Gek/cache bot search page (#3530)

* feat: add general purpose key/val caching layer

* feat: cache bot/metadata response page for 10 seconds

core/cache/cache.go

@@ -0,0 +1,82 @@
+package cache
+
+import (
+	"time"
+
+	"github.com/jellydator/ttlcache/v3"
+)
+
+// CacheContainer is a container for all caches.
+type CacheContainer struct {
+	caches map[string]*CacheInstance
+}
+
+// CacheInstance is a single cache instance.
+type CacheInstance struct {
+	cache *ttlcache.Cache[string, []byte]
+}
+
+// This is the global singleton instance. (To be removed after refactor).
+var _instance *CacheContainer
+
+// NewCache creates a new cache instance.
+func NewGlobalCache() *CacheContainer {
+	_instance = &CacheContainer{
+		caches: make(map[string]*CacheInstance),
+	}
+
+	return _instance
+}
+
+// GetCache returns the cache instance.
+func GetGlobalCache() *CacheContainer {
+	if _instance != nil {
+		return _instance
+	}
+	return NewGlobalCache()
+}
+
+// GetOrCreateCache returns the cache instance or creates a new one.
+func (c *CacheContainer) GetOrCreateCache(name string, expiration time.Duration) *CacheInstance {
+	if _, ok := c.caches[name]; !ok {
+		c.CreateCache(name, expiration)
+	}
+	return c.caches[name]
+}
+
+// CreateCache creates a new cache instance.
+func (c *CacheContainer) CreateCache(name string, expiration time.Duration) *CacheInstance {
+	cache := ttlcache.New[string, []byte](
+		ttlcache.WithTTL[string, []byte](expiration),
+		ttlcache.WithDisableTouchOnHit[string, []byte](),
+	)
+	ci := &CacheInstance{cache: cache}
+	c.caches[name] = ci
+	go cache.Start()
+	return ci
+}
+
+// GetCache returns the cache instance.
+func (c *CacheContainer) GetCache(name string) *CacheInstance {
+	return c.caches[name]
+}
+
+// GetValueForKey returns the value for the given key.
+func (ci *CacheInstance) GetValueForKey(key string) []byte {
+	value := ci.cache.Get(key, ttlcache.WithDisableTouchOnHit[string, []byte]())
+	if value == nil {
+		return nil
+	}
+
+	if value.IsExpired() {
+		return nil
+	}
+
+	val := value.Value()
+	return val
+}
+
+// Set sets the value for the given key..
+func (ci *CacheInstance) Set(key string, value []byte) {
+	ci.cache.Set(key, value, 0)
+}

core/cache/cache_test.go

@@ -0,0 +1,72 @@
+package cache
+
+import (
+	"strconv"
+	"testing"
+	"time"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestCache(t *testing.T) {
+	expiration := 5 * time.Second
+	globalCache := GetGlobalCache()
+	assert.NotNil(t, globalCache, "NewGlobalCache should return a non-nil instance")
+	assert.Equal(t, globalCache, GetGlobalCache(), "GetGlobalCache should return the created instance")
+
+	cacheName := "testCache"
+	globalCache.CreateCache(cacheName, expiration)
+
+	createdCache := globalCache.GetCache(cacheName)
+	assert.NotNil(t, createdCache, "GetCache should return a non-nil cache")
+
+	key := "testKey"
+	value := []byte("testValue")
+	createdCache.Set(key, value)
+
+	// Wait for cache to expire
+	time.Sleep(expiration + 1*time.Second)
+
+	// Verify that the cache has expired
+	ci := globalCache.GetCache(cacheName)
+	cachedValue := ci.GetValueForKey(key)
+	assert.Nil(t, cachedValue, "Cache should not contain the value after expiration")
+}
+
+func TestConcurrentAccess(t *testing.T) {
+	// Test concurrent access to the cache
+	globalCache := NewGlobalCache()
+	cacheName := "concurrentCache"
+	expiration := 5 * time.Second
+	globalCache.CreateCache(cacheName, expiration)
+
+	// Start multiple goroutines to access the cache concurrently
+	numGoroutines := 10
+	keyPrefix := "key"
+	valuePrefix := "value"
+
+	done := make(chan struct{})
+	for i := 0; i < numGoroutines; i++ {
+		go func(index int) {
+			defer func() { done <- struct{}{} }()
+
+			cache := globalCache.GetCache(cacheName)
+			key := keyPrefix + strconv.Itoa(index)
+			value := valuePrefix + strconv.Itoa(index)
+
+			cache.Set(key, []byte(value))
+
+			// Simulate some work
+			time.Sleep(100 * time.Millisecond)
+
+			ci := globalCache.GetCache(cacheName)
+			cachedValue := string(ci.GetValueForKey(key))
+			assert.Equal(t, value, cachedValue, "Cached value should match the set value")
+		}(i)
+	}
+
+	// Wait for all goroutines to finish
+	for i := 0; i < numGoroutines; i++ {
+		<-done
+	}
+}