dendrite/internal/caching/immutableinmemorylru.go

96 lines
2.8 KiB
Go

package caching
import (
"fmt"
lru "github.com/hashicorp/golang-lru"
"github.com/matrix-org/gomatrixserverlib"
"github.com/prometheus/client_golang/prometheus"
"github.com/prometheus/client_golang/prometheus/promauto"
)
type ImmutableInMemoryLRUCache struct {
roomVersions *lru.Cache
serverKeys *lru.Cache
}
func NewImmutableInMemoryLRUCache() (*ImmutableInMemoryLRUCache, error) {
roomVersionCache, rvErr := lru.New(RoomVersionMaxCacheEntries)
if rvErr != nil {
return nil, rvErr
}
serverKeysCache, rvErr := lru.New(ServerKeysMaxCacheEntries)
if rvErr != nil {
return nil, rvErr
}
cache := &ImmutableInMemoryLRUCache{
roomVersions: roomVersionCache,
serverKeys: serverKeysCache,
}
cache.configureMetrics()
return cache, nil
}
func (c *ImmutableInMemoryLRUCache) configureMetrics() {
promauto.NewGaugeFunc(prometheus.GaugeOpts{
Namespace: "dendrite",
Subsystem: "caching",
Name: "number_room_version_entries",
Help: "The number of room version entries cached.",
}, func() float64 {
return float64(c.roomVersions.Len())
})
promauto.NewGaugeFunc(prometheus.GaugeOpts{
Namespace: "dendrite",
Subsystem: "caching",
Name: "number_server_key_entries",
Help: "The number of server key entries cached.",
}, func() float64 {
return float64(c.serverKeys.Len())
})
}
func checkForInvalidMutation(cache *lru.Cache, key string, value interface{}) {
if peek, ok := cache.Peek(key); ok && peek != value {
panic(fmt.Sprintf("invalid use of immutable cache tries to mutate existing value of %q", key))
}
}
func (c *ImmutableInMemoryLRUCache) GetRoomVersion(roomID string) (gomatrixserverlib.RoomVersion, bool) {
val, found := c.roomVersions.Get(roomID)
if found && val != nil {
if roomVersion, ok := val.(gomatrixserverlib.RoomVersion); ok {
return roomVersion, true
}
}
return "", false
}
func (c *ImmutableInMemoryLRUCache) StoreRoomVersion(roomID string, roomVersion gomatrixserverlib.RoomVersion) {
checkForInvalidMutation(c.roomVersions, roomID, roomVersion)
c.roomVersions.Add(roomID, roomVersion)
}
func (c *ImmutableInMemoryLRUCache) GetServerKey(
request gomatrixserverlib.PublicKeyLookupRequest,
) (gomatrixserverlib.PublicKeyLookupResult, bool) {
key := fmt.Sprintf("%s/%s", request.ServerName, request.KeyID)
val, found := c.serverKeys.Get(key)
if found && val != nil {
if keyLookupResult, ok := val.(gomatrixserverlib.PublicKeyLookupResult); ok {
return keyLookupResult, true
}
}
return gomatrixserverlib.PublicKeyLookupResult{}, false
}
func (c *ImmutableInMemoryLRUCache) StoreServerKey(
request gomatrixserverlib.PublicKeyLookupRequest,
response gomatrixserverlib.PublicKeyLookupResult,
) {
key := fmt.Sprintf("%s/%s", request.ServerName, request.KeyID)
checkForInvalidMutation(c.roomVersions, key, response)
c.serverKeys.Add(request, response)
}