@mdf.js/service-registry/dist/observability/registries/metrics/MetricsFacade.js

MMS - API - Service Registry

"use strict";
Object.defineProperty(exports, "__esModule", { value: true });
exports.MetricsFacade = void 0;
const tslib_1 = require("tslib");
/**
 * Copyright 2024 Mytra Control S.L. All rights reserved.
 *
 * Use of this source code is governed by an MIT-style license that can be found in the LICENSE file
 * or at https://opensource.org/licenses/MIT.
 */
const core_1 = require("@mdf.js/core");
const logger_1 = require("@mdf.js/logger");
const events_1 = tslib_1.__importDefault(require("events"));
const prom_client_1 = require("prom-client");
const Aggregator_1 = require("./Aggregator");
const Router_1 = require("./Router");
const types_1 = require("./types");
/**
 * MetricsFacade class serves as a facade to simplify metrics management across all services
 * in an application. It leverages the prom-client library for metrics management and the express
 * library to expose these metrics via an HTTP endpoint.
 *
 * It accommodates working in cluster environments by optionally creating a new AggregatorRegistry
 * to hold metrics from all worker nodes, in addition to a separate registry for
 * application-specific metrics and the default prom-client registry. Thus, it can manage up to
 * three different registries:
 *
 * 1. Default prom-client registry for default metrics.
 * 2. Application-specific metrics registry.
 * 3. Cluster-wide metrics registry for environments running in a cluster.
 *
 * Depending on the environment and the node type (primary or worker), it responds to metric
 * requests by merging and presenting metrics from appropriate registries.
 */
class MetricsFacade extends events_1.default {
    /**
     * Create an instance of metrics manager
     * @param options - Configuration options for the metrics manager
     */
    constructor(options) {
        super();
        this.options = options;
        this.logger = (0, logger_1.SetContext)(
        // Stryker disable next-line all
        options.logger || new logger_1.DebugLogger(`mdf:registry:metrics:${this.name}`), this.name, this.componentId);
        this.port = this.getPort(options.isCluster);
        this.aggregator = new Aggregator_1.Aggregator(this.logger, this.port);
        this._router = new Router_1.Router(this.aggregator);
        // Stryker disable next-line all
        this.logger.debug(`Metrics manager created for ${this.name} application`);
    }
    /**
     * Conditionally creates an AggregatorRegistry if the service is running in a cluster.
     * @param isCluster - Boolean indicating if the service is running in cluster mode.
     * @returns An AggregatorRegistry instance or undefined if not in cluster mode.
     */
    getPort(isCluster) {
        if (typeof isCluster === 'boolean' && isCluster) {
            return new prom_client_1.AggregatorRegistry();
        }
        else {
            return undefined;
        }
    }
    /** @returns The application name */
    get name() {
        return this.options.name;
    }
    /** @returns The application identifier */
    get componentId() {
        return this.options.instanceId;
    }
    /** @returns An Express router with access to metrics information */
    get router() {
        return this._router.router;
    }
    /** @returns Links offered by this service */
    get links() {
        return { [`${types_1.METRICS_SERVICE_NAME}`]: `/${types_1.METRICS_SERVICE_NAME}` };
    }
    /** @returns The health status of the component */
    get status() {
        return core_1.Health.STATUS.PASS;
    }
    /** @returns Health checks for this service */
    get checks() {
        return {
            [`${this.name}:metrics`]: [
                {
                    status: this.status,
                    observedUnit: 'metrics',
                    componentId: this.componentId,
                    time: new Date().toISOString(),
                },
            ],
        };
    }
    /**
     * Registers one or multiple services to be monitored.
     * @param services - A single service or an array of services to be registered.
     */
    register(services) {
        this.aggregator.register(services);
        // Stryker disable next-line all
        this.logger.debug(`Service(s) registered in metrics aggregator`);
    }
    /** @returns The registry used by the aggregator */
    get registry() {
        return this.aggregator.registry;
    }
    /** @returns Metrics in text/plain format */
    async metricsText() {
        return this.aggregator.metricsText();
    }
    /** @returns Metrics in JSON format */
    async metricsJSON() {
        return this.aggregator.metricsJSON();
    }
    /**
     * Retrieves a single metric by name.
     * @param name - The name of the metric.
     * @returns The metric or undefined if not found.
     */
    getMetric(name) {
        return this.aggregator.getMetric(name);
    }
    /**
     * Retrieves a single metric value in Prometheus format.
     * @param name - The name of the metric.
     * @returns A promise resolved with the metric value as a string.
     */
    getMetricAsString(name) {
        return this.aggregator.getMetricAsString(name);
    }
    /**
     * Retrieves a single metric value in JSON format.
     * @param name - The name of the metric.
     * @returns A promise resolved with the metric object or undefined if not found.
     */
    async getMetricAsJSON(name) {
        return this.aggregator.getMetricAsJSON(name);
    }
    /** Placeholder for starting the metrics service. */
    async start() {
        // Implementation might be added in future
        this.logger.debug('MetricsFacade start method called.');
    }
    /** Placeholder for stopping the metrics service. */
    async stop() {
        // Implementation might be added in future
        this.logger.debug('MetricsFacade stop method called.');
    }
    /** Clears all metrics from the registry. */
    async close() {
        this.aggregator.clear();
        // Stryker disable next-line all
        this.logger.debug('Metrics cleared from the registry');
    }
}
exports.MetricsFacade = MetricsFacade;
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