1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
|
// 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 com.yahoo.yolean.Exceptions;
import org.apache.http.client.HttpClient;
import org.apache.http.client.methods.HttpGet;
import org.apache.http.impl.client.BasicResponseHandler;
import java.io.IOException;
import java.time.Clock;
import java.time.Duration;
import java.time.Instant;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.logging.Logger;
import static com.yahoo.log.LogLevel.DEBUG;
import static java.util.Collections.emptyList;
/**
* 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());
static final Duration METRICS_TTL = Duration.ofSeconds(30);
final Node node;
private final HttpClient httpClient;
private final Clock clock;
private final Map<ConsumerId, Snapshot> snapshots = new HashMap<>();
private long snapshotsRetrieved = 0;
NodeMetricsClient(HttpClient httpClient, Node node, Clock clock) {
this.httpClient = httpClient;
this.node = node;
this.clock = clock;
}
public List<MetricsPacket.Builder> getMetrics(ConsumerId consumer) {
var currentSnapshot = snapshots.get(consumer);
if (currentSnapshot == null || currentSnapshot.isStale(clock) || currentSnapshot.metrics.isEmpty()) {
Snapshot snapshot = retrieveMetrics(consumer);
snapshots.put(consumer, snapshot);
return snapshot.metrics;
} else {
return snapshots.get(consumer).metrics;
}
}
private Snapshot retrieveMetrics(ConsumerId consumer) {
String metricsUri = node.metricsUri(consumer).toString();
log.log(DEBUG, () -> "Retrieving metrics from host " + metricsUri);
try {
String metricsJson = httpClient.execute(new HttpGet(metricsUri), new BasicResponseHandler());
var newMetrics = GenericJsonUtil.toMetricsPackets(metricsJson);
snapshotsRetrieved ++;
log.log(DEBUG, () -> "Successfully retrieved " + newMetrics.size() + " metrics packets from " + metricsUri);
return new Snapshot(Instant.now(clock), newMetrics);
} catch (IOException e) {
log.warning("Unable to retrieve metrics from " + metricsUri + ": " + Exceptions.toMessageString(e));
return new Snapshot(Instant.now(clock), emptyList());
}
}
long snapshotsRetrieved() {
return snapshotsRetrieved;
}
/**
* Convenience class for storing a metrics snapshot with its timestamp.
*/
static class Snapshot {
final Instant timestamp;
final List<MetricsPacket.Builder> metrics;
Snapshot(Instant timestamp, List<MetricsPacket.Builder> metrics) {
this.timestamp = timestamp;
this.metrics = metrics;
}
boolean isStale(Clock clock) {
return Instant.now(clock).isAfter(timestamp.plus(METRICS_TTL));
}
}
}
|
