pip-services3-components-node/src/log/CompositeLogger.ts

Component definitions for Pip.Services in Node.js

/** @module log */
import { IReferences } from 'pip-services3-commons-node';
import { IReferenceable } from 'pip-services3-commons-node';
import { Descriptor } from 'pip-services3-commons-node';

import { ILogger } from './ILogger';
import { Logger } from './Logger';
import { LogLevel } from './LogLevel';

/**
 * Aggregates all loggers from component references under a single component.
 * 
 * It allows to log messages and conveniently send them to multiple destinations. 
 * 
 * ### References ###
 * 
 * - <code>\*:logger:\*:\*:1.0</code> 	(optional) [[ILogger]] components to pass log messages
 * 
 * @see [[ILogger]]
 * 
 * ### Example ###
 * 
 *     class MyComponent implements IConfigurable, IReferenceable {
 *         private _logger: CompositeLogger = new CompositeLogger();
 *     
 *         public configure(config: ConfigParams): void {
 *             this._logger.configure(config);
 *             ...
 *         }
 *     
 *         public setReferences(references: IReferences): void {
 *             this._logger.setReferences(references);
 *             ...
 *         }
 *     
 *         public myMethod(string correlationId): void {
 *             this._logger.debug(correlationId, "Called method mycomponent.mymethod");
 *             ...
 *         }
 *     }
 * 
 */
export class CompositeLogger extends Logger implements IReferenceable {
	private readonly _loggers: ILogger[] = [];

	/**
     * Creates a new instance of the logger.
     * 
	 * @param references 	references to locate the component dependencies. 
     */
	public constructor(references: IReferences = null) {
		super();

		if (references)
			this.setReferences(references);
	}

	/**
	 * Sets references to dependent components.
	 * 
	 * @param references 	references to locate the component dependencies. 
     */
	public setReferences(references: IReferences): void {
		super.setReferences(references);

		let loggers: any[] = references.getOptional<any>(new Descriptor(null, "logger", null, null, null));
        for (var i = 0; i < loggers.length; i++) {
            let logger: ILogger = loggers[i];

			// Todo: This doesn't work in TS. Redo...
            if (logger != this as ILogger)
                this._loggers.push(logger);
        }
	}

	/**
     * Writes a log message to the logger destination(s).
     * 
     * @param level             a log level.
     * @param correlationId     (optional) transaction id to trace execution through call chain.
     * @param error             an error object associated with this message.
     * @param message           a human-readable message to log.
	 */
	protected write(level: LogLevel, correlationId: string, error: Error, message: string): void {
		for (let index = 0; index < this._loggers.length; index++) 
			this._loggers[index].log(level, correlationId, error, message);
	}
}