feat(gateway): make request body size configurable via env

.env.example

@@ -75,6 +75,10 @@ RATE_LIMIT_VERIFIED_RPM=120
 # Cleanup interval for stale buckets (seconds)
 RATE_LIMIT_CLEANUP_INTERVAL=300
 
+# Request Body Size Configuration
+# Maximum request body size in MB (default: 10)
+MAX_REQUEST_BODY_MB=10
+
 # Request Timeout Configuration
 # Global request timeout (seconds)
 REQUEST_TIMEOUT_SECONDS=60

gateway/cache.go

@@ -46,26 +46,26 @@ func CacheMiddleware() gin.HandlerFunc {
 
 		// Read request body to generate cache key
 		// Check Content-Length first to reject oversized requests immediately
-		const maxBodySize = 10 * 1024 * 1024
+		maxSize := getMaxBodySize()
 		// ContentLength == -1 means unknown (chunked encoding or no header), proceed to MaxBytesReader
-		if c.Request.ContentLength > maxBodySize {
+		if c.Request.ContentLength > maxSize {
 			c.Header("Connection", "close")
-			c.JSON(413, gin.H{"error": "Payload too large", "max_size": "10MB"})
+			c.JSON(413, gin.H{"error": "Payload too large", "max_size": fmt.Sprintf("%dMB", maxSize/1024/1024)})
 			c.Abort()
 			return
 		}
 
 		var requestBody []byte
 		var err error
 		if c.Request.Body != nil {
-			c.Request.Body = http.MaxBytesReader(c.Writer, c.Request.Body, int64(maxBodySize))
+			c.Request.Body = http.MaxBytesReader(c.Writer, c.Request.Body, maxSize)
 			requestBody, err = io.ReadAll(c.Request.Body)
 			if err != nil {
 				// If body too large, MaxBytesReader returns error
 				var maxBytesErr *http.MaxBytesError
 				if errors.As(err, &maxBytesErr) {
 					c.Header("Connection", "close")
-					c.JSON(413, gin.H{"error": "Payload too large", "max_size": "10MB"})
+					c.JSON(413, gin.H{"error": "Payload too large", "max_size": fmt.Sprintf("%dMB", maxSize/1024/1024)})
 					c.Abort()
 					return
 				}

gateway/config.go

@@ -93,3 +93,14 @@ func getVerifierTimeout() time.Duration { return getPositiveTimeout("VERIFIER_TI
 func getHealthCheckTimeout() time.Duration {
 	return getPositiveTimeout("HEALTH_CHECK_TIMEOUT_SECONDS", 2)
 }
+
+// getMaxBodySize returns the maximum request body size in bytes, configured via
+// the MAX_REQUEST_BODY_MB environment variable. Defaults to 10MB.
+func getMaxBodySize() int64 {
+	mb := getEnvAsInt("MAX_REQUEST_BODY_MB", 10)
+	if mb <= 0 {
+		log.Printf("Warning: MAX_REQUEST_BODY_MB must be positive, using default 10")
+		mb = 10
+	}
+	return int64(mb) * 1024 * 1024
+}

gateway/main.go

@@ -463,13 +463,13 @@ func handleSummarize(c *gin.Context) {
 	// Read body if not already available
 	if requestBody == nil {
 		// Read body with limit (only if middleware didn't process it)
-		const maxBodySize = 10 * 1024 * 1024
-		c.Request.Body = http.MaxBytesReader(c.Writer, c.Request.Body, int64(maxBodySize))
+		maxSize := getMaxBodySize()
+		c.Request.Body = http.MaxBytesReader(c.Writer, c.Request.Body, maxSize)
 		requestBody, err = io.ReadAll(c.Request.Body)
 		if err != nil {
 			var maxBytesErr *http.MaxBytesError
 			if errors.As(err, &maxBytesErr) {
-				c.JSON(413, gin.H{"error": "Payload too large", "max_size": "10MB"})
+				c.JSON(413, gin.H{"error": "Payload too large", "max_size": fmt.Sprintf("%dMB", maxSize/1024/1024)})
 			} else {
 				respondError(c, 500, "request_body_read_failed", err)
 			}