Add more robust cache invalidation to CachingBucket

This change makes use of `add` operations for special "lock" cache
entries to ensure that when items in object storage are mutated, stale
results are not immediately stored to cache again.

It does this by `set`ing "lock" cache entries with a short TTL when an
item in object storage is about to be mutated. This prevents reads of
the item from caching the results afterwards. After the item is mutated
in object storage, its cache entries (excluding the lock entries) are
deleted. After the lock entries expire, reads of the item are allowed
to store results in the cache again.

Part of #9386

go.mod

@@ -22,7 +22,7 @@ require (
 	github.com/golang/snappy v0.0.4
 	github.com/google/gopacket v1.1.19
 	github.com/gorilla/mux v1.8.1
-	github.com/grafana/dskit v0.0.0-20241007163720-de20fd2fe818
+	github.com/grafana/dskit v0.0.0-20241009141103-2e104a8053fa
 	github.com/grafana/e2e v0.1.2-0.20240118170847-db90b84177fc
 	github.com/hashicorp/golang-lru v1.0.2 // indirect
 	github.com/json-iterator/go v1.1.12
@@ -205,7 +205,7 @@ require (
 	github.com/googleapis/enterprise-certificate-proxy v0.3.4 // indirect
 	github.com/googleapis/gax-go/v2 v2.13.0 // indirect
 	github.com/gosimple/slug v1.1.1 // indirect
-	github.com/grafana/gomemcache v0.0.0-20240229205252-cd6a66d6fb56 // indirect
+	github.com/grafana/gomemcache v0.0.0-20240229205252-cd6a66d6fb56
 	github.com/hashicorp/consul/api v1.29.4 // indirect
 	github.com/hashicorp/errwrap v1.1.0 // indirect
 	github.com/hashicorp/go-cleanhttp v0.5.2 // indirect

go.sum

@@ -1256,8 +1256,8 @@ github.com/grafana-tools/sdk v0.0.0-20220919052116-6562121319fc h1:PXZQA2WCxe85T
 github.com/grafana-tools/sdk v0.0.0-20220919052116-6562121319fc/go.mod h1:AHHlOEv1+GGQ3ktHMlhuTUwo3zljV3QJbC0+8o2kn+4=
 github.com/grafana/alerting v0.0.0-20240926144415-27f4e81b4b6b h1:UO4mv94pG1kzKCgBKh20TXdACBCAK2vYjV3Q2MlcpEQ=
 github.com/grafana/alerting v0.0.0-20240926144415-27f4e81b4b6b/go.mod h1:GMLi6d09Xqo96fCVUjNk//rcjP5NKEdjOzfWIffD5r4=
-github.com/grafana/dskit v0.0.0-20241007163720-de20fd2fe818 h1:VPMurXtl+ONN13d9ge1TGTJDBsJNr9Vb1pNQHpQ/aro=
-github.com/grafana/dskit v0.0.0-20241007163720-de20fd2fe818/go.mod h1:SPLNCARd4xdjCkue0O6hvuoveuS1dGJjDnfxYe405YQ=
+github.com/grafana/dskit v0.0.0-20241009141103-2e104a8053fa h1:jfSQq+jfs1q0cZr9n4u9g6Wz3423VJVE9grnLpx+eS4=
+github.com/grafana/dskit v0.0.0-20241009141103-2e104a8053fa/go.mod h1:SPLNCARd4xdjCkue0O6hvuoveuS1dGJjDnfxYe405YQ=
 github.com/grafana/e2e v0.1.2-0.20240118170847-db90b84177fc h1:BW+LjKJDz0So5LI8UZfW5neWeKpSkWqhmGjQFzcFfLM=
 github.com/grafana/e2e v0.1.2-0.20240118170847-db90b84177fc/go.mod h1:JVmqPBe8A/pZWwRoJW5ZjyALeY5OXMzPl7LrVXOdZAI=
 github.com/grafana/franz-go v0.0.0-20241009101240-fa97d35e871f h1:nsrRsQHfpqs6dWxErIOS3gD6R20H/9XM0ItykNtBFW8=

pkg/ruler/rulestore/bucketclient/bucket_client_test.go

@@ -462,7 +462,7 @@ func TestCachingAndInvalidation(t *testing.T) {
 
 		cacheCfg := bucketcache.NewCachingBucketConfig()
 		cacheCfg.CacheIter("rule-iter", mockCache, matchAll, time.Minute, iterCodec)
-		cacheCfg.CacheGet("rule-groups", mockCache, matchAll, 1024^2, time.Minute, time.Minute, time.Minute, true)
+		cacheCfg.CacheGet("rule-groups", mockCache, matchAll, 1024^2, time.Minute, time.Minute, time.Minute)
 		cacheClient, err := bucketcache.NewCachingBucket("rule-store", baseClient, cacheCfg, log.NewNopLogger(), prometheus.NewPedanticRegistry())
 		require.NoError(t, err)
 
@@ -478,28 +478,37 @@ func TestCachingAndInvalidation(t *testing.T) {
 
 	t.Run("list users with cache", func(t *testing.T) {
 		mockCache, ruleStore := setup(t)
+		startStores := mockCache.CountStoreCalls()
+		startFetches := mockCache.CountFetchCalls()
+
 		users, err := ruleStore.ListAllUsers(context.Background())
 
 		require.NoError(t, err)
 		require.Equal(t, []string{"user1", "user2"}, users)
 
-		require.Equal(t, 1, mockCache.CountStoreCalls())
-		require.Equal(t, 1, mockCache.CountFetchCalls())
+		require.Equal(t, 1, mockCache.CountStoreCalls()-startStores)
+		require.Equal(t, 1, mockCache.CountFetchCalls()-startFetches)
 	})
 
 	t.Run("list users no cache", func(t *testing.T) {
 		mockCache, rs := setup(t)
+		startStores := mockCache.CountStoreCalls()
+		startFetches := mockCache.CountFetchCalls()
+
 		users, err := rs.ListAllUsers(context.Background(), rulestore.WithCacheDisabled())
 
 		require.NoError(t, err)
 		require.Equal(t, []string{"user1", "user2"}, users)
 
-		require.Equal(t, 1, mockCache.CountStoreCalls())
-		require.Equal(t, 0, mockCache.CountFetchCalls())
+		require.Equal(t, 1, mockCache.CountStoreCalls()-startStores)
+		require.Equal(t, 0, mockCache.CountFetchCalls()-startFetches)
 	})
 
 	t.Run("list rule groups with cache", func(t *testing.T) {
 		mockCache, ruleStore := setup(t)
+		startStores := mockCache.CountStoreCalls()
+		startFetches := mockCache.CountFetchCalls()
+
 		groups, err := ruleStore.ListRuleGroupsForUserAndNamespace(context.Background(), "user1", "")
 
 		require.NoError(t, err)
@@ -521,12 +530,15 @@ func TestCachingAndInvalidation(t *testing.T) {
 			},
 		}, groups)
 
-		require.Equal(t, 1, mockCache.CountStoreCalls())
-		require.Equal(t, 1, mockCache.CountFetchCalls())
+		require.Equal(t, 1, mockCache.CountStoreCalls()-startStores)
+		require.Equal(t, 1, mockCache.CountFetchCalls()-startFetches)
 	})
 
 	t.Run("list rule groups no cache", func(t *testing.T) {
 		mockCache, ruleStore := setup(t)
+		startStores := mockCache.CountStoreCalls()
+		startFetches := mockCache.CountFetchCalls()
+
 		groups, err := ruleStore.ListRuleGroupsForUserAndNamespace(context.Background(), "user1", "", rulestore.WithCacheDisabled())
 
 		require.NoError(t, err)
@@ -548,48 +560,54 @@ func TestCachingAndInvalidation(t *testing.T) {
 			},
 		}, groups)
 
-		require.Equal(t, 1, mockCache.CountStoreCalls())
-		require.Equal(t, 0, mockCache.CountFetchCalls())
+		require.Equal(t, 1, mockCache.CountStoreCalls()-startStores)
+		require.Equal(t, 0, mockCache.CountFetchCalls()-startFetches)
 	})
 
 	t.Run("get rule group from cache", func(t *testing.T) {
 		mockCache, ruleStore := setup(t)
+		startStores := mockCache.CountStoreCalls()
+		startFetches := mockCache.CountFetchCalls()
+
 		group, err := ruleStore.GetRuleGroup(context.Background(), "user1", "world", "another namespace testGroup")
 
 		require.NoError(t, err)
 		require.NotNil(t, group)
 
-		require.Equal(t, 2, mockCache.CountStoreCalls())
-		require.Equal(t, 1, mockCache.CountFetchCalls())
+		require.Equal(t, 2, mockCache.CountStoreCalls()-startStores) // content set + exists set
+		require.Equal(t, 1, mockCache.CountFetchCalls()-startFetches)
 	})
 
 	t.Run("get rule groups after invalidation", func(t *testing.T) {
 		mockCache, ruleStore := setup(t)
+		startStores := mockCache.CountStoreCalls()
+		startFetches := mockCache.CountFetchCalls()
+		startDeletes := mockCache.CountDeleteCalls()
+
 		group, err := ruleStore.GetRuleGroup(context.Background(), "user1", "world", "another namespace testGroup")
 
 		require.NoError(t, err)
 		require.NotNil(t, group)
 		require.Zero(t, group.QueryOffset)
 
-		require.Equal(t, 2, mockCache.CountStoreCalls())
-		require.Equal(t, 1, mockCache.CountFetchCalls())
+		require.Equal(t, 2, mockCache.CountStoreCalls()-startStores) // content set + exists set
+		require.Equal(t, 1, mockCache.CountFetchCalls()-startFetches)
 
-		origDeletes := mockCache.CountDeleteCalls()
 		group.QueryOffset = 42 * time.Second
 		require.NoError(t, ruleStore.SetRuleGroup(context.Background(), group.User, group.Namespace, group))
 
-		require.Equal(t, 2, mockCache.CountStoreCalls())
-		require.Equal(t, 1, mockCache.CountFetchCalls())
-		require.Equal(t, 2, mockCache.CountDeleteCalls()-origDeletes)
+		require.Equal(t, 4, mockCache.CountStoreCalls()-startStores) // += content lock + exists lock
+		require.Equal(t, 1, mockCache.CountFetchCalls()-startFetches)
+		require.Equal(t, 2, mockCache.CountDeleteCalls()-startDeletes)
 
 		modifiedGroup, err := ruleStore.GetRuleGroup(context.Background(), "user1", "world", "another namespace testGroup")
 		require.NoError(t, err)
 		require.NotNil(t, modifiedGroup)
 		require.Equal(t, 42*time.Second, modifiedGroup.QueryOffset)
 
-		require.Equal(t, 4, mockCache.CountStoreCalls())
-		require.Equal(t, 2, mockCache.CountFetchCalls())
-		require.Equal(t, 2, mockCache.CountDeleteCalls()-origDeletes)
+		require.Equal(t, 6, mockCache.CountStoreCalls()-startStores) // += content set + exists set
+		require.Equal(t, 2, mockCache.CountFetchCalls()-startFetches)
+		require.Equal(t, 2, mockCache.CountDeleteCalls()-startDeletes)
 	})
 }
 

pkg/ruler/store_mock_test.go

@@ -55,7 +55,7 @@ func newInMemoryRuleStore(t *testing.T) (*cache.InstrumentedMockCache, *bucketcl
 	mockCache := cache.NewInstrumentedMockCache()
 	cfg := bucketcache.NewCachingBucketConfig()
 	cfg.CacheIter("iter", mockCache, isNotTenantsDir, time.Minute, &bucketcache.JSONIterCodec{})
-	cfg.CacheGet("rules", mockCache, isRuleGroup, 1024^2, time.Minute, time.Minute, time.Minute, true)
+	cfg.CacheGet("rules", mockCache, isRuleGroup, 1024^2, time.Minute, time.Minute, time.Minute)
 
 	cachingBkt, err := bucketcache.NewCachingBucket("rules", bkt, cfg, log.NewNopLogger(), prometheus.NewPedanticRegistry())
 	require.NoError(t, err)