Add is_cache_enabled boolean flag

.env

@@ -89,16 +89,18 @@ METRIC_PARTITIONING_ROUTINE_DELAY_FIRST_RUN_SECONDS=10
 METRIC_PARTITIONINING_PREFILL_PERIOD_DAYS=7
 # Used by `ready` script to ensure metric partitions have been created.
 MINIMUM_REQUIRED_PARTITIONS=30
-# RedisEndpointURL is an url of redis
+# CACHE_ENABLED specifies if cache should be enabled. By default cache is disabled.
+CACHE_ENABLED=true
+# REDIS_ENDPOINT_URL is an url of redis
 REDIS_ENDPOINT_URL=redis:6379
 REDIS_PASSWORD=
-# TTL for cached evm requests
-# TTL should be specified in seconds
+# CACHE_TTL is a TTL for cached evm requests
+# CACHE_TTL should be specified in seconds
 CACHE_TTL=600
-# CachePrefix is used as prefix for any key in the cache, key has such structure:
+# CACHE_PREFIX is used as prefix for any key in the cache, key has such structure:
 # <cache_prefix>:evm-request:<method_name>:sha256:<sha256(body)>
 # Possible values are testnet, mainnet, etc...
-# CachePrefix must not contain colon symbol
+# CACHE_PREFIX must not contain colon symbol
 CACHE_PREFIX=local-chain
 
 ##### Database Config

config/config.go

@@ -37,6 +37,7 @@ type Config struct {
 	MetricPartitioningRoutineInterval      time.Duration
 	MetricPartitioningRoutineDelayFirstRun time.Duration
 	MetricPartitioningPrefillPeriodDays    int
+	CacheEnabled                           bool
 	RedisEndpointURL                       string
 	RedisPassword                          string
 	CacheTTL                               time.Duration
@@ -83,6 +84,7 @@ const (
 	DEFAULT_DATABASE_READ_TIMEOUT_SECONDS                       = 60
 	DATABASE_WRITE_TIMEOUT_SECONDS_ENVIRONMENT_KEY              = "DATABASE_WRITE_TIMEOUT_SECONDS"
 	DEFAULT_DATABASE_WRITE_TIMEOUT_SECONDS                      = 10
+	CACHE_ENABLED_ENVIRONMENT_KEY                               = "CACHE_ENABLED"
 	REDIS_ENDPOINT_URL_ENVIRONMENT_KEY                          = "REDIS_ENDPOINT_URL"
 	REDIS_PASSWORD_ENVIRONMENT_KEY                              = "REDIS_PASSWORD"
 	CACHE_TTL_ENVIRONMENT_KEY                                   = "CACHE_TTL"
@@ -212,6 +214,7 @@ func ReadConfig() Config {
 		MetricPartitioningRoutineInterval:      time.Duration(time.Duration(EnvOrDefaultInt(METRIC_PARTITIONING_ROUTINE_INTERVAL_SECONDS_ENVIRONMENT_KEY, DEFAULT_METRIC_PARTITIONING_ROUTINE_INTERVAL_SECONDS)) * time.Second),
 		MetricPartitioningRoutineDelayFirstRun: time.Duration(time.Duration(EnvOrDefaultInt(METRIC_PARTITIONING_ROUTINE_DELAY_FIRST_RUN_SECONDS_ENVIRONMENT_KEY, DEFAULT_METRIC_PARTITIONING_ROUTINE_DELAY_FIRST_RUN_SECONDS)) * time.Second),
 		MetricPartitioningPrefillPeriodDays:    EnvOrDefaultInt(METRIC_PARTITIONING_PREFILL_PERIOD_DAYS_ENVIRONMENT_KEY, DEFAULT_METRIC_PARTITIONING_PREFILL_PERIOD_DAYS),
+		CacheEnabled:                           EnvOrDefaultBool(CACHE_ENABLED_ENVIRONMENT_KEY, false),
 		RedisEndpointURL:                       os.Getenv(REDIS_ENDPOINT_URL_ENVIRONMENT_KEY),
 		RedisPassword:                          os.Getenv(REDIS_PASSWORD_ENVIRONMENT_KEY),
 		CacheTTL:                               time.Duration(EnvOrDefaultInt(CACHE_TTL_ENVIRONMENT_KEY, 0)) * time.Second,

service/cachemdw/cache.go

@@ -20,7 +20,8 @@ type ServiceCache struct {
 	cacheTTL                 time.Duration
 	decodedRequestContextKey any
 	// cachePrefix is used as prefix for any key in the cache
-	cachePrefix string
+	cachePrefix  string
+	cacheEnabled bool
 
 	*logging.ServiceLogger
 }
@@ -31,6 +32,7 @@ func NewServiceCache(
 	cacheTTL time.Duration,
 	decodedRequestContextKey any,
 	cachePrefix string,
+	cacheEnabled bool,
 	logger *logging.ServiceLogger,
 ) *ServiceCache {
 	return &ServiceCache{
@@ -39,6 +41,7 @@ func NewServiceCache(
 		cacheTTL:                 cacheTTL,
 		decodedRequestContextKey: decodedRequestContextKey,
 		cachePrefix:              cachePrefix,
+		cacheEnabled:             cacheEnabled,
 		ServiceLogger:            logger,
 	}
 }

service/cachemdw/cache_test.go

@@ -78,7 +78,15 @@ func TestUnitTestCacheQueryResponse(t *testing.T) {
 	cacheTTL := time.Hour
 	ctxb := context.Background()
 
-	serviceCache := cachemdw.NewServiceCache(inMemoryCache, blockGetter, cacheTTL, service.DecodedRequestContextKey, defaultCachePrefixString, &logger)
+	serviceCache := cachemdw.NewServiceCache(
+		inMemoryCache,
+		blockGetter,
+		cacheTTL,
+		service.DecodedRequestContextKey,
+		defaultCachePrefixString,
+		true,
+		&logger,
+	)
 
 	req := mkEVMRPCRequestEnvelope(defaultBlockNumber)
 	resp, err := serviceCache.GetCachedQueryResponse(ctxb, req)

service/cachemdw/caching_middleware.go

@@ -19,6 +19,12 @@ func (c *ServiceCache) CachingMiddleware(
 	next http.Handler,
 ) http.HandlerFunc {
 	return func(w http.ResponseWriter, r *http.Request) {
+		// if cache is not enabled - do nothing and forward to next middleware
+		if !c.cacheEnabled {
+			next.ServeHTTP(w, r)
+			return
+		}
+
 		// if we can't get decoded request then forward to next middleware
 		req := r.Context().Value(c.decodedRequestContextKey)
 		decodedReq, ok := (req).(*decode.EVMRPCRequestEnvelope)

service/cachemdw/is_cached_middleware.go

@@ -28,6 +28,12 @@ func (c *ServiceCache) IsCachedMiddleware(
 	next http.Handler,
 ) http.HandlerFunc {
 	return func(w http.ResponseWriter, r *http.Request) {
+		// if cache is not enabled - do nothing and forward to next middleware
+		if !c.cacheEnabled {
+			next.ServeHTTP(w, r)
+			return
+		}
+
 		uncachedContext := context.WithValue(r.Context(), CachedContextKey, false)
 		cachedContext := context.WithValue(r.Context(), CachedContextKey, true)
 

service/cachemdw/middleware_test.go

@@ -24,7 +24,15 @@ func TestE2ETestServiceCacheMiddleware(t *testing.T) {
 	blockGetter := NewMockEVMBlockGetter()
 	cacheTTL := time.Duration(0) // TTL: no expiry
 
-	serviceCache := cachemdw.NewServiceCache(inMemoryCache, blockGetter, cacheTTL, service.DecodedRequestContextKey, defaultCachePrefixString, &logger)
+	serviceCache := cachemdw.NewServiceCache(
+		inMemoryCache,
+		blockGetter,
+		cacheTTL,
+		service.DecodedRequestContextKey,
+		defaultCachePrefixString,
+		true,
+		&logger,
+	)
 
 	emptyHandler := http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {})
 	cachingMdw := serviceCache.CachingMiddleware(emptyHandler)

service/middleware.go

@@ -233,9 +233,9 @@ func createProxyRequestMiddleware(next http.Handler, config config.Config, servi
 			response := r.Context().Value(cachemdw.ResponseContextKey)
 			typedResponse, ok := response.([]byte)
 
-			// if request is cached and response is present in context - serve the request from the cache
+			// if cache is enabled, request is cached and response is present in context - serve the request from the cache
 			// otherwise proxy to the actual backend
-			if isCached && ok {
+			if config.CacheEnabled && isCached && ok {
 				serviceLogger.Logger.Trace().
 					Str("method", r.Method).
 					Str("url", r.URL.String()).
@@ -271,20 +271,23 @@ func createProxyRequestMiddleware(next http.Handler, config config.Config, servi
 			// extract the original hostname the request was sent to
 			requestHostnameContext := context.WithValue(originRoundtripLatencyContext, RequestHostnameContextKey, r.Host)
 
-			var bodyCopy bytes.Buffer
-			tee := io.TeeReader(lrw.body, &bodyCopy)
-			// read all body from reader into bodyBytes, and copy into bodyCopy
-			bodyBytes, err := io.ReadAll(tee)
-			if err != nil {
-				serviceLogger.Error().Err(err).Msg("can't read lrw.body")
-			}
+			enrichedContext := requestHostnameContext
 
-			// replace empty body reader with fresh copy
-			lrw.body = &bodyCopy
-			// set body in context
-			responseContext := context.WithValue(requestHostnameContext, cachemdw.ResponseContextKey, bodyBytes)
+			// if cache is enabled, update enrichedContext with cachemdw.ResponseContextKey -> bodyBytes key-value pair
+			if config.CacheEnabled {
+				var bodyCopy bytes.Buffer
+				tee := io.TeeReader(lrw.body, &bodyCopy)
+				// read all body from reader into bodyBytes, and copy into bodyCopy
+				bodyBytes, err := io.ReadAll(tee)
+				if err != nil {
+					serviceLogger.Error().Err(err).Msg("can't read lrw.body")
+				}
 
-			enrichedContext := responseContext
+				// replace empty body reader with fresh copy
+				lrw.body = &bodyCopy
+				// set body in context
+				enrichedContext = context.WithValue(enrichedContext, cachemdw.ResponseContextKey, bodyBytes)
+			}
 
 			// parse the remote address of the request for use below
 			remoteAddressParts := strings.Split(r.RemoteAddr, ":")

service/service.go

@@ -213,6 +213,7 @@ func createServiceCache(
 		config.CacheTTL,
 		DecodedRequestContextKey,
 		config.CachePrefix,
+		config.CacheEnabled,
 		logger,
 	)