Prometheus Proxy/io.prometheus.agent/HttpClientCache

HttpClientCache

internal class HttpClientCache(maxCacheSize: Int = 100, maxAge: Duration = 30.minutes, maxIdleTime: Duration = 10.minutes, cleanupInterval: Duration = 5.minutes)(source)

LRU cache for Ktor HttpClient instances keyed by authentication credentials.

Caches HTTP clients to avoid creating a new client per scrape request. Entries are evicted when they exceed maxAge, sit idle longer than maxIdleTime, or when the cache exceeds maxCacheSize (least-recently-used eviction). A background coroutine periodically cleans up expired entries. Credential-based keys are masked in logs to prevent leaking secrets.

Parameters

maxCacheSize

maximum number of cached clients

maxAge

maximum lifetime of a cache entry

maxIdleTime

maximum idle time before an entry is considered expired

cleanupInterval

interval between background cleanup sweeps

See also

AgentHttpService

Constructors

HttpClientCache

constructor(maxCacheSize: Int = 100, maxAge: Duration = 30.minutes, maxIdleTime: Duration = 10.minutes, cleanupInterval: Duration = 5.minutes)

Types

class CacheEntry(val client: HttpClient, val createdAt: Long = System.currentTimeMillis(), var lastAccessedAt: Long = System.currentTimeMillis())

data class CacheStats(val totalEntries: Int, val validEntries: Int, val expiredEntries: Int)

data class ClientKey(val username: String?, val password: String?)

object Companion

Functions

suspend fun close()

currentCacheSize

fun currentCacheSize(): Int

suspend fun getCacheStats(): HttpClientCache.CacheStats

getOrCreateClient

suspend fun getOrCreateClient(key: HttpClientCache.ClientKey, clientFactory: () -> HttpClient): HttpClientCache.CacheEntry

onFinishedWithClient

suspend fun onFinishedWithClient(entry: HttpClientCache.CacheEntry)