[client] Increase mgmt grpc buff size to 16MB (#6641)

shared/management/client/grpc.go

@@ -33,10 +33,15 @@ const ConnectTimeout = 10 * time.Second
 const healthCheckTimeout = 5 * time.Second
 
 const (
-	// EnvMaxRecvMsgSize overrides the default gRPC max receive message size (4 MB)
+	// EnvMaxRecvMsgSize overrides the default gRPC max receive message size
 	// for the management client connection. Value is in bytes.
 	EnvMaxRecvMsgSize = "NB_MANAGEMENT_GRPC_MAX_MSG_SIZE"
 
+	// defaultMaxRecvMsgSize is the max gRPC receive message size used for the
+	// management client connection when EnvMaxRecvMsgSize is unset or invalid.
+	// It overrides the gRPC library default of 4 MB.
+	defaultMaxRecvMsgSize = 1024 * 1024 * 16
+
 	errMsgMgmtPublicKey    = "failed getting Management Service public key: %s"
 	errMsgNoMgmtConnection = "no connection to management"
 )
@@ -84,22 +89,22 @@ type ExposeResponse struct {
 }
 
 // MaxRecvMsgSize returns the configured max gRPC receive message size from
-// the environment, or 0 if unset (which uses the gRPC default of 4 MB).
+// the environment, or defaultMaxRecvMsgSize (16 MB) if unset or invalid.
 func MaxRecvMsgSize() int {
 	val := os.Getenv(EnvMaxRecvMsgSize)
 	if val == "" {
-		return 0
+		return defaultMaxRecvMsgSize
 	}
 
 	size, err := strconv.Atoi(val)
 	if err != nil {
 		log.Warnf("invalid %s value %q, using default: %v", EnvMaxRecvMsgSize, val, err)
-		return 0
+		return defaultMaxRecvMsgSize
 	}
 
 	if size <= 0 {
 		log.Warnf("invalid %s value %d, must be positive, using default", EnvMaxRecvMsgSize, size)
-		return 0
+		return defaultMaxRecvMsgSize
 	}
 
 	return size

shared/management/client/grpc_test.go

@@ -21,11 +21,11 @@ func TestMaxRecvMsgSize(t *testing.T) {
 		envValue string
 		expected int
 	}{
-		{name: "unset returns 0", envValue: "", expected: 0},
+		{name: "unset returns default", envValue: "", expected: defaultMaxRecvMsgSize},
 		{name: "valid value", envValue: "10485760", expected: 10485760},
-		{name: "non-numeric returns 0", envValue: "abc", expected: 0},
-		{name: "negative returns 0", envValue: "-1", expected: 0},
-		{name: "zero returns 0", envValue: "0", expected: 0},
+		{name: "non-numeric returns default", envValue: "abc", expected: defaultMaxRecvMsgSize},
+		{name: "negative returns default", envValue: "-1", expected: defaultMaxRecvMsgSize},
+		{name: "zero returns default", envValue: "0", expected: defaultMaxRecvMsgSize},
 	}
 
 	for _, tt := range tests {