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Caffeine instrumentation: add weighted size metric (#1251)
* Change caffeine_cache_eviction_weight from Gauge to Counter Signed-off-by: Jean Hominal <[email protected]> * Add caffeine_cache_weighted_size gauge metric to caffeine-instrumentation Signed-off-by: Jean Hominal <[email protected]> * Add Builder pattern for caffeine CacheMetricsCollector Signed-off-by: Jean Hominal <[email protected]> * Add option collectEvictionWeightAsCounter to collect caffeine_cache_eviction_weight as an incremental counter Signed-off-by: Jean Hominal <[email protected]> * Add option collectWeightedSize to enable collection of caffeine_cache_weighted_size Signed-off-by: Jean Hominal <[email protected]> --------- Signed-off-by: Jean Hominal <[email protected]>
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‎prometheus-metrics-instrumentation-caffeine/src/main/java/io/prometheus/metrics/instrumentation/caffeine/CacheMetricsCollector.java‎

Lines changed: 98 additions & 4 deletions
Original file line numberDiff line numberDiff line change
@@ -3,6 +3,7 @@
33
import com.github.benmanes.caffeine.cache.AsyncCache;
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import com.github.benmanes.caffeine.cache.Cache;
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import com.github.benmanes.caffeine.cache.LoadingCache;
6+
import com.github.benmanes.caffeine.cache.Policy;
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import com.github.benmanes.caffeine.cache.stats.CacheStats;
78
import io.prometheus.metrics.model.registry.MultiCollector;
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import io.prometheus.metrics.model.snapshots.CounterSnapshot;
@@ -14,8 +15,10 @@
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import java.util.Collections;
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import java.util.List;
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import java.util.Map;
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import java.util.Optional;
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import java.util.concurrent.ConcurrentHashMap;
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import java.util.concurrent.ConcurrentMap;
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import java.util.stream.Collectors;
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/**
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* Collect metrics from Caffeine's com.github.benmanes.caffeine.cache.Cache.
@@ -25,7 +28,7 @@
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* <pre>{@code
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* // Note that `recordStats()` is required to gather non-zero statistics
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* Cache<String, String> cache = Caffeine.newBuilder().recordStats().build();
28-
* CacheMetricsCollector cacheMetrics = new CacheMetricsCollector();
31+
* CacheMetricsCollector cacheMetrics = CacheMetricsCollector.builder().build();
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* PrometheusRegistry.defaultRegistry.register(cacheMetrics);
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* cacheMetrics.addCache("mycache", cache);
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*
@@ -63,6 +66,7 @@ public class CacheMetricsCollector implements MultiCollector {
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private static final String METRIC_NAME_CACHE_LOAD_FAILURE = "caffeine_cache_load_failure";
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private static final String METRIC_NAME_CACHE_LOADS = "caffeine_cache_loads";
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private static final String METRIC_NAME_CACHE_ESTIMATED_SIZE = "caffeine_cache_estimated_size";
69+
private static final String METRIC_NAME_CACHE_WEIGHTED_SIZE = "caffeine_cache_weighted_size";
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private static final String METRIC_NAME_CACHE_LOAD_DURATION_SECONDS =
6771
"caffeine_cache_load_duration_seconds";
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@@ -77,9 +81,38 @@ public class CacheMetricsCollector implements MultiCollector {
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METRIC_NAME_CACHE_LOAD_FAILURE,
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METRIC_NAME_CACHE_LOADS,
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METRIC_NAME_CACHE_ESTIMATED_SIZE,
84+
METRIC_NAME_CACHE_WEIGHTED_SIZE,
8085
METRIC_NAME_CACHE_LOAD_DURATION_SECONDS));
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8287
protected final ConcurrentMap<String, Cache<?, ?>> children = new ConcurrentHashMap<>();
88+
private final boolean collectEvictionWeightAsCounter;
89+
private final boolean collectWeightedSize;
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91+
/**
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* Instantiates a {@link CacheMetricsCollector}, with the legacy parameters.
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*
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* <p>The use of this constructor is discouraged, in favor of a Builder pattern {@link #builder()}
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*
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* <p>Note that the {@link #builder()} API has different default values than this deprecated
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* constructor.
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*/
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@Deprecated
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public CacheMetricsCollector() {
101+
this(false, false);
102+
}
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/**
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* Instantiate a {@link CacheMetricsCollector}
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*
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* @param collectEvictionWeightAsCounter If true, {@code caffeine_cache_eviction_weight} will be
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* observed as an incrementing counter instead of a gauge.
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* @param collectWeightedSize If true, {@code caffeine_cache_weighted_size} will be observed.
110+
*/
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protected CacheMetricsCollector(
112+
boolean collectEvictionWeightAsCounter, boolean collectWeightedSize) {
113+
this.collectEvictionWeightAsCounter = collectEvictionWeightAsCounter;
114+
this.collectWeightedSize = collectWeightedSize;
115+
}
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/**
85118
* Add or replace the cache with the given name.
@@ -146,10 +179,14 @@ public MetricSnapshots collect() {
146179
.name(METRIC_NAME_CACHE_EVICTION)
147180
.help("Cache eviction totals, doesn't include manually removed entries");
148181

149-
final GaugeSnapshot.Builder cacheEvictionWeight =
182+
final CounterSnapshot.Builder cacheEvictionWeight =
183+
CounterSnapshot.builder()
184+
.name(METRIC_NAME_CACHE_EVICTION_WEIGHT)
185+
.help("Weight of evicted cache entries, doesn't include manually removed entries");
186+
final GaugeSnapshot.Builder cacheEvictionWeightLegacyGauge =
150187
GaugeSnapshot.builder()
151188
.name(METRIC_NAME_CACHE_EVICTION_WEIGHT)
152-
.help("Cache eviction weight");
189+
.help("Weight of evicted cache entries, doesn't include manually removed entries");
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154191
final CounterSnapshot.Builder cacheLoadFailure =
155192
CounterSnapshot.builder().name(METRIC_NAME_CACHE_LOAD_FAILURE).help("Cache load failures");
@@ -162,6 +199,11 @@ public MetricSnapshots collect() {
162199
final GaugeSnapshot.Builder cacheSize =
163200
GaugeSnapshot.builder().name(METRIC_NAME_CACHE_ESTIMATED_SIZE).help("Estimated cache size");
164201

202+
final GaugeSnapshot.Builder cacheWeightedSize =
203+
GaugeSnapshot.builder()
204+
.name(METRIC_NAME_CACHE_WEIGHTED_SIZE)
205+
.help("Approximate accumulated weight of cache entries");
206+
165207
final SummarySnapshot.Builder cacheLoadSummary =
166208
SummarySnapshot.builder()
167209
.name(METRIC_NAME_CACHE_LOAD_DURATION_SECONDS)
@@ -175,6 +217,11 @@ public MetricSnapshots collect() {
175217

176218
try {
177219
cacheEvictionWeight.dataPoint(
220+
CounterSnapshot.CounterDataPointSnapshot.builder()
221+
.labels(labels)
222+
.value(stats.evictionWeight())
223+
.build());
224+
cacheEvictionWeightLegacyGauge.dataPoint(
178225
GaugeSnapshot.GaugeDataPointSnapshot.builder()
179226
.labels(labels)
180227
.value(stats.evictionWeight())
@@ -183,6 +230,17 @@ public MetricSnapshots collect() {
183230
// EvictionWeight metric is unavailable, newer version of Caffeine is needed.
184231
}
185232

233+
if (collectWeightedSize) {
234+
final Optional<? extends Policy.Eviction<?, ?>> eviction = c.getValue().policy().eviction();
235+
if (eviction.isPresent() && eviction.get().weightedSize().isPresent()) {
236+
cacheWeightedSize.dataPoint(
237+
GaugeSnapshot.GaugeDataPointSnapshot.builder()
238+
.labels(labels)
239+
.value(eviction.get().weightedSize().getAsLong())
240+
.build());
241+
}
242+
}
243+
186244
cacheHitTotal.dataPoint(
187245
CounterSnapshot.CounterDataPointSnapshot.builder()
188246
.labels(labels)
@@ -235,12 +293,19 @@ public MetricSnapshots collect() {
235293
}
236294
}
237295

296+
if (collectWeightedSize) {
297+
metricSnapshotsBuilder.metricSnapshot(cacheWeightedSize.build());
298+
}
299+
238300
return metricSnapshotsBuilder
239301
.metricSnapshot(cacheHitTotal.build())
240302
.metricSnapshot(cacheMissTotal.build())
241303
.metricSnapshot(cacheRequestsTotal.build())
242304
.metricSnapshot(cacheEvictionTotal.build())
243-
.metricSnapshot(cacheEvictionWeight.build())
305+
.metricSnapshot(
306+
collectEvictionWeightAsCounter
307+
? cacheEvictionWeight.build()
308+
: cacheEvictionWeightLegacyGauge.build())
244309
.metricSnapshot(cacheLoadFailure.build())
245310
.metricSnapshot(cacheLoadTotal.build())
246311
.metricSnapshot(cacheSize.build())
@@ -250,6 +315,35 @@ public MetricSnapshots collect() {
250315

251316
@Override
252317
public List<String> getPrometheusNames() {
318+
if (!collectWeightedSize) {
319+
return ALL_METRIC_NAMES.stream()
320+
.filter(s -> !METRIC_NAME_CACHE_WEIGHTED_SIZE.equals(s))
321+
.collect(Collectors.toList());
322+
}
253323
return ALL_METRIC_NAMES;
254324
}
325+
326+
public static Builder builder() {
327+
return new Builder();
328+
}
329+
330+
public static class Builder {
331+
332+
private boolean collectEvictionWeightAsCounter = true;
333+
private boolean collectWeightedSize = true;
334+
335+
public Builder collectEvictionWeightAsCounter(boolean collectEvictionWeightAsCounter) {
336+
this.collectEvictionWeightAsCounter = collectEvictionWeightAsCounter;
337+
return this;
338+
}
339+
340+
public Builder collectWeightedSize(boolean collectWeightedSize) {
341+
this.collectWeightedSize = collectWeightedSize;
342+
return this;
343+
}
344+
345+
public CacheMetricsCollector build() {
346+
return new CacheMetricsCollector(collectEvictionWeightAsCounter, collectWeightedSize);
347+
}
348+
}
255349
}

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