chore: avoid log files on disk and move them to console for containers

Author: fmenezes

src/common/container.ts

@@ -0,0 +1,24 @@
+import fs from "fs/promises";
+
+export async function detectContainerEnv(): Promise<boolean> {
+    if (process.platform !== "linux") {
+        return false; // we only support linux containers for now
+    }
+
+    if (process.env.container) {
+        return true;
+    }
+
+    const exists = await Promise.all(
+        ["/.dockerenv", "/run/.containerenv", "/var/run/.containerenv"].map(async (file) => {
+            try {
+                await fs.access(file);
+                return true;
+            } catch {
+                return false;
+            }
+        })
+    );
+
+    return exists.includes(true);
+}

src/logger.ts

@@ -180,11 +180,16 @@ class CompositeLogger extends LoggerBase {
 const logger = new CompositeLogger();
 export default logger;
 
-export async function initializeLogger(server: McpServer, logPath: string): Promise<LoggerBase> {
+export async function setStdioPreset(server: McpServer, logPath: string): Promise<void> {
     const diskLogger = await DiskLogger.fromPath(logPath);
     const mcpLogger = new McpLogger(server);
 
     logger.setLoggers(mcpLogger, diskLogger);
+}
+
+export function setDockerPreset(server: McpServer): void {
+    const mcpLogger = new McpLogger(server);
+    const consoleLogger = new ConsoleLogger();
 
-    return logger;
+    logger.setLoggers(mcpLogger, consoleLogger);
 }

src/server.ts

@@ -3,14 +3,15 @@ import { Session } from "./session.js";
 import { Transport } from "@modelcontextprotocol/sdk/shared/transport.js";
 import { AtlasTools } from "./tools/atlas/tools.js";
 import { MongoDbTools } from "./tools/mongodb/tools.js";
-import logger, { initializeLogger, LogId } from "./logger.js";
+import logger, { setStdioPreset, setDockerPreset, LogId } from "./logger.js";
 import { ObjectId } from "mongodb";
 import { Telemetry } from "./telemetry/telemetry.js";
 import { UserConfig } from "./config.js";
 import { type ServerEvent } from "./telemetry/types.js";
 import { type ServerCommand } from "./telemetry/types.js";
 import { CallToolRequestSchema, CallToolResult } from "@modelcontextprotocol/sdk/types.js";
 import assert from "assert";
+import { detectContainerEnv } from "./common/container.js";
 
 export interface ServerOptions {
     session: Session;
@@ -63,7 +64,13 @@ export class Server {
             return existingHandler(request, extra);
         });
 
-        await initializeLogger(this.mcpServer, this.userConfig.logPath);
+        const containerEnv = await detectContainerEnv();
+
+        if (containerEnv) {
+            setDockerPreset(this.mcpServer);
+        } else {
+            await setStdioPreset(this.mcpServer, this.userConfig.logPath);
+        }
 
         await this.mcpServer.connect(transport);
 

src/telemetry/telemetry.ts

@@ -7,7 +7,7 @@ import { MACHINE_METADATA } from "./constants.js";
 import { EventCache } from "./eventCache.js";
 import nodeMachineId from "node-machine-id";
 import { getDeviceId } from "@mongodb-js/device-id";
-import fs from "fs/promises";
+import { detectContainerEnv } from "../common/container.js";
 
 type EventResult = {
     success: boolean;
@@ -53,29 +53,6 @@ export class Telemetry {
         return instance;
     }
 
-    private async isContainerEnv(): Promise<boolean> {
-        if (process.platform !== "linux") {
-            return false; // we only support linux containers for now
-        }
-
-        if (process.env.container) {
-            return true;
-        }
-
-        const exists = await Promise.all(
-            ["/.dockerenv", "/run/.containerenv", "/var/run/.containerenv"].map(async (file) => {
-                try {
-                    await fs.access(file);
-                    return true;
-                } catch {
-                    return false;
-                }
-            })
-        );
-
-        return exists.includes(true);
-    }
-
     private async setup(): Promise<void> {
         if (!this.isTelemetryEnabled()) {
             return;
@@ -98,7 +75,7 @@ export class Telemetry {
                 },
                 abortSignal: this.deviceIdAbortController.signal,
             }),
-            this.isContainerEnv(),
+            detectContainerEnv(),
         ]);
 
         const [deviceId, containerEnv] = await this.setupPromise;