Financial-Times / n-auto-metrics

import { getMetricsInstance } from './init';

export const createEventMetrics = ({ service, operation, action }) => {

	const metrics = getMetricsInstance();

	if (metrics === undefined) {

		throw Error(`auto metrics instance needs to be initialised first`);

	}

	const serviceRoot = `service.${service}.action.${action}`;

	const operationRoot = `operation.${operation}.action.${action}`;

	const countOne = path => {

		metrics.count(`${serviceRoot}.${path}`, 1);

		metrics.count(`${operationRoot}.${path}`, 1);

	};

	return {

		start: () => countOne('state.start'),

		success: () => countOne('state.success'),

		failure: e => {

			countOne(`state.failure.category.${e.category}.status.${e.status}`);

			countOne(`state.failure.category.${e.category}.type.${e.type}`);

		},

	};

};

export const metricsEvent = ({ service, operation, action }) => {

	const event = createEventMetrics({ service, operation, action });

	event.start();

	return event;

};