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// Copyright 2020 Oath Inc. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
package ai.vespa.metricsproxy.http.application;
import ai.vespa.metricsproxy.metric.model.ConsumerId;
import ai.vespa.metricsproxy.metric.model.MetricsPacket;
import ai.vespa.metricsproxy.metric.model.json.GenericJsonUtil;
import ai.vespa.metricsproxy.metric.model.processing.MetricsProcessor;
import com.yahoo.yolean.Exceptions;
import org.apache.hc.client5.http.classic.HttpClient;
import org.apache.hc.client5.http.classic.methods.HttpGet;
import org.apache.hc.client5.http.impl.classic.BasicHttpClientResponseHandler;
import java.io.IOException;
import java.time.Clock;
import java.time.Duration;
import java.time.Instant;
import java.util.List;
import java.util.Map;
import java.util.concurrent.ConcurrentHashMap;
import java.util.concurrent.atomic.AtomicLong;
import java.util.logging.Logger;
import static ai.vespa.metricsproxy.metric.model.processing.MetricsProcessor.applyProcessors;
import static java.util.Collections.emptyList;
import static java.util.logging.Level.FINE;
import static java.util.stream.Collectors.toList;
/**
* Retrieves metrics from a single Vespa node over http. To avoid unnecessary load on metrics
* proxies, a cached snapshot per consumer is retained and served for a fixed TTL period.
* Upon failure to retrieve metrics, an empty snapshot is cached.
*
* This class assumes that the consumer id is a valid and existing one, which is already
* ensured by the {@link ApplicationMetricsHandler}.
*
* @author gjoranv
*/
public class NodeMetricsClient {
private static final Logger log = Logger.getLogger(NodeMetricsClient.class.getName());
private static final int MAX_DIMENSIONS = 10;
final Node node;
private final HttpClient httpClient;
private final Clock clock;
private final Map<ConsumerId, Snapshot> snapshots = new ConcurrentHashMap<>();
private AtomicLong snapshotsRetrieved = new AtomicLong();
NodeMetricsClient(HttpClient httpClient, Node node, Clock clock) {
this.httpClient = httpClient;
this.node = node;
this.clock = clock;
}
List<MetricsPacket> getMetrics(ConsumerId consumer) {
var snapshot = snapshots.get(consumer);
return (snapshot != null) ? snapshot.metrics : List.of();
}
boolean updateSnapshots(ConsumerId consumer, Duration ttl) {
var snapshot = snapshots.get(consumer);
if ((snapshot) != null && clock.instant().isBefore(snapshot.timestamp.plus(ttl))) return true;
snapshot = retrieveMetrics(consumer);
snapshots.put(consumer, snapshot);
return ! snapshot.metrics.isEmpty();
}
private Snapshot retrieveMetrics(ConsumerId consumer) {
String metricsUri = node.metricsUri(consumer).toString();
log.log(FINE, () -> "Retrieving metrics from host " + metricsUri);
try {
String metricsJson = httpClient.execute(new HttpGet(metricsUri), new BasicHttpClientResponseHandler());
var metricsBuilders = GenericJsonUtil.toMetricsPackets(metricsJson);
var metrics = processAndBuild(metricsBuilders,
new ServiceIdDimensionProcessor(),
new ClusterIdDimensionProcessor(),
new PublicDimensionsProcessor(MAX_DIMENSIONS));
snapshotsRetrieved.incrementAndGet();
log.log(FINE, () -> "Successfully retrieved " + metrics.size() + " metrics packets from " + metricsUri);
return new Snapshot(Instant.now(clock), metrics);
} catch (IOException e) {
log.warning("Unable to retrieve metrics from " + metricsUri + ": " + Exceptions.toMessageString(e));
return new Snapshot(Instant.now(clock), emptyList());
}
}
private static List<MetricsPacket> processAndBuild(List<MetricsPacket.Builder> builders,
MetricsProcessor... processors) {
return builders.stream()
.map(builder -> applyProcessors(builder, processors))
.map(MetricsPacket.Builder::build)
.collect(toList());
}
long snapshotsRetrieved() {
return snapshotsRetrieved.get();
}
/**
* Convenience class for storing a metrics snapshot with its timestamp.
*/
static class Snapshot {
final Instant timestamp;
final List<MetricsPacket> metrics;
Snapshot(Instant timestamp, List<MetricsPacket> metrics) {
this.timestamp = timestamp;
this.metrics = metrics;
}
}
}
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