feat: basic logger

Author: zcaceres

TODO.md

@@ -1,7 +1,11 @@
 ## TODO
 
 NEXT:
-- Add error to make sure people don't pass objects as args to the functions that are decorated. This is critical.
+- Logging
+  - configurable logger class w/log levels
+  - serializes to client
+  - on a context object
+- Add error to make sure people don't pass objects as args to the functions that are decorated. This is critical for the experimental API
 - Prompt in theory accepts inputs by the TS types don't suggest it can and it doesn't seem to share them.
 - Conversion and formatting of messages and responses
   - What are the supported data types

lib/EasyMCP.ts

@@ -32,11 +32,15 @@ import {
   type ReadResourceResult,
   type Root,
   type ServerCapabilities,
+  LoggingMessageNotificationSchema,
+  LoggingLevelSchema,
+  type LoggingLevel,
 } from "@modelcontextprotocol/sdk/types.js";
 import ToolManager from "./ToolManager";
 import PromptManager from "./PromptManager";
 import RootsManager from "./RootsManager";
 import { metadataKey } from "./MagicConfig";
+import LogFormatter from "./LogFormatter";
 
 class BaseMCP {
   name: string;
@@ -250,6 +254,17 @@ class BaseMCP {
     console.log("Registered ListRoots endpoint");
   }
 
+  sendLog({ level, message }: { level: LoggingLevel; message: string }) {
+    if (!this.server) {
+      throw new Error("Server not initialized. Call serve() first.");
+    }
+
+    this.server.sendLoggingMessage({
+      level,
+      message: LogFormatter.format(level, message),
+    });
+  }
+
   static create(name: string, opts: ServerOptions) {
     return new BaseMCP(name, opts);
   }

lib/LogFormatter.ts

@@ -0,0 +1,65 @@
+import type { LoggingLevel } from "@modelcontextprotocol/sdk/types.js";
+
+/**
+ * Prefixes messages with their log level
+ */
+export default class LogFormatter {
+  static format(level: LoggingLevel, message: string): string {
+    switch (level) {
+      case "debug":
+        return this.debug(message);
+      case "info":
+        return this.info(message);
+      case "warning":
+        return this.warning(message);
+      case "error":
+        return this.error(message);
+      case "notice":
+        return this.notice(message);
+      case "critical":
+        return this.critical(message);
+      case "alert":
+        return this.alert(message);
+      case "emergency":
+        return this.emergency(message);
+      default:
+        console.warn(
+          "Invalid log level passed to LogFormatter. This should never happen.",
+          level,
+        );
+        return message;
+    }
+  }
+
+  private static debug(message: string) {
+    return "debug: " + message;
+  }
+
+  private static notice(message: string) {
+    return "notice: " + message;
+  }
+
+  private static critical(message: string) {
+    return "critical: " + message;
+  }
+
+  private static alert(message: string) {
+    return "alert: " + message;
+  }
+
+  private static emergency(message: string) {
+    return "emergency: " + message;
+  }
+
+  private static info(message: string) {
+    return "info: " + message;
+  }
+
+  private static warning(message: string) {
+    return "warning: " + message;
+  }
+
+  private static error(message: string) {
+    return "error: " + message;
+  }
+}