snapshot of https://github.com/centrifugal/centrifugo.git (master, 2026-09-16; blobs > 131072B omitted)

internal/config/cache_test.go

@@ -0,0 +1,80 @@
+package config
+
+import (
+	"math"
+	"strconv"
+	"testing"
+	"time"
+
+	"github.com/stretchr/testify/require"
+)
+
+func TestRollingCache(t *testing.T) {
+	size := 30
+	shardCount := 1
+	cache := newRollingCache(size, shardCount)
+
+	// Testing Set.
+	channel := "channel1"
+	value := channelOptionsResult{nsName: "value1"}
+	ttl := 200 * time.Millisecond
+	cache.Set(channel, value, ttl)
+
+	// Testing Get after Set.
+	gotValue, ok := cache.Get(channel)
+	require.True(t, ok)
+	require.Equal(t, value, gotValue)
+
+	// Testing Get after expiry.
+	time.Sleep(400 * time.Millisecond)
+	_, ok = cache.Get(channel)
+	require.False(t, ok)
+
+	// Testing if data rolls over.
+	// Setting more data than cache size, to see if rolling over works without errors.
+	for i := 0; i < size+10; i++ {
+		channel := "channel" + strconv.Itoa(i)
+		value := channelOptionsResult{nsName: "value" + strconv.Itoa(i)}
+		cache.Set(channel, value, ttl)
+	}
+
+	// The first 10 items should have been rolled over and replaced.
+	// So, channel0, channel1, ... channel9 should no longer be in the cache.
+	for i := 0; i < 10; i++ {
+		channel := "channel" + strconv.Itoa(i)
+		_, ok = cache.Get(channel)
+		require.False(t, ok, channel)
+	}
+
+	// Whereas, the items from channel10 onwards should still be there.
+	for i := 10; i < size+10; i++ {
+		channel := "channel" + strconv.Itoa(i)
+		gotValue, ok := cache.Get(channel)
+		require.True(t, ok)
+		require.Equal(t, channelOptionsResult{nsName: "value" + strconv.Itoa(i)}, gotValue)
+	}
+}
+
+// TestRollingCacheIndexOverflow guards against the rolling index wrapping into
+// negative values. The index is bumped on every Set, so on a long-running node
+// it eventually overflows; with a signed counter the wrap made the modulo
+// negative and Set panicked with "index out of range".
+func TestRollingCacheIndexOverflow(t *testing.T) {
+	cache := newRollingCache(channelOptionsCacheSize, 1)
+	shard := cache.shardForKey("channel")
+	shard.index.Store(math.MaxUint32) // Next Set wraps the index.
+
+	ttl := time.Minute
+	for i := 0; i < 2*channelOptionsCacheSize; i++ {
+		channel := "channel" + strconv.Itoa(i)
+		cache.Set(channel, channelOptionsResult{nsName: "value" + strconv.Itoa(i)}, ttl)
+	}
+
+	// The most recent shardSize items must still be readable after the wrap.
+	for i := channelOptionsCacheSize; i < 2*channelOptionsCacheSize; i++ {
+		channel := "channel" + strconv.Itoa(i)
+		gotValue, ok := cache.Get(channel)
+		require.True(t, ok, channel)
+		require.Equal(t, channelOptionsResult{nsName: "value" + strconv.Itoa(i)}, gotValue)
+	}
+}