pip-services3-components-node/src/count/ICounters.ts

Component definitions for Pip.Services in Node.js

/** @module count */
import { CounterTiming } from './CounterTiming';

/**
 * Interface for performance counters that measure execution metrics.
 * 
 * The performance counters measure how code is performing:
 * how fast or slow, how many transactions performed, how many objects
 * are stored, what was the latest transaction time and so on.
 * 
 * They are critical to monitor and improve performance, scalability
 * and reliability of code in production. 
 */
export interface ICounters {
	/**
	 * Begins measurement of execution time interval.
	 * It returns [[CounterTiming]] object which has to be called at
	 * [[CounterTiming.endTiming]] to end the measurement and update the counter.
	 * 
	 * @param name 	a counter name of Interval type.
	 * @returns a [[CounterTiming]] callback object to end timing.
	 */
	beginTiming(name: string) : CounterTiming;
	
	/**
	 * Calculates min/average/max statistics based on the current and previous values.
	 * 
	 * @param name 		a counter name of Statistics type
	 * @param value		a value to update statistics
	 */
	stats(name: string, value: number) : void;

	/**
	 * Records the last calculated measurement value.
	 * 
	 * Usually this method is used by metrics calculated
	 * externally.
	 * 
	 * @param name 		a counter name of Last type.
	 * @param value		a last value to record.
	 */
	last(name: string, value: number) : void;

	/**
	 * Records the current time as a timestamp.
	 * 
	 * @param name 		a counter name of Timestamp type.
	 */
	timestampNow(name: string) : void;

	/**
	 * Records the given timestamp.
	 * 
	 * @param name 		a counter name of Timestamp type.
	 * @param value		a timestamp to record.
	 */
	timestamp(name: string, value: Date) : void;
	
	/**
	 * Increments counter by 1.
	 * 
	 * @param name 		a counter name of Increment type.
	 */
	incrementOne(name: string) : void;

	/**
	 * Increments counter by given value.
	 * 
	 * @param name 		a counter name of Increment type.
	 * @param value		a value to add to the counter.
	 */
	increment(name: string, value: number) : void;
}