Merge pull request #1057 from bbassie/fix/bounded-send-buffer

Limit unacknowledged messages buffered for a connection

test/integration/link.js

@@ -3,8 +3,9 @@ import events from "node:events";
 import jwt from "jsonwebtoken";
 
 import {
-	TestControlConnector, TestHostConnector, TestControl, url, controlToken,
+	TestControlConnector, TestHostConnector, TestControl, url, controlToken, getControl,
 } from "./index.js";
+import * as lib from "@clusterio/lib";
 import { ConnectionClosed, ProtocolError, PolicyViolation, AuthenticationFailed } from "@clusterio/lib";
 import { slowTest } from "../common.js";
 
@@ -92,6 +93,33 @@ describe("Integration of lib/link", function() {
 		await events.once(controlConnector, "connect");
 	});
 
+	it("should start a new session when the send buffer limit is exceeded", async function() {
+		await getControl().send(new lib.ControllerConfigSetFieldRequest("controller.max_send_buffer_size", "0.01"));
+		try {
+			await controlConnector.connect();
+		} finally {
+			await getControl().send(new lib.ControllerConfigSetFieldRequest("controller.max_send_buffer_size", "64"));
+		}
+
+		// Never acknowledge received messages
+		controlConnector._doHeartbeat = function() {
+			this._sendInternal(new lib.MessageHeartbeat());
+		};
+		let invalidated = false;
+		controlConnector.once("invalidate", () => { invalidated = true; });
+		const connected = events.once(controlConnector, "invalidate").then(
+			() => events.once(controlConnector, "connect")
+		);
+		for (let i = 0; i < 100; i++) {
+			if (invalidated) {
+				break;
+			}
+			await control.send(new lib.ControllerConfigGetRequest()).catch(() => {});
+		}
+		assert(invalidated, "session was not invalidated");
+		await connected;
+	});
+
 	it("should properly close connector if close is called during reconnect wait", async function() {
 		await controlConnector.connect();
 		controlConnector._socket.close(ConnectionClosed.Normal, "Test");

test/lib/link/connector.js

@@ -13,10 +13,11 @@ describe("lib/link/connectors", function() {
 		describe("._dropSendBufferSeq()", function() {
 			beforeEach(function() {
 				testConnector._sendBuffer = [
-					{ seq: 1, type: "test", data: {} },
-					{ seq: 2, type: "test", data: {} },
-					{ seq: 4, type: "test", data: {} },
+					{ seq: 1, text: "a" },
+					{ seq: 2, text: "bb" },
+					{ seq: 4, text: "cccc" },
 				];
+				testConnector._sendBufferSize = 7;
 			});
 			it("should do nothing if passed null", function() {
 				testConnector._dropSendBufferSeq(null);
@@ -25,6 +26,7 @@ describe("lib/link/connectors", function() {
 			it("should drop up to sequence", function() {
 				testConnector._dropSendBufferSeq(2);
 				assert.equal(testConnector._sendBuffer.length, 1, "incorrect number of entries dropped");
+				assert.equal(testConnector._sendBufferSize, 4);
 			});
 			it("should ignore holes", function() {
 				testConnector._dropSendBufferSeq(3);
@@ -61,6 +63,37 @@ describe("lib/link/connectors", function() {
 			});
 		});
 
+		describe("send buffer limit", function() {
+			afterEach(function() {
+				testConnector.maxSendBufferSize = 0;
+				testConnector._closing = false;
+			});
+			it("should keep unacknowledged messages under the limit", function() {
+				testConnector._state = "connected";
+				testConnector._sendBuffer = [];
+				testConnector._sendBufferSize = 0;
+				testConnector._socket.closeCalled = false;
+				testConnector.maxSendBufferSize = 1000;
+				testConnector.send(new lib.MessageHeartbeat(1));
+				assert.equal(testConnector._sendBuffer.length, 1);
+				assert(!testConnector._socket.closeCalled, "Close was called on the socket");
+			});
+			it("should clear the buffer and close when the limit is exceeded", function() {
+				testConnector._state = "connected";
+				testConnector._sendBuffer = [];
+				testConnector._sendBufferSize = 0;
+				testConnector._socket.closeCalled = false;
+				testConnector._socket.sentMessages = [];
+				testConnector.maxSendBufferSize = 30;
+				testConnector.send(new lib.MessageHeartbeat(1));
+				testConnector.send(new lib.MessageHeartbeat(2));
+				assert.equal(testConnector._sendBuffer.length, 0);
+				assert.equal(testConnector._sendBufferSize, 0);
+				assert(testConnector._socket.closeCalled, "Close was not called on the socket");
+				assert.equal(testConnector._socket.sentMessages.length, 1);
+			});
+		});
+
 		describe(".close()", function() {
 			it("should call close", function() {
 				testConnector._socket.closeCalled = false;