Kuma/server/prometheus.js

const PrometheusClient = require("prom-client");
const { log } = require("../src/util");

const commonLabels = [
    "monitor_name",
    "monitor_type",
    "monitor_url",
    "monitor_hostname",
    "monitor_port",
    "monitor_tags"
];

const monitorCertDaysRemaining = new PrometheusClient.Gauge({
    name: "monitor_cert_days_remaining",
    help: "The number of days remaining until the certificate expires",
    labelNames: commonLabels
});

const monitorCertIsValid = new PrometheusClient.Gauge({
    name: "monitor_cert_is_valid",
    help: "Is the certificate still valid? (1 = Yes, 0= No)",
    labelNames: commonLabels
});
const monitorResponseTime = new PrometheusClient.Gauge({
    name: "monitor_response_time",
    help: "Monitor Response Time (ms)",
    labelNames: commonLabels
});

const monitorStatus = new PrometheusClient.Gauge({
    name: "monitor_status",
    help: "Monitor Status (1 = UP, 0= DOWN, 2= PENDING, 3= MAINTENANCE)",
    labelNames: commonLabels
});

class Prometheus {
    monitorLabelValues = {};

    /**
     * @param {object} monitor Monitor object to monitor
     * @param {Array<object>} tags Tags to add to the monitor
     */
    constructor(monitor, tags) {
        let sanitizedTags = this.sanitizeTags(tags);

        if (sanitizedTags.length <= 0) {
            sanitizedTags = "null";
        }

        this.monitorLabelValues = {
            monitor_name: monitor.name,
            monitor_type: monitor.type,
            monitor_url: monitor.url,
            monitor_hostname: monitor.hostname,
            monitor_port: monitor.port,
            monitor_tags: sanitizedTags
        };
    }

    /**
     * Sanitize tags to remove non-ASCII characters
     * See https://github.com/louislam/uptime-kuma/pull/4704#issuecomment-2366524692
     * @param {Array<object>} tags The tags to sanitize
     * @returns {*[]} The sanitized tags
     */
    sanitizeTags(tags) {
        const nonAsciiRegex = /[^\x00-\x7F]/g;
        const sanitizedTags = [];
        tags.forEach((tag) => {
            if (tag.name.match(nonAsciiRegex) || tag.value.match(nonAsciiRegex)) {
                // If the tag name or value contains non-ASCII characters, skip it
                return;
            }

            if (tag.value !== "") {
                sanitizedTags.push(tag.name + ":" + tag.value);
                return;
            }

            sanitizedTags.push(tag.name);
        });

        return sanitizedTags;
    }

    /**
     * Update the metrics page
     * @param {object} heartbeat Heartbeat details
     * @param {object} tlsInfo TLS details
     * @returns {void}
     */
    update(heartbeat, tlsInfo) {
        if (typeof tlsInfo !== "undefined") {
            try {
                let isValid;
                if (tlsInfo.valid === true) {
                    isValid = 1;
                } else {
                    isValid = 0;
                }
                monitorCertIsValid.set(this.monitorLabelValues, isValid);
            } catch (e) {
                log.error("prometheus", "Caught error");
                log.error("prometheus", e);
            }

            try {
                if (tlsInfo.certInfo != null) {
                    monitorCertDaysRemaining.set(this.monitorLabelValues, tlsInfo.certInfo.daysRemaining);
                }
            } catch (e) {
                log.error("prometheus", "Caught error");
                log.error("prometheus", e);
            }
        }

        if (heartbeat) {
            try {
                monitorStatus.set(this.monitorLabelValues, heartbeat.status);
            } catch (e) {
                log.error("prometheus", "Caught error");
                log.error("prometheus", e);
            }

            try {
                if (typeof heartbeat.ping === "number") {
                    monitorResponseTime.set(this.monitorLabelValues, heartbeat.ping);
                } else {
                    // Is it good?
                    monitorResponseTime.set(this.monitorLabelValues, -1);
                }
            } catch (e) {
                log.error("prometheus", "Caught error");
                log.error("prometheus", e);
            }
        }
    }

    /**
     * Remove monitor from prometheus
     * @returns {void}
     */
    remove() {
        try {
            monitorCertDaysRemaining.remove(this.monitorLabelValues);
            monitorCertIsValid.remove(this.monitorLabelValues);
            monitorResponseTime.remove(this.monitorLabelValues);
            monitorStatus.remove(this.monitorLabelValues);
        } catch (e) {
            console.error(e);
        }
    }
}

module.exports = {
    Prometheus
};