Add configurable memory limits and LRU eviction for runtime cache

2026-10-01 03:56:38 +08:00 · 2026-09-13 00:41:04 +08:00
parent 2989649445
commit 386fc358d1
13 changed files with 634 additions and 93 deletions
@@ -0,0 +1,118 @@
+package service
+
+import (
+	"context"
+	"fmt"
+	"strings"
+	"testing"
+	"time"
+
+	"go.uber.org/zap"
+
+	"github.com/truewhile/MeBox/internal/config"
+	"github.com/truewhile/MeBox/internal/model"
+)
+
+func newRuntimeCacheForTest(t *testing.T, maxMB int) *RuntimeCacheService {
+	t.Helper()
+	cfg := &config.Config{}
+	cfg.Cache.MemoryMaxSizeMB = maxMB
+	return NewRuntimeCacheService(cfg, zap.NewNop())
+}
+
+func TestRuntimeCacheEvictsByByteBudget(t *testing.T) {
+	cache := newRuntimeCacheForTest(t, 1)
+	cache.SetObject("large", strings.Repeat("a", 800<<10), time.Minute)
+	cache.SetObject("small", strings.Repeat("b", 300<<10), time.Minute)
+
+	if cache.bytesUsed > cache.maxBytes {
+		t.Fatalf("cache bytes=%d exceeds max=%d", cache.bytesUsed, cache.maxBytes)
+	}
+	if _, ok := cache.GetObject("large"); ok {
+		t.Fatal("expected oldest large entry to be evicted")
+	}
+	if _, ok := cache.GetObject("small"); !ok {
+		t.Fatal("expected newest small entry to remain cached")
+	}
+}
+
+func TestRuntimeCacheSkipsOversizedObject(t *testing.T) {
+	cache := newRuntimeCacheForTest(t, 1)
+	cache.SetObject("huge", strings.Repeat("x", 2<<20), time.Minute)
+
+	if _, ok := cache.GetObject("huge"); ok {
+		t.Fatal("oversized object must not be cached")
+	}
+	if cache.bytesUsed != 0 {
+		t.Fatalf("bytesUsed=%d, want 0", cache.bytesUsed)
+	}
+}
+
+func TestRuntimeCachePrefixDeleteReleasesByteBudget(t *testing.T) {
+	cache := newRuntimeCacheForTest(t, 2)
+	for i := 0; i < 4; i++ {
+		cache.SetJSON(context.Background(), fmt.Sprintf("media:%d", i), strings.Repeat("x", 64<<10), time.Minute)
+	}
+	if cache.bytesUsed == 0 {
+		t.Fatal("expected cached bytes")
+	}
+	cache.DeletePrefix(context.Background(), "media:")
+	if cache.bytesUsed != 0 {
+		t.Fatalf("bytesUsed=%d after prefix delete, want 0", cache.bytesUsed)
+	}
+	for i := 0; i < 4; i++ {
+		var out string
+		if cache.GetJSON(context.Background(), fmt.Sprintf("media:%d", i), &out) {
+			t.Fatalf("entry media:%d should have been deleted", i)
+		}
+	}
+}
+
+func TestRuntimeCacheStillEnforcesEntryLimit(t *testing.T) {
+	cache := newRuntimeCacheForTest(t, 1)
+	cache.limit = 3
+	for i := 0; i < 5; i++ {
+		cache.SetObject(fmt.Sprintf("item-%d", i), i, time.Minute)
+	}
+	if got := cache.entryCountLocked(); got != 3 {
+		t.Fatalf("entry count=%d, want 3", got)
+	}
+}
+
+func TestRuntimeCacheEstimatesMediaRows(t *testing.T) {
+	rows := []model.Media{{
+		Title:       strings.Repeat("t", 1024),
+		Path:        "/media/movies/example.mkv",
+		PosterURL:   "https://image.example/poster.jpg",
+		BackdropURL: "https://image.example/backdrop.jpg",
+		Overview:    strings.Repeat("o", 2048),
+		Genres:      "Action,Adventure",
+	}}
+	size := estimateRuntimeCacheObjectSize("media:test", rows)
+	if size < int64(len(rows[0].Title)+len(rows[0].Overview)) {
+		t.Fatalf("estimated size %d is smaller than payload", size)
+	}
+}
+
+func TestRuntimeCacheSetMaxSizeEvictsImmediately(t *testing.T) {
+	cache := newRuntimeCacheForTest(t, 2)
+	cache.SetObject("old", strings.Repeat("a", 700<<10), time.Minute)
+	cache.SetObject("new", strings.Repeat("b", 700<<10), time.Minute)
+	if cache.bytesUsed <= 1<<20 {
+		t.Fatalf("test setup bytesUsed=%d, want >1MiB", cache.bytesUsed)
+	}
+
+	cache.SetMaxSizeMB(1)
+	if cache.maxBytes != 1<<20 {
+		t.Fatalf("maxBytes=%d, want 1MiB", cache.maxBytes)
+	}
+	if cache.bytesUsed > cache.maxBytes {
+		t.Fatalf("bytesUsed=%d exceeds maxBytes=%d", cache.bytesUsed, cache.maxBytes)
+	}
+	if _, ok := cache.GetObject("old"); ok {
+		t.Fatal("oldest entry should be evicted after lowering cache limit")
+	}
+	if _, ok := cache.GetObject("new"); !ok {
+		t.Fatal("newest entry should remain after lowering cache limit")
+	}
+}