Merge pull request elizaOS#1415 from 0xCardinalError/multiple_localhosts

fix: Multiple Agents running at the same time on localhost

Author: monilpat

agent/src/index.ts

@@ -60,6 +60,7 @@ import fs from "fs";
 import path from "path";
 import { fileURLToPath } from "url";
 import yargs from "yargs";
+import net from "net";
 
 const __filename = fileURLToPath(import.meta.url); // get the resolved path to the file
 const __dirname = path.dirname(__filename); // get the name of the directory
@@ -692,13 +693,30 @@ async function startAgent(
     }
 }
 
+const checkPortAvailable = (port: number): Promise<boolean> => {
+    return new Promise((resolve) => {
+        const server = net.createServer();
+
+        server.once("error", (err: NodeJS.ErrnoException) => {
+            if (err.code === "EADDRINUSE") {
+                resolve(false);
+            }
+        });
+
+        server.once("listening", () => {
+            server.close();
+            resolve(true);
+        });
+
+        server.listen(port);
+    });
+};
+
 const startAgents = async () => {
     const directClient = new DirectClient();
-    const serverPort = parseInt(settings.SERVER_PORT || "3000");
+    let serverPort = parseInt(settings.SERVER_PORT || "3000");
     const args = parseArguments();
-
     let charactersArg = args.characters || args.character;
-
     let characters = [defaultCharacter];
 
     if (charactersArg) {
@@ -713,19 +731,32 @@ const startAgents = async () => {
         elizaLogger.error("Error starting agents:", error);
     }
 
+    // Find available port
+    while (!(await checkPortAvailable(serverPort))) {
+        elizaLogger.warn(
+            `Port ${serverPort} is in use, trying ${serverPort + 1}`
+        );
+        serverPort++;
+    }
+
     // upload some agent functionality into directClient
     directClient.startAgent = async (character: Character) => {
         // wrap it so we don't have to inject directClient later
         return startAgent(character, directClient);
     };
+
     directClient.start(serverPort);
 
+    if (serverPort !== parseInt(settings.SERVER_PORT || "3000")) {
+        elizaLogger.log(`Server started on alternate port ${serverPort}`);
+    }
+
     elizaLogger.log(
-        "Run `pnpm start:client` to start the client and visit the outputted URL (http://localhost:5173) to chat with your agents"
+        "Run `pnpm start:client` to start the client and visit the outputted URL (http://localhost:5173) to chat with your agents. When running multiple agents, use client with different port `SERVER_PORT=3001 pnpm start:client`"
     );
 };
 
 startAgents().catch((error) => {
     elizaLogger.error("Unhandled error in startAgents:", error);
-    process.exit(1); // Exit the process after logging
+    process.exit(1);
 });