Files
postgrest/src/PostgREST/Metrics.hs
T
Michal KleczekandGitHub 77ff11de95 feat: JWT cache implementation based on sieve algorithm (#4084)
Changes:

1. Refactoring and some cleanup of JWT handling code:
* Instead of caching AuthResult cache decoded claims (which signature was verified). Validating claims and determining role is done after cache lookup
* Cleaned up API so that usage of it is simplified: lookupJwtCache cache key >>= parseClaims configJwtAud time
* Handling of JwtCacheState initialization and updates of configuration is encapsulated in Auth.JwtCache module

2. Generic high performance (hopefully) scalable, dynamically resizeable cache implementation based on stm, stm-hamt and sieve algorithm. It also integrates with PostgREST measurements infrastructure providing usage stats (ie. hit ratio, evictions count)
2025-07-29 18:51:41 -05:00

80 lines
3.0 KiB
Haskell

{-# LANGUAGE RecordWildCards #-}
{-|
Module : PostgREST.Logger
Description : Metrics based on the Observation module. See Observation.hs.
-}
module PostgREST.Metrics
( init
, MetricsState (..)
, observationMetrics
, metricsToText
) where
import qualified Data.ByteString.Lazy as LBS
import qualified Hasql.Pool.Observation as SQL
import Prometheus
import PostgREST.Observation
import Protolude
data MetricsState =
MetricsState {
poolTimeouts :: Counter,
poolAvailable :: Gauge,
poolWaiting :: Gauge,
poolMaxSize :: Gauge,
schemaCacheLoads :: Vector Label1 Counter,
schemaCacheQueryTime :: Gauge,
jwtCacheRequests :: Counter,
jwtCacheHits :: Counter,
jwtCacheEvictions :: Counter
}
init :: Int -> IO MetricsState
init configDbPoolSize = do
metricState <- MetricsState <$>
register (counter (Info "pgrst_db_pool_timeouts_total" "The total number of pool connection timeouts")) <*>
register (gauge (Info "pgrst_db_pool_available" "Available connections in the pool")) <*>
register (gauge (Info "pgrst_db_pool_waiting" "Requests waiting to acquire a pool connection")) <*>
register (gauge (Info "pgrst_db_pool_max" "Max pool connections")) <*>
register (vector "status" $ counter (Info "pgrst_schema_cache_loads_total" "The total number of times the schema cache was loaded")) <*>
register (gauge (Info "pgrst_schema_cache_query_time_seconds" "The query time in seconds of the last schema cache load")) <*>
register (counter (Info "pgrst_jwt_cache_requests_total" "The total number of JWT cache lookups")) <*>
register (counter (Info "pgrst_jwt_cache_hits_total" "The total number of JWT cache hits")) <*>
register (counter (Info "pgrst_jwt_cache_evictions_total" "The total number of JWT cache evictions"))
setGauge (poolMaxSize metricState) (fromIntegral configDbPoolSize)
pure metricState
-- Only some observations are used as metrics
observationMetrics :: MetricsState -> ObservationHandler
observationMetrics MetricsState{..} obs = case obs of
(PoolAcqTimeoutObs _) -> do
incCounter poolTimeouts
(HasqlPoolObs (SQL.ConnectionObservation _ status)) -> case status of
SQL.ReadyForUseConnectionStatus -> do
incGauge poolAvailable
SQL.InUseConnectionStatus -> do
decGauge poolAvailable
SQL.TerminatedConnectionStatus _ -> do
decGauge poolAvailable
SQL.ConnectingConnectionStatus -> pure ()
PoolRequest ->
incGauge poolWaiting
PoolRequestFullfilled ->
decGauge poolWaiting
SchemaCacheLoadedObs resTime -> do
withLabel schemaCacheLoads "SUCCESS" incCounter
setGauge schemaCacheQueryTime resTime
SchemaCacheErrorObs{} -> do
withLabel schemaCacheLoads "FAIL" incCounter
JwtCacheLookup True -> incCounter jwtCacheRequests *> incCounter jwtCacheHits
JwtCacheLookup False -> incCounter jwtCacheRequests
JwtCacheEviction -> incCounter jwtCacheEvictions
_ ->
pure ()
metricsToText :: IO LBS.ByteString
metricsToText = exportMetricsAsText