LogLayer

Linked Log Level Manager ​

NPM Version

Log Level Manager Source

A log level manager that keeps log levels synchronized between parent and children. Parent and child changes affect each other bidirectionally. Changes only apply to a parent and their children (not separate instances).

Installation ​

bash
npm install @loglayer/log-level-manager-linked
bash
yarn add @loglayer/log-level-manager-linked
bash
pnpm add @loglayer/log-level-manager-linked

Usage ​

typescript
import { LogLayer, ConsoleTransport, LogLevel } from "loglayer";
import { LinkedLogLevelManager } from '@loglayer/log-level-manager-linked';

const parentLog = new LogLayer({
  transport: new ConsoleTransport({
    logger: console
  }),
}).withLogLevelManager(new LinkedLogLevelManager());

const childLog = parentLog.child();

// Parent changes affect children
parentLog.setLevel(LogLevel.warn);

parentLog.info('This will not be logged'); // Not logged
childLog.info('This will not be logged'); // Not logged (affected by parent)

// Child changes also affect parent
childLog.setLevel(LogLevel.debug);

parentLog.debug('This will be logged'); // Logged (affected by child)
childLog.debug('This will be logged'); // Logged (child changed to debug)

Nested Children ​

typescript
import { LogLayer, ConsoleTransport, LogLevel } from "loglayer";
import { LinkedLogLevelManager } from '@loglayer/log-level-manager-linked';

const parentLog = new LogLayer({
  transport: new ConsoleTransport({
    logger: console
  }),
}).withLogLevelManager(new LinkedLogLevelManager());

const childLog = parentLog.child();
const grandchildLog = childLog.child();

// Parent changes affect all descendants
parentLog.setLevel(LogLevel.error);

parentLog.warn('This will not be logged'); // Not logged
childLog.warn('This will not be logged'); // Not logged (affected by parent)
grandchildLog.warn('This will not be logged'); // Not logged (affected by parent)

// Grandchild changes affect all ancestors
grandchildLog.setLevel(LogLevel.debug);

parentLog.debug('This will be logged'); // Logged (affected by grandchild)
childLog.debug('This will be logged'); // Logged (affected by grandchild)
grandchildLog.debug('This will be logged'); // Logged (grandchild changed to debug)

Behavior ​

  • Bidirectional Propagation: Parent changes propagate to all children, and child changes propagate to the parent and all siblings
  • Hierarchical: Changes apply only within a parent-child hierarchy, not across separate logger instances
  • Shared Container: All linked managers in a hierarchy share the same log level container, ensuring immediate synchronization

Use Cases ​

  • Tightly Coupled Modules: When you want log levels to be synchronized across a module hierarchy where any change should affect all related loggers
  • Shared Configuration: When you need a single source of truth for log levels across a parent-child relationship
  • Dynamic Log Level Control: When you want to be able to change log levels from any logger in the hierarchy and have it affect all others