聊聊flink的MetricQueryServiceGateway

本文主要研究一下flink的MetricQueryServiceGateway

MetricQueryServiceGateway

flink-1.7.2/flink-runtime/src/main/java/org/apache/flink/runtime/webmonitor/retriever/MetricQueryServiceGateway.java

public interface MetricQueryServiceGateway {

CompletableFuture<MetricDumpSerialization.MetricSerializationResult> queryMetrics(Time timeout);

String getAddress();
}
  • MetricQueryServiceGateway定义了两个方法,一个是queryMetrics,一个是getAddress;它有一个实现类为AkkaQueryServiceGateway

AkkaQueryServiceGateway

flink-1.7.2/flink-runtime/src/main/java/org/apache/flink/runtime/webmonitor/retriever/impl/AkkaQueryServiceGateway.java

public class AkkaQueryServiceGateway implements MetricQueryServiceGateway {

private final ActorRef queryServiceActorRef;

public AkkaQueryServiceGateway(ActorRef queryServiceActorRef) {
this.queryServiceActorRef = Preconditions.checkNotNull(queryServiceActorRef);
}

@Override
public CompletableFuture<MetricDumpSerialization.MetricSerializationResult> queryMetrics(Time timeout) {
return FutureUtils.toJava(
Patterns.ask(queryServiceActorRef, MetricQueryService.getCreateDump(), timeout.toMilliseconds())
.mapTo(ClassTag$.MODULE$.apply(MetricDumpSerialization.MetricSerializationResult.class))
);
}

@Override
public String getAddress() {
return queryServiceActorRef.path().toString();
}
}
  • AkkaQueryServiceGateway实现了MetricQueryServiceGateway接口,它的构造器要求传入queryServiceActorRef;queryMetrics方法ask的消息类型为MetricQueryService.CreateDump;getAddress方法返回的是queryServiceActorRef.path()

MetricQueryService

flink-1.7.2/flink-runtime/src/main/java/org/apache/flink/runtime/metrics/dump/MetricQueryService.java

public class MetricQueryService extends UntypedActor {
private static final Logger LOG = LoggerFactory.getLogger(MetricQueryService.class);

public static final String METRIC_QUERY_SERVICE_NAME = "MetricQueryService";
private static final String SIZE_EXCEEDED_LOG_TEMPLATE =  "{} will not be reported as the metric dump would exceed the maximum size of {} bytes.";

private static final CharacterFilter FILTER = new CharacterFilter() {
@Override
public String filterCharacters(String input) {
return replaceInvalidChars(input);
}
};

private final MetricDumpSerializer serializer = new MetricDumpSerializer();

private final Map<Gauge<?>, Tuple2<QueryScopeInfo, String>> gauges = new HashMap<>();
private final Map<Counter, Tuple2<QueryScopeInfo, String>> counters = new HashMap<>();
private final Map<Histogram, Tuple2<QueryScopeInfo, String>> histograms = new HashMap<>();
private final Map<Meter, Tuple2<QueryScopeInfo, String>> meters = new HashMap<>();

private final long messageSizeLimit;

//......

@Override
public void onReceive(Object message) {
try {
if (message instanceof AddMetric) {
AddMetric added = (AddMetric) message;

String metricName = added.metricName;
Metric metric = added.metric;
AbstractMetricGroup group = added.group;

QueryScopeInfo info = group.getQueryServiceMetricInfo(FILTER);

if (metric instanceof Counter) {
counters.put((Counter) metric, new Tuple2<>(info, FILTER.filterCharacters(metricName)));
} else if (metric instanceof Gauge) {
gauges.put((Gauge<?>) metric, new Tuple2<>(info, FILTER.filterCharacters(metricName)));
} else if (metric instanceof Histogram) {
histograms.put((Histogram) metric, new Tuple2<>(info, FILTER.filterCharacters(metricName)));
} else if (metric instanceof Meter) {
meters.put((Meter) metric, new Tuple2<>(info, FILTER.filterCharacters(metricName)));
}
} else if (message instanceof RemoveMetric) {
Metric metric = (((RemoveMetric) message).metric);
if (metric instanceof Counter) {
this.counters.remove(metric);
} else if (metric instanceof Gauge) {
this.gauges.remove(metric);
} else if (metric instanceof Histogram) {
this.histograms.remove(metric);
} else if (metric instanceof Meter) {
this.meters.remove(metric);
}
} else if (message instanceof CreateDump) {
MetricDumpSerialization.MetricSerializationResult dump = serializer.serialize(counters, gauges, histograms, meters);

dump = enforceSizeLimit(dump);

getSender().tell(dump, getSelf());
} else {
LOG.warn("MetricQueryServiceActor received an invalid message. " + message.toString());
getSender().tell(new Status.Failure(new IOException("MetricQueryServiceActor received an invalid message. " + message.toString())), getSelf());
}
} catch (Exception e) {
LOG.warn("An exception occurred while processing a message.", e);
}
}

public static Object getCreateDump() {
return CreateDump.INSTANCE;
}

private static class CreateDump implements Serializable {
private static final CreateDump INSTANCE = new CreateDump();
}
//......
}
  • MetricQueryService继承了UntypedActor,它的onReceive方法判断message类型,如果为CreateDump的话,则调用MetricDumpSerialization.MetricDumpSerializer.serialize(counters, gauges, histograms, meters)方法来序列化metrics得到MetricDumpSerialization.MetricSerializationResult,然后使用getSender().tell(dump, getSelf())返回数据

MetricDumpSerialization

flink-1.7.2/flink-runtime/src/main/java/org/apache/flink/runtime/metrics/dump/MetricDumpSerialization.java

public class MetricDumpSerialization {
//......

public static class MetricSerializationResult implements Serializable {

private static final long serialVersionUID = 6928770855951536906L;

public final byte[] serializedCounters;
public final byte[] serializedGauges;
public final byte[] serializedMeters;
public final byte[] serializedHistograms;

public final int numCounters;
public final int numGauges;
public final int numMeters;
public final int numHistograms;

public MetricSerializationResult(
byte[] serializedCounters,
byte[] serializedGauges,
byte[] serializedMeters,
byte[] serializedHistograms,
int numCounters,
int numGauges,
int numMeters,
int numHistograms) {

Preconditions.checkNotNull(serializedCounters);
Preconditions.checkNotNull(serializedGauges);
Preconditions.checkNotNull(serializedMeters);
Preconditions.checkNotNull(serializedHistograms);
Preconditions.checkArgument(numCounters >= 0);
Preconditions.checkArgument(numGauges >= 0);
Preconditions.checkArgument(numMeters >= 0);
Preconditions.checkArgument(numHistograms >= 0);
this.serializedCounters = serializedCounters;
this.serializedGauges = serializedGauges;
this.serializedMeters = serializedMeters;
this.serializedHistograms = serializedHistograms;
this.numCounters = numCounters;
this.numGauges = numGauges;
this.numMeters = numMeters;
this.numHistograms = numHistograms;
}
}

public static class MetricDumpSerializer {

private DataOutputSerializer countersBuffer = new DataOutputSerializer(1024 * 8);
private DataOutputSerializer gaugesBuffer = new DataOutputSerializer(1024 * 8);
private DataOutputSerializer metersBuffer = new DataOutputSerializer(1024 * 8);
private DataOutputSerializer histogramsBuffer = new DataOutputSerializer(1024 * 8);

public MetricSerializationResult serialize(
Map<Counter, Tuple2<QueryScopeInfo, String>> counters,
Map<Gauge<?>, Tuple2<QueryScopeInfo, String>> gauges,
Map<Histogram, Tuple2<QueryScopeInfo, String>> histograms,
Map<Meter, Tuple2<QueryScopeInfo, String>> meters) {

countersBuffer.clear();
int numCounters = 0;
for (Map.Entry<Counter, Tuple2<QueryScopeInfo, String>> entry : counters.entrySet()) {
try {
serializeCounter(countersBuffer, entry.getValue().f0, entry.getValue().f1, entry.getKey());
numCounters++;
} catch (Exception e) {
LOG.debug("Failed to serialize counter.", e);
}
}

gaugesBuffer.clear();
int numGauges = 0;
for (Map.Entry<Gauge<?>, Tuple2<QueryScopeInfo, String>> entry : gauges.entrySet()) {
try {
serializeGauge(gaugesBuffer, entry.getValue().f0, entry.getValue().f1, entry.getKey());
numGauges++;
} catch (Exception e) {
LOG.debug("Failed to serialize gauge.", e);
}
}

histogramsBuffer.clear();
int numHistograms = 0;
for (Map.Entry<Histogram, Tuple2<QueryScopeInfo, String>> entry : histograms.entrySet()) {
try {
serializeHistogram(histogramsBuffer, entry.getValue().f0, entry.getValue().f1, entry.getKey());
numHistograms++;
} catch (Exception e) {
LOG.debug("Failed to serialize histogram.", e);
}
}

metersBuffer.clear();
int numMeters = 0;
for (Map.Entry<Meter, Tuple2<QueryScopeInfo, String>> entry : meters.entrySet()) {
try {
serializeMeter(metersBuffer, entry.getValue().f0, entry.getValue().f1, entry.getKey());
numMeters++;
} catch (Exception e) {
LOG.debug("Failed to serialize meter.", e);
}
}

return new MetricSerializationResult(
countersBuffer.getCopyOfBuffer(),
gaugesBuffer.getCopyOfBuffer(),
metersBuffer.getCopyOfBuffer(),
histogramsBuffer.getCopyOfBuffer(),
numCounters,
numGauges,
numMeters,
numHistograms);
}

public void close() {
countersBuffer = null;
gaugesBuffer = null;
metersBuffer = null;
histogramsBuffer = null;
}
}

//......
}
  • MetricDumpSerialization有几个静态类分别是MetricSerializationResult、MetricDumpSerializer、MetricDumpDeserializer;MetricDumpSerializer提供了serialize方法用于将counters、gauges、histograms、meters指标序列化为MetricSerializationResult

小结

  • MetricQueryServiceGateway定义了两个方法,一个是queryMetrics,一个是getAddress;它有一个实现类为AkkaQueryServiceGateway
  • AkkaQueryServiceGateway实现了MetricQueryServiceGateway接口,它的构造器要求传入queryServiceActorRef;queryMetrics方法ask的消息类型为MetricQueryService.CreateDump;getAddress方法返回的是queryServiceActorRef.path()
  • MetricQueryService继承了UntypedActor,它的onReceive方法判断message类型,如果为CreateDump的话,则调用MetricDumpSerialization.MetricDumpSerializer.serialize(counters, gauges, histograms, meters)方法来序列化metrics得到MetricDumpSerialization.MetricSerializationResult,然后使用getSender().tell(dump, getSelf())返回数据;MetricDumpSerialization有几个静态类分别是MetricSerializationResult、MetricDumpSerializer、MetricDumpDeserializer;MetricDumpSerializer提供了serialize方法用于将counters、gauges、histograms、meters指标序列化为MetricSerializationResult

doc

  • MetricQueryServiceGateway

本文分享自微信公众号 - 码匠的流水账(geek_luandun)

原文出处及转载信息见文内详细说明,如有侵权,请联系 yunjia_community@tencent.com 删除。

原始发表时间:2019-03-17

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