request logger

Author: enisdenjo

packages/logger/package.json

@@ -29,6 +29,16 @@
         "default": "./dist/index.js"
       }
     },
+    "./request": {
+      "require": {
+        "types": "./dist/request.d.cts",
+        "default": "./dist/request.cjs"
+      },
+      "import": {
+        "types": "./dist/request.d.ts",
+        "default": "./dist/request.js"
+      }
+    },
     "./package.json": "./package.json"
   },
   "files": [

packages/logger/src/Logger.ts

@@ -66,14 +66,29 @@ export class Logger implements LogWriter {
     this.#writers = opts.writers ?? [new ConsoleLogWriter()];
   }
 
+  /** The prefix that's prepended to each log message. */
   public get prefix() {
     return this.#prefix;
   }
 
+  /**
+   * The attributes that are added to each log. If the log itself contains
+   * attributes with keys existing in {@link attrs}, the log's attributes will
+   * override.
+   */
+  public get attrs() {
+    return this.#attrs;
+  }
+
+  /** The current {@link LogLevel} of the logger. You can change the level using the {@link setLevel} method. */
   public get level() {
     return typeof this.#level === 'function' ? this.#level() : this.#level;
   }
 
+  /**
+   * Sets the new {@link LogLevel} of the logger. All subsequent logs, and {@link child child loggers} whose
+   * level did not change, will respect the new level.
+   */
   public setLevel(level: MaybeLazy<LogLevel | false>) {
     this.#level = level;
   }

packages/logger/src/request.ts

@@ -0,0 +1,55 @@
+import { Logger } from './Logger';
+
+// TODO: write tests
+
+export const requestIdByRequest = new WeakMap<Request, string>();
+
+/** The getter function that extracts the requestID from the {@link request} or creates a new one if none-exist. */
+export type GetRequestID = (request: Request) => string;
+
+/**
+ * Creates a child {@link Logger} under the {@link log given logger} for the {@link request}.
+ *
+ * Request's ID will be stored in the {@link requestIdByRequest} weak map; meaning, all
+ * subsequent calls to this function with the same {@link request} will return the same ID.
+ *
+ * The {@link getId} argument will be used to create a new ID if the {@link request} does not
+ * have one. The convention is to the `X-Request-ID` header or create a new ID which is an
+ * UUID v4.
+ *
+ * On the other hand, if the {@link getId} argument is omitted, the {@link requestIdByRequest} weak
+ * map will be looked up, and if there is no ID stored for the {@link request} - the function
+ * will not attempt to create a new ID and will just return the same {@link log logger}.
+ *
+ * The request ID will be added to the logger attributes under the `requestId` key and
+ * will be logged in every subsequent log.
+ */
+export function loggerForRequest(log: Logger, request: Request): Logger;
+export function loggerForRequest(
+  log: Logger,
+  request: Request,
+  getId: GetRequestID,
+): Logger;
+export function loggerForRequest(
+  log: Logger,
+  request: Request,
+  getId?: GetRequestID,
+): Logger {
+  let requestId = requestIdByRequest.get(request);
+  if (!requestId) {
+    if (getId === undefined) {
+      return log;
+    }
+    requestId = getId(request);
+    requestIdByRequest.set(request, requestId);
+  }
+  if (
+    log.attrs &&
+    'requestId' in log.attrs &&
+    log.attrs['requestId'] === requestId
+  ) {
+    // this logger is already a child that contains this request id, no need to create a new one
+    return log;
+  }
+  return log.child({ requestId });
+}

tsconfig.json

@@ -62,6 +62,7 @@
       "@graphql-tools/wrap": ["./packages/wrap/src/index.ts"],
       "@graphql-tools/executor-*": ["./packages/executors/*/src/index.ts"],
       "@graphql-hive/logger": ["./packages/logger/src/index.ts"],
+      "@graphql-hive/logger/request": ["./packages/logger/src/request.ts"],
       "@graphql-hive/logger-json": ["./packages/logger-json/src/index.ts"],
       "@graphql-hive/logger-winston": [
         "./packages/logger-winston/src/index.ts"