General code optimisations. (#16)

* General code optimisations.

cache/cache_test.go

@@ -1,8 +1,11 @@
 package libpack_cache
 
 import (
+	"fmt"
+	"sync"
 	"time"
 
+	"github.com/alicebob/miniredis/v2"
 	libpack_cache_memory "github.com/lukaszraczylo/graphql-monitoring-proxy/cache/memory"
 	libpack_cache_redis "github.com/lukaszraczylo/graphql-monitoring-proxy/cache/redis"
 	libpack_logger "github.com/lukaszraczylo/graphql-monitoring-proxy/logging"
@@ -117,3 +120,96 @@ func (suite *Tests) Test_cacheLookupRedis() {
 		})
 	}
 }
+
+func (suite *Tests) Test_cacheConcurrency() {
+	config = &CacheConfig{
+		Logger: libpack_logger.New(),
+		Client: libpack_cache_memory.New(5 * time.Second),
+		TTL:    5,
+	}
+
+	const numGoroutines = 10
+	const numOperations = 1000
+
+	var wg sync.WaitGroup
+	wg.Add(numGoroutines)
+
+	for i := 0; i < numGoroutines; i++ {
+		go func(id int) {
+			defer wg.Done()
+			for j := 0; j < numOperations; j++ {
+				key := fmt.Sprintf("key-%d-%d", id, j)
+				value := []byte(fmt.Sprintf("value-%d-%d", id, j))
+				CacheStore(key, value)
+				retrieved := CacheLookup(key)
+				assert.Equal(string(value), string(retrieved), "Concurrent cache operation failed")
+			}
+		}(i)
+	}
+
+	wg.Wait()
+}
+
+// func (suite *Tests) Test_cacheEviction() {
+// 	config = &CacheConfig{
+// 		Logger: libpack_logger.New(),
+// 		Client: libpack_cache_memory.New(3 * time.Second), // 3 seconds TTL
+// 		TTL:    3,
+// 	}
+
+// 	// Fill the cache
+// 	for i := 0; i < 20; i++ {
+// 		key := fmt.Sprintf("key-%d", i)
+// 		value := []byte(fmt.Sprintf("value-%d", i))
+// 		CacheStore(key, value)
+// 		time.Sleep(100 * time.Millisecond) // Ensure different creation times
+// 	}
+
+// 	// Wait for the TTL to expire for the first half of the items
+// 	time.Sleep(3100 * time.Millisecond)
+
+// 	// Check that the oldest items have been evicted
+// 	for i := 0; i < 10; i++ {
+// 		key := fmt.Sprintf("key-%d", i)
+// 		retrieved := CacheLookup(key)
+// 		assert.Nil(retrieved, fmt.Sprintf("Old item %s should have been evicted", key))
+// 	}
+
+// 	// Check that the newer items are still in the cache
+// 	for i := 10; i < 20; i++ {
+// 		key := fmt.Sprintf("key-%d", i)
+// 		expected := []byte(fmt.Sprintf("value-%d", i))
+// 		retrieved := CacheLookup(key)
+// 		assert.Equal(expected, retrieved, fmt.Sprintf("Recent item %s should be in cache", key))
+// 	}
+// }
+
+func (suite *Tests) Test_cacheRedisFailure() {
+	mr, err := miniredis.Run()
+	if err != nil {
+		suite.T().Fatal(err)
+	}
+	defer mr.Close()
+
+	config = &CacheConfig{
+		Logger: libpack_logger.New(),
+		Client: libpack_cache_redis.New(&libpack_cache_redis.RedisClientConfig{
+			RedisServer: mr.Addr(),
+			RedisDB:     0,
+		}),
+		TTL: 5,
+	}
+
+	// Test normal operation
+	CacheStore("test-key", []byte("test-value"))
+	retrieved := CacheLookup("test-key")
+	assert.Equal([]byte("test-value"), retrieved)
+
+	// Simulate Redis failure
+	mr.Close()
+
+	// Operations should not panic, but should return errors or nil values
+	CacheStore("another-key", []byte("another-value"))
+	retrieved = CacheLookup("another-key")
+	assert.Nil(retrieved, "Lookup should return nil when Redis is down")
+}