings.
*/
public static class HistogramKeyMarshaller
implements BytesReader,
BytesWriter,
ReadResolvable {
private static final HistogramKeyMarshaller INSTANCE = new HistogramKeyMarshaller();
private static final Histogram accumulatorKeySizes =
Metrics.newHistogram(new MetricName("histogram", "", "accumulatorKeySize"));
private HistogramKeyMarshaller() {
// Private Singleton
}
public static HistogramKeyMarshaller get() {
return INSTANCE;
}
@Nonnull
@Override
public HistogramKeyMarshaller readResolve() {
return INSTANCE;
}
private static void writeString(Bytes out, String s) {
Preconditions.checkArgument(
s == null || s.length() <= Short.MAX_VALUE, "String too long (more than 32K)");
byte[] bytes = s == null ? new byte[0] : s.getBytes(StandardCharsets.UTF_8);
out.writeShort((short) bytes.length);
out.write(bytes);
}
private static String readString(Bytes in) {
byte[] bytes = new byte[in.readShort()];
in.read(bytes);
return new String(bytes);
}
@Override
public void readMarshallable(@Nonnull WireIn wire) throws IORuntimeException {
// ignore, stateless
}
@Override
public void writeMarshallable(@Nonnull WireOut wire) {
// ignore, stateless
}
@Nonnull
@Override
public HistogramKey read(Bytes in, @Nullable HistogramKey using) {
if (using == null) {
using = new HistogramKey();
}
using.setGranularityOrdinal(in.readByte());
using.setBinId(in.readInt());
using.setMetric(readString(in));
using.setSource(readString(in));
int numTags = in.readShort();
if (numTags > 0) {
final String[] tags = new String[numTags];
for (int i = 0; i < numTags; ++i) {
tags[i] = readString(in);
}
using.setTags(tags);
}
return using;
}
@Override
public void write(Bytes out, @Nonnull HistogramKey toWrite) {
int accumulatorKeySize = 5;
out.writeByte(toWrite.getGranularityOrdinal());
out.writeInt(toWrite.getBinId());
accumulatorKeySize += 2 + toWrite.getMetric().length();
writeString(out, toWrite.getMetric());
accumulatorKeySize += 2 + (toWrite.getSource() == null ? 0 : toWrite.getSource().length());
writeString(out, toWrite.getSource());
short numTags = toWrite.getTags() == null ? 0 : (short) toWrite.getTags().length;
accumulatorKeySize += 2;
out.writeShort(numTags);
for (short i = 0; i < numTags; ++i) {
final String tag = toWrite.getTags()[i];
accumulatorKeySize += 2 + (tag == null ? 0 : tag.length());
writeString(out, tag);
}
accumulatorKeySizes.update(accumulatorKeySize);
}
}
}