Package org.mockserver.slo

Class SloSampleStore

java.lang.Object

org.mockserver.slo.SloSampleStore

public class SloSampleStore
extends Object

Process-wide store of recent request samples used to evaluate SloCriteria into an SloVerdict. Mirrors the singleton + reset() pattern of ServiceChaosRegistry / ChaosAutoHaltMonitor.

Each sample is one upstream round-trip (v1 records only Scope.FORWARD traffic): its wall-clock end time, latency, whether it was an error (status null or >= 500), the Scope, and the upstream host. Samples are bounded two ways:

• By count — at most sloWindowMaxSamples (default 50 000); the oldest is evicted when full.
• By age — samples older than sloWindowRetentionMillis (default 600 000 ms) relative to the newest recorded sample are evicted lazily on record and on query.

When sloTrackingEnabled is false (the default), record(long, long, boolean, org.mockserver.slo.Scope, java.lang.String) is a no-op so the forward hot path pays nothing. Queries always work against whatever samples exist.

Latency percentiles use the same algorithm as org.mockserver.mock.drift.PercentileTracker: sort the in-window latencies ascending and take the ceil(p/100 * n) - 1 index (clamped).

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
static final class	SloSampleStore.ErrorCounts	Result of an error-rate query over a window: error and total sample counts.

Constructor Summary

Constructors

Constructor	Description
SloSampleStore()

Method Summary

Modifier and Type	Method	Description
SloSampleStore.ErrorCounts	errorCountsInWindow(long fromEpochMillis, long toEpochMillis, Scope scope, Set<String> hosts)
static SloSampleStore	getInstance()
long[]	latenciesInWindow(long fromEpochMillis, long toEpochMillis, Scope scope, Set<String> hosts)
static Double	percentile(long[] ascendingLatencies, int pct)	The latency percentile (0-100) over the supplied ascending latencies, using the same algorithm as PercentileTracker.percentile.
void	record(long epochMillis, long latencyMillis, boolean isError, Scope scope, String host)	Record one sample.
void	reset()	Clears all samples.
int	size()	The total number of samples currently held (across all scopes/hosts).

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Details

SloSampleStore

public SloSampleStore()

Method Details

getInstance

public static SloSampleStore getInstance()

record

public void record(long epochMillis,
 long latencyMillis,
 boolean isError,
 Scope scope,
 String host)

Record one sample. No-op when sloTrackingEnabled is false so the forward hot path pays nothing when the feature is off.

Parameters:

epochMillis - the sample's wall-clock end time (epoch millis)

latencyMillis - upstream round-trip latency in milliseconds

isError - true when the response was an error (status null or >= 500)

scope - which traffic the sample belongs to (v1 records Scope.FORWARD)

host - the upstream host label, may be null

latenciesInWindow

public long[] latenciesInWindow(long fromEpochMillis,
 long toEpochMillis,
 Scope scope,
 Set<String> hosts)

Returns:

the in-window, in-scope, in-host latencies (ascending order ready for percentile selection), or an empty array when none match.

errorCountsInWindow

public SloSampleStore.ErrorCounts errorCountsInWindow(long fromEpochMillis,
 long toEpochMillis,
 Scope scope,
 Set<String> hosts)

Returns:

error and total sample counts for the in-window, in-scope, in-host samples.

percentile

public static Double percentile(long[] ascendingLatencies,
 int pct)

The latency percentile (0-100) over the supplied ascending latencies, using the same algorithm as PercentileTracker.percentile. Returns null when there are no samples (so the caller can mark the objective INCONCLUSIVE rather than reporting a misleading zero).

size

public int size()

The total number of samples currently held (across all scopes/hosts).

reset

public void reset()

Clears all samples. Called on server reset and for test isolation.