use mcp logger API (#9434)

Co-authored-by: oleina <[email protected]>

Author: antholeole

src/mcp/index.ts

@@ -79,13 +79,6 @@ export class FirebaseMcpServer {
   // logging spec:
   // https://modelcontextprotocol.io/specification/2025-03-26/server/utilities/logging
   currentLogLevel?: LoggingLevel = process.env.FIREBASE_MCP_DEBUG_LOG ? "debug" : undefined;
-  // the api of logging from a consumers perspective looks like `server.logger.warn("my warning")`.
-  public readonly logger = Object.fromEntries(
-    orderedLogLevels.map((logLevel) => [
-      logLevel,
-      (message: unknown) => this.log(logLevel, message),
-    ]),
-  ) as Record<LoggingLevel, (message: unknown) => Promise<void>>;
 
   /** Create a special tracking function to avoid blocking everything on initialization notification. */
   private async trackGA4(
@@ -191,13 +184,13 @@ export class FirebaseMcpServer {
     if (this.cachedProjectDir) return this.cachedProjectDir;
     const storedRoot = this.getStoredClientConfig().projectRoot;
     this.cachedProjectDir = storedRoot || this.startupRoot || process.cwd();
-    this.log("debug", "detected and cached project root: " + this.cachedProjectDir);
+    this.logger.debug(`detected and cached project root: ${this.cachedProjectDir}`);
     return this.cachedProjectDir;
   }
 
   async detectActiveFeatures(): Promise<ServerFeature[]> {
     if (this.detectedFeatures?.length) return this.detectedFeatures; // memoized
-    this.log("debug", "detecting active features of Firebase MCP server...");
+    this.logger.debug("detecting active features of Firebase MCP server...");
     const projectId = (await this.getProjectId()) || "";
     const accountEmail = await this.getAuthenticatedUser();
     const ctx = this._createMcpContext(projectId, accountEmail);
@@ -209,9 +202,8 @@ export class FirebaseMcpServer {
       }),
     );
     this.detectedFeatures = detected.filter((f) => !!f) as ServerFeature[];
-    this.log(
-      "debug",
-      "detected features of Firebase MCP server: " + (this.detectedFeatures.join(", ") || "<none>"),
+    this.logger.debug(
+      `detected features of Firebase MCP server:  ${this.detectedFeatures.join(", ") || "<none>"}`,
     );
     return this.detectedFeatures;
   }
@@ -295,12 +287,12 @@ export class FirebaseMcpServer {
 
   async getAuthenticatedUser(skipAutoAuth: boolean = false): Promise<string | null> {
     try {
-      this.log("debug", `calling requireAuth`);
+      this.logger.debug("calling requireAuth");
       const email = await requireAuth(await this.resolveOptions(), skipAutoAuth);
-      this.log("debug", `detected authenticated account: ${email || "<none>"}`);
+      this.logger.debug(`detected authenticated account: ${email || "<none>"}`);
       return email ?? (skipAutoAuth ? null : "Application Default Credentials");
     } catch (e) {
-      this.log("debug", `error in requireAuth: ${e}`);
+      this.logger.debug(`error in requireAuth: ${e}`);
       return null;
     }
   }
@@ -330,7 +322,7 @@ export class FirebaseMcpServer {
     const hasActiveProject = !!(await this.getProjectId());
     await this.trackGA4("mcp_list_tools");
     const skipAutoAuthForStudio = isFirebaseStudio();
-    this.log("debug", `skip auto-auth in studio environment: ${skipAutoAuthForStudio}`);
+    this.logger.debug(`skip auto-auth in studio environment: ${skipAutoAuthForStudio}`);
     const availableTools = await this.getAvailableTools();
     return {
       tools: availableTools.map((t) => t.mcp),
@@ -491,35 +483,47 @@ export class FirebaseMcpServer {
     await this.server.connect(transport);
   }
 
-  log(level: LoggingLevel, message: unknown): void {
-    let data = message;
+  get logger() {
+    const logAtLevel = (level: LoggingLevel, message: unknown): void => {
+      let data = message;
 
-    // mcp protocol only takes jsons or it errors; for convienence, format
-    // a a string into a json.
-    if (typeof message === "string") {
-      data = { message };
-    }
+      // mcp protocol only takes jsons or it errors; for convienence, format
+      // a a string into a json.
+      if (typeof message === "string") {
+        data = { message };
+      }
 
-    if (!this.currentLogLevel) {
-      return;
-    }
+      if (!this.currentLogLevel) {
+        return;
+      }
 
-    if (orderedLogLevels.indexOf(this.currentLogLevel) > orderedLogLevels.indexOf(level)) {
-      return;
-    }
+      if (orderedLogLevels.indexOf(this.currentLogLevel) > orderedLogLevels.indexOf(level)) {
+        return;
+      }
 
-    if (this._ready) {
-      // once ready, flush all pending messages before sending the next message
-      // this should only happen during startup
-      while (this._pendingMessages.length) {
-        const message = this._pendingMessages.shift();
-        if (!message) continue;
-        this.server.sendLoggingMessage({ level: message.level, data: message.data });
+      if (this._ready) {
+        // once ready, flush all pending messages before sending the next message
+        // this should only happen during startup
+        while (this._pendingMessages.length) {
+          const message = this._pendingMessages.shift();
+          if (!message) continue;
+          this.server.sendLoggingMessage({
+            level: message.level,
+            data: message.data,
+          });
+        }
+
+        void this.server.sendLoggingMessage({ level, data });
+      } else {
+        this._pendingMessages.push({ level, data });
       }
+    };
 
-      void this.server.sendLoggingMessage({ level, data });
-    } else {
-      this._pendingMessages.push({ level, data });
-    }
+    return Object.fromEntries(
+      orderedLogLevels.map((logLevel) => [
+        logLevel,
+        (message: unknown) => logAtLevel(logLevel, message),
+      ]),
+    ) as Record<LoggingLevel, (message: unknown) => Promise<void>>;
   }
 }

src/mcp/util/apptesting/availability.ts

@@ -15,7 +15,7 @@ export async function isAppTestingAvailable(ctx: McpContext): Promise<boolean> {
   const supportedPlatforms = [Platform.FLUTTER, Platform.ANDROID, Platform.IOS];
 
   if (!platforms.some((p) => supportedPlatforms.includes(p))) {
-    host.log("debug", `Found no supported App Testing platforms.`);
+    host.logger.debug("Found no supported App Testing platforms.");
     return false;
   }
 

src/mcp/util/crashlytics/availability.ts

@@ -7,7 +7,7 @@ import * as path from "path";
  * Returns a function that detects whether Crashlytics is available.
  */
 export async function isCrashlyticsAvailable(ctx: McpContext): Promise<boolean> {
-  ctx.host.log("debug", `Looking for whether crashlytics is installed...`);
+  ctx.host.logger.debug("Looking for whether crashlytics is installed...");
   return await isCrashlyticsInstalled(ctx);
 }
 
@@ -22,25 +22,24 @@ async function isCrashlyticsInstalled(ctx: McpContext): Promise<boolean> {
     !platforms.includes(Platform.ANDROID) &&
     !platforms.includes(Platform.IOS)
   ) {
-    host.log("debug", `Found no supported Crashlytics platforms.`);
+    host.logger.debug("Found no supported Crashlytics platforms.");
     return false;
   }
 
   if (platforms.includes(Platform.FLUTTER) && (await flutterAppUsesCrashlytics(projectDir))) {
-    host.log("debug", `Found Flutter app using Crashlytics`);
+    host.logger.debug("Found Flutter app using Crashlytics");
     return true;
   }
   if (platforms.includes(Platform.ANDROID) && (await androidAppUsesCrashlytics(projectDir))) {
-    host.log("debug", `Found Android app using Crashlytics`);
+    host.logger.debug("Found Android app using Crashlytics");
     return true;
   }
   if (platforms.includes(Platform.IOS) && (await iosAppUsesCrashlytics(projectDir))) {
-    host.log("debug", `Found iOS app using Crashlytics`);
+    host.logger.debug("Found iOS app using Crashlytics");
     return true;
   }
 
-  host.log(
-    "debug",
+  host.logger.debug(
     `Found supported platforms ${JSON.stringify(platforms)}, but did not find a Crashlytics dependency.`,
   );
   return false;