Inherit methodFactory extensions from the parent to the child loggers. (#4809)

* use methodFactory extensions from the rootLogger in child loggers.

* use simple method factory copy AND `childLogger.setLevel(childLogger.getLevel());`
This is the important part that actually registers the new methods.

* add comments and  find a way to make it clearer that the types are correct.

* review

* additionally fix MatrixRTCSessionManager being initialized before the extension is in place.

* Add comment to clarify order of log extensions and creating childs.

* review

* Set "loglevel" min version to guarantee access to `logger.rebuild`

src/logger.ts

@@ -34,6 +34,11 @@ export interface Logger extends BaseLogger {
     /**
      * Create a child logger.
      *
+     * This child will use the `methodFactory` of the parent, so any log extensions applied to the parent
+     * at the time of calling `getChild` will be applied to the child as well.
+     * It will NOT apply changes to the parent's `methodFactory` after the child was created.
+     * Those changes need to be applied to the child manually.
+     *
      * @param namespace - name to add to the current logger to generate the child. Some implementations of `Logger`
      *    use this as a prefix; others use a different mechanism.
      */
@@ -128,14 +133,24 @@ interface PrefixedLogger extends loglevel.Logger, LoggerWithLogMethod {
  *
  * @param prefix Prefix to add to each logged line. If undefined, no prefix will be added.
  */
-function getPrefixedLogger(prefix?: string): LoggerWithLogMethod {
+function getPrefixedLogger(prefix?: string): PrefixedLogger {
     const loggerName = DEFAULT_NAMESPACE + (prefix === undefined ? "" : `-${prefix}`);
     const prefixLogger = loglevel.getLogger(loggerName) as PrefixedLogger;
 
     if (prefixLogger.getChild === undefined) {
         // This is a new loglevel Logger which has not been turned into a PrefixedLogger yet.
         prefixLogger.prefix = prefix;
-        prefixLogger.getChild = (childPrefix): Logger => getPrefixedLogger((prefix ?? "") + childPrefix);
+        prefixLogger.getChild = (childPrefix): Logger => {
+            // create the new child logger
+            const childLogger = getPrefixedLogger((prefix ?? "") + childPrefix);
+            // Assign the methodFactory from the parent logger.
+            // This is useful if we add extensions to the parent logger that modifies
+            // its methodFactory. (An example extension is: storing each log to a rageshake db)
+            childLogger.methodFactory = prefixLogger.methodFactory;
+            // Rebuild the child logger with the new methodFactory.
+            childLogger.rebuild();
+            return childLogger;
+        };
         prefixLogger.setLevel(loglevel.levels.DEBUG, false);
     }
 
@@ -146,7 +161,7 @@ function getPrefixedLogger(prefix?: string): LoggerWithLogMethod {
  * Drop-in replacement for `console` using {@link https://www.npmjs.com/package/loglevel|loglevel}.
  * Can be tailored down to specific use cases if needed.
  */
-export const logger = getPrefixedLogger();
+export const logger = getPrefixedLogger() as LoggerWithLogMethod;
 
 /**
  * A "span" for grouping related log lines together.

src/matrixrtc/MatrixRTCSessionManager.ts

@@ -14,7 +14,7 @@ See the License for the specific language governing permissions and
 limitations under the License.
 */
 
-import { logger as rootLogger } from "../logger.ts";
+import { logger as rootLogger, type Logger } from "../logger.ts";
 import { type MatrixClient, ClientEvent } from "../client.ts";
 import { TypedEventEmitter } from "../models/typed-event-emitter.ts";
 import { type Room } from "../models/room.ts";
@@ -23,8 +23,6 @@ import { type MatrixEvent } from "../models/event.ts";
 import { MatrixRTCSession } from "./MatrixRTCSession.ts";
 import { EventType } from "../@types/event.ts";
 
-const logger = rootLogger.getChild("[MatrixRTCSessionManager]");
-
 export enum MatrixRTCSessionManagerEvents {
     // A member has joined the MatrixRTC session, creating an active session in a room where there wasn't previously
     SessionStarted = "session_started",
@@ -50,8 +48,10 @@ export class MatrixRTCSessionManager extends TypedEventEmitter<MatrixRTCSessionM
     // longer the correct session object for the room.
     private roomSessions = new Map<string, MatrixRTCSession>();
 
+    private logger: Logger;
     public constructor(private client: MatrixClient) {
         super();
+        this.logger = rootLogger.getChild("[MatrixRTCSessionManager]");
     }
 
     public start(): void {
@@ -105,7 +105,7 @@ export class MatrixRTCSessionManager extends TypedEventEmitter<MatrixRTCSessionM
     private onRoomState = (event: MatrixEvent, _state: RoomState): void => {
         const room = this.client.getRoom(event.getRoomId());
         if (!room) {
-            logger.error(`Got room state event for unknown room ${event.getRoomId()}!`);
+            this.logger.error(`Got room state event for unknown room ${event.getRoomId()}!`);
             return;
         }
 
@@ -129,10 +129,10 @@ export class MatrixRTCSessionManager extends TypedEventEmitter<MatrixRTCSessionM
         const nowActive = session.memberships.length > 0;
 
         if (wasActiveAndKnown && !nowActive) {
-            logger.trace(`Session ended for ${room.roomId} (${session.memberships.length} members)`);
+            this.logger.trace(`Session ended for ${room.roomId} (${session.memberships.length} members)`);
             this.emit(MatrixRTCSessionManagerEvents.SessionEnded, room.roomId, this.roomSessions.get(room.roomId)!);
         } else if (!wasActiveAndKnown && nowActive) {
-            logger.trace(`Session started for ${room.roomId} (${session.memberships.length} members)`);
+            this.logger.trace(`Session started for ${room.roomId} (${session.memberships.length} members)`);
             this.emit(MatrixRTCSessionManagerEvents.SessionStarted, room.roomId, this.roomSessions.get(room.roomId)!);
         }
     }