AsyncTimerExec.java
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package org.apache.hc.client5.http.observation.interceptors;
import java.io.IOException;
import java.util.ArrayList;
import java.util.List;
import java.util.concurrent.TimeUnit;
import java.util.concurrent.atomic.AtomicInteger;
import java.util.concurrent.atomic.AtomicReference;
import io.micrometer.core.instrument.Counter;
import io.micrometer.core.instrument.Gauge;
import io.micrometer.core.instrument.MeterRegistry;
import io.micrometer.core.instrument.Tag;
import io.micrometer.core.instrument.Timer;
import org.apache.hc.client5.http.async.AsyncExecCallback;
import org.apache.hc.client5.http.async.AsyncExecChain;
import org.apache.hc.client5.http.async.AsyncExecChainHandler;
import org.apache.hc.client5.http.observation.MetricConfig;
import org.apache.hc.client5.http.observation.ObservingOptions;
import org.apache.hc.core5.http.EntityDetails;
import org.apache.hc.core5.http.HttpException;
import org.apache.hc.core5.http.HttpRequest;
import org.apache.hc.core5.http.HttpResponse;
import org.apache.hc.core5.util.Args;
/**
* Records request latency and response counters for <b>asynchronous</b> clients.
* <p>
* Meters:
* <ul>
* <li>{@code <prefix>.request} (timer) ��� latency, uses {@link MetricConfig#slo} and {@link MetricConfig#percentiles}</li>
* <li>{@code <prefix>.response} (counter) ��� result count</li>
* <li>{@code <prefix>.inflight} (gauge, kind=async) ��� in-flight request count</li>
* </ul>
* Tags: {@code method}, {@code status}, and when {@link ObservingOptions.TagLevel#EXTENDED}
* also {@code protocol}, {@code target}. Any {@link MetricConfig#commonTags} are appended.
*
* @since 5.6
*/
public final class AsyncTimerExec implements AsyncExecChainHandler {
private final MeterRegistry registry;
private final ObservingOptions opts;
private final MetricConfig mc;
private final AtomicInteger inflight = new AtomicInteger();
public AsyncTimerExec(final MeterRegistry reg, final ObservingOptions opts, final MetricConfig mc) {
this.registry = Args.notNull(reg, "registry");
this.opts = Args.notNull(opts, "options");
this.mc = mc != null ? mc : MetricConfig.builder().build();
// Tag-aware guard: only register once per (name + tags)
if (registry.find(this.mc.prefix + ".inflight")
.tags("kind", "async")
.tags(this.mc.commonTags)
.gauge() == null) {
Gauge.builder(this.mc.prefix + ".inflight", inflight, AtomicInteger::doubleValue)
.tag("kind", "async")
.tags(this.mc.commonTags)
.register(registry);
}
}
@Override
public void execute(final HttpRequest request,
final org.apache.hc.core5.http.nio.AsyncEntityProducer entityProducer,
final AsyncExecChain.Scope scope,
final AsyncExecChain chain,
final AsyncExecCallback callback) throws HttpException, IOException {
if (!opts.spanSampling.test(request.getRequestUri())) {
chain.proceed(request, entityProducer, scope, callback);
return;
}
inflight.incrementAndGet();
final long start = System.nanoTime();
final AtomicReference<HttpResponse> respRef = new AtomicReference<HttpResponse>();
final AsyncExecCallback wrapped = new AsyncExecCallback() {
@Override
public org.apache.hc.core5.http.nio.AsyncDataConsumer handleResponse(
final HttpResponse response, final EntityDetails entityDetails) throws HttpException, IOException {
respRef.set(response);
return callback.handleResponse(response, entityDetails);
}
@Override
public void handleInformationResponse(final HttpResponse response) throws HttpException, IOException {
callback.handleInformationResponse(response);
}
@Override
public void completed() {
record();
callback.completed();
}
@Override
public void failed(final Exception cause) {
record();
callback.failed(cause);
}
private void record() {
try {
final long dur = System.nanoTime() - start;
final HttpResponse r = respRef.get();
final int status = r != null ? r.getCode() : 599;
final String protocol = scope.route.getTargetHost().getSchemeName();
final String target = scope.route.getTargetHost().getHostName();
final List<Tag> tags = buildTags(request.getMethod(), status, protocol, target, request.getRequestUri());
Timer.Builder tb = Timer.builder(mc.prefix + ".request")
.tags(tags)
.tags(mc.commonTags);
if (mc.slo != null) {
tb = tb.serviceLevelObjectives(mc.slo);
}
if (mc.percentiles != null && mc.percentiles.length > 0) {
tb = tb.publishPercentiles(mc.percentiles);
}
tb.register(registry).record(dur, TimeUnit.NANOSECONDS);
Counter.builder(mc.prefix + ".response")
.tags(tags)
.tags(mc.commonTags)
.register(registry)
.increment();
} finally {
inflight.decrementAndGet();
}
}
};
chain.proceed(request, entityProducer, scope, wrapped);
}
private List<Tag> buildTags(final String method,
final int status,
final String protocol,
final String target,
final String uri) {
final List<Tag> tags = new ArrayList<>(6);
tags.add(Tag.of("method", method));
tags.add(Tag.of("status", Integer.toString(status)));
if (opts.tagLevel == ObservingOptions.TagLevel.EXTENDED) {
tags.add(Tag.of("protocol", protocol));
tags.add(Tag.of("target", target));
}
// Note: async timer does not add "uri" even if perUriIo is true (that flag is for IO counters).
return opts.tagCustomizer.apply(tags, method, status, protocol, target, uri);
}
}