fix: start mcp even if connection fails - [MCP-140] (#503)

Author: blva

src/common/logger.ts

@@ -41,6 +41,7 @@ export const LogId = {
 
     mongodbConnectFailure: mongoLogId(1_004_001),
     mongodbDisconnectFailure: mongoLogId(1_004_002),
+    mongodbConnectTry: mongoLogId(1_004_003),
 
     toolUpdateFailure: mongoLogId(1_005_001),
     resourceUpdateFailure: mongoLogId(1_005_002),

src/server.ts

@@ -20,6 +20,7 @@ import {
 import assert from "assert";
 import type { ToolBase } from "./tools/tool.js";
 import { validateConnectionString } from "./helpers/connectionOptions.js";
+import { packageInfo } from "./common/packageInfo.js";
 
 export interface ServerOptions {
     session: Session;
@@ -119,11 +120,10 @@ export class Server {
             this.session.setMcpClient(this.mcpServer.server.getClientVersion());
             // Placed here to start the connection to the config connection string as soon as the server is initialized.
             void this.connectToConfigConnectionString();
-
             this.session.logger.info({
                 id: LogId.serverInitialized,
                 context: "server",
-                message: `Server started with transport ${transport.constructor.name} and agent runner ${this.session.mcpClient?.name}`,
+                message: `Server with version ${packageInfo.version} started with transport ${transport.constructor.name} and agent runner ${JSON.stringify(this.session.mcpClient)}`,
             });
 
             this.emitServerEvent("start", Date.now() - this.startTime);
@@ -244,15 +244,21 @@ export class Server {
     private async connectToConfigConnectionString(): Promise<void> {
         if (this.userConfig.connectionString) {
             try {
+                this.session.logger.info({
+                    id: LogId.mongodbConnectTry,
+                    context: "server",
+                    message: `Detected a MongoDB connection string in the configuration, trying to connect...`,
+                });
                 await this.session.connectToMongoDB({
                     connectionString: this.userConfig.connectionString,
                 });
             } catch (error) {
-                console.error(
-                    "Failed to connect to MongoDB instance using the connection string from the config: ",
-                    error
-                );
-                throw new Error("Failed to connect to MongoDB instance using the connection string from the config");
+                // We don't throw an error here because we want to allow the server to start even if the connection string is invalid.
+                this.session.logger.error({
+                    id: LogId.mongodbConnectFailure,
+                    context: "server",
+                    message: `Failed to connect to MongoDB instance using the connection string from the config: ${error instanceof Error ? error.message : String(error)}`,
+                });
             }
         }
     }