const https = require("https"); const dayjs = require("dayjs"); const utc = require("dayjs/plugin/utc"); let timezone = require("dayjs/plugin/timezone"); dayjs.extend(utc); dayjs.extend(timezone); const axios = require("axios"); const { Prometheus } = require("../prometheus"); const { log, UP, DOWN, PENDING, flipStatus, TimeLogger } = require("../../src/util"); const { tcping, ping, dnsResolve, checkCertificate, checkStatusCode, getTotalClientInRoom, setting, errorLog, mqttAsync } = require("../util-server"); const { R } = require("redbean-node"); const { BeanModel } = require("redbean-node/dist/bean-model"); const { Notification } = require("../notification"); const { Proxy } = require("../proxy"); const { demoMode } = require("../config"); const version = require("../../package.json").version; const apicache = require("../modules/apicache"); /** * status: * 0 = DOWN * 1 = UP * 2 = PENDING */ class Monitor extends BeanModel { /** * Return an object that ready to parse to JSON for public * Only show necessary data to public * @returns {Object} */ async toPublicJSON(showTags = false) { let obj = { id: this.id, name: this.name, }; if (showTags) { obj.tags = await this.getTags(); } return obj; } /** * Return a object that ready to parse to JSON * @returns {Object} */ async toJSON(includeSensitiveData = true) { let notificationIDList = {}; let list = await R.find("monitor_notification", " monitor_id = ? ", [ this.id, ]); for (let bean of list) { notificationIDList[bean.notification_id] = true; } const tags = await this.getTags(); let data = { id: this.id, name: this.name, url: this.url, method: this.method, hostname: this.hostname, port: this.port, maxretries: this.maxretries, weight: this.weight, active: this.active, type: this.type, interval: this.interval, retryInterval: this.retryInterval, keyword: this.keyword, expiryNotification: this.isEnabledExpiryNotification(), ignoreTls: this.getIgnoreTls(), upsideDown: this.isUpsideDown(), maxredirects: this.maxredirects, accepted_statuscodes: this.getAcceptedStatuscodes(), dns_resolve_type: this.dns_resolve_type, dns_resolve_server: this.dns_resolve_server, dns_last_result: this.dns_last_result, proxyId: this.proxy_id, notificationIDList, tags: tags, mqttUsername: this.mqttUsername, mqttPassword: this.mqttPassword, mqttTopic: this.mqttTopic, mqttSuccessMessage: this.mqttSuccessMessage }; if (includeSensitiveData) { data = { ...data, headers: this.headers, body: this.body, basic_auth_user: this.basic_auth_user, basic_auth_pass: this.basic_auth_pass, pushToken: this.pushToken, }; } return data; } /** * Get all tags applied to this monitor * @returns {Promise[]>} */ async getTags() { return await R.getAll("SELECT mt.*, tag.name, tag.color FROM monitor_tag mt JOIN tag ON mt.tag_id = tag.id WHERE mt.monitor_id = ?", [ this.id ]); } /** * Encode user and password to Base64 encoding * for HTTP "basic" auth, as per RFC-7617 * @returns {string} */ encodeBase64(user, pass) { return Buffer.from(user + ":" + pass).toString("base64"); } /** * Is the TLS expiry notification enabled? * @returns {boolean} */ isEnabledExpiryNotification() { return Boolean(this.expiryNotification); } /** * Parse to boolean * @returns {boolean} */ getIgnoreTls() { return Boolean(this.ignoreTls); } /** * Parse to boolean * @returns {boolean} */ isUpsideDown() { return Boolean(this.upsideDown); } /** * Get status codes that are acceptable * @returns {Object} */ getAcceptedStatuscodes() { return JSON.parse(this.accepted_statuscodes_json); } /** * Start monitor * @param {Server} io Socket server instance */ start(io) { let previousBeat = null; let retries = 0; let prometheus = new Prometheus(this); const beat = async () => { let beatInterval = this.interval; if (! beatInterval) { beatInterval = 1; } if (demoMode) { if (beatInterval < 20) { console.log("beat interval too low, reset to 20s"); beatInterval = 20; } } // Expose here for prometheus update // undefined if not https let tlsInfo = undefined; if (!previousBeat) { previousBeat = await R.findOne("heartbeat", " monitor_id = ? ORDER BY time DESC", [ this.id, ]); } const isFirstBeat = !previousBeat; let bean = R.dispense("heartbeat"); bean.monitor_id = this.id; bean.time = R.isoDateTime(dayjs.utc()); bean.status = DOWN; if (this.isUpsideDown()) { bean.status = flipStatus(bean.status); } // Duration if (!isFirstBeat) { bean.duration = dayjs(bean.time).diff(dayjs(previousBeat.time), "second"); } else { bean.duration = 0; } try { if (this.type === "http" || this.type === "keyword") { // Do not do any queries/high loading things before the "bean.ping" let startTime = dayjs().valueOf(); // HTTP basic auth let basicAuthHeader = {}; if (this.basic_auth_user) { basicAuthHeader = { "Authorization": "Basic " + this.encodeBase64(this.basic_auth_user, this.basic_auth_pass), }; } const httpsAgentOptions = { maxCachedSessions: 0, // Use Custom agent to disable session reuse (https://github.com/nodejs/node/issues/3940) rejectUnauthorized: !this.getIgnoreTls(), }; log.debug("monitor", `[${this.name}] Prepare Options for axios`); const options = { url: this.url, method: (this.method || "get").toLowerCase(), ...(this.body ? { data: JSON.parse(this.body) } : {}), timeout: this.interval * 1000 * 0.8, headers: { "Accept": "text/html,application/xhtml+xml,application/xml;q=0.9,image/avif,image/webp,image/apng,*/*;q=0.8,application/signed-exchange;v=b3;q=0.9", "User-Agent": "Uptime-Kuma/" + version, ...(this.headers ? JSON.parse(this.headers) : {}), ...(basicAuthHeader), }, maxRedirects: this.maxredirects, validateStatus: (status) => { return checkStatusCode(status, this.getAcceptedStatuscodes()); }, }; if (this.proxy_id) { const proxy = await R.load("proxy", this.proxy_id); if (proxy && proxy.active) { const { httpAgent, httpsAgent } = Proxy.createAgents(proxy, { httpsAgentOptions: httpsAgentOptions, }); options.proxy = false; options.httpAgent = httpAgent; options.httpsAgent = httpsAgent; } } if (!options.httpsAgent) { options.httpsAgent = new https.Agent(httpsAgentOptions); } log.debug("monitor", `[${this.name}] Axios Options: ${JSON.stringify(options)}`); log.debug("monitor", `[${this.name}] Axios Request`); let res = await axios.request(options); bean.msg = `${res.status} - ${res.statusText}`; bean.ping = dayjs().valueOf() - startTime; // Check certificate if https is used let certInfoStartTime = dayjs().valueOf(); if (this.getUrl()?.protocol === "https:") { log.debug("monitor", `[${this.name}] Check cert`); try { let tlsInfoObject = checkCertificate(res); tlsInfo = await this.updateTlsInfo(tlsInfoObject); if (!this.getIgnoreTls() && this.isEnabledExpiryNotification()) { log.debug("monitor", `[${this.name}] call sendCertNotification`); await this.sendCertNotification(tlsInfoObject); } } catch (e) { if (e.message !== "No TLS certificate in response") { log.error("monitor", "Caught error"); log.error("monitor", e.message); } } } if (process.env.TIMELOGGER === "1") { log.debug("monitor", "Cert Info Query Time: " + (dayjs().valueOf() - certInfoStartTime) + "ms"); } if (process.env.UPTIME_KUMA_LOG_RESPONSE_BODY_MONITOR_ID === this.id) { log.info("monitor", res.data); } if (this.type === "http") { bean.status = UP; } else { let data = res.data; // Convert to string for object/array if (typeof data !== "string") { data = JSON.stringify(data); } if (data.includes(this.keyword)) { bean.msg += ", keyword is found"; bean.status = UP; } else { throw new Error(bean.msg + ", but keyword is not found"); } } } else if (this.type === "port") { bean.ping = await tcping(this.hostname, this.port); bean.msg = ""; bean.status = UP; } else if (this.type === "ping") { bean.ping = await ping(this.hostname); bean.msg = ""; bean.status = UP; } else if (this.type === "dns") { let startTime = dayjs().valueOf(); let dnsMessage = ""; let dnsRes = await dnsResolve(this.hostname, this.dns_resolve_server, this.dns_resolve_type); bean.ping = dayjs().valueOf() - startTime; if (this.dns_resolve_type === "A" || this.dns_resolve_type === "AAAA" || this.dns_resolve_type === "TXT") { dnsMessage += "Records: "; dnsMessage += dnsRes.join(" | "); } else if (this.dns_resolve_type === "CNAME" || this.dns_resolve_type === "PTR") { dnsMessage = dnsRes[0]; } else if (this.dns_resolve_type === "CAA") { dnsMessage = dnsRes[0].issue; } else if (this.dns_resolve_type === "MX") { dnsRes.forEach(record => { dnsMessage += `Hostname: ${record.exchange} - Priority: ${record.priority} | `; }); dnsMessage = dnsMessage.slice(0, -2); } else if (this.dns_resolve_type === "NS") { dnsMessage += "Servers: "; dnsMessage += dnsRes.join(" | "); } else if (this.dns_resolve_type === "SOA") { dnsMessage += `NS-Name: ${dnsRes.nsname} | Hostmaster: ${dnsRes.hostmaster} | Serial: ${dnsRes.serial} | Refresh: ${dnsRes.refresh} | Retry: ${dnsRes.retry} | Expire: ${dnsRes.expire} | MinTTL: ${dnsRes.minttl}`; } else if (this.dns_resolve_type === "SRV") { dnsRes.forEach(record => { dnsMessage += `Name: ${record.name} | Port: ${record.port} | Priority: ${record.priority} | Weight: ${record.weight} | `; }); dnsMessage = dnsMessage.slice(0, -2); } if (this.dnsLastResult !== dnsMessage) { R.exec("UPDATE `monitor` SET dns_last_result = ? WHERE id = ? ", [ dnsMessage, this.id ]); } bean.msg = dnsMessage; bean.status = UP; } else if (this.type === "push") { // Type: Push const time = R.isoDateTime(dayjs.utc().subtract(this.interval, "second")); let heartbeatCount = await R.count("heartbeat", " monitor_id = ? AND time > ? ", [ this.id, time ]); log.debug("monitor", "heartbeatCount" + heartbeatCount + " " + time); if (heartbeatCount <= 0) { // Fix #922, since previous heartbeat could be inserted by api, it should get from database previousBeat = await Monitor.getPreviousHeartbeat(this.id); throw new Error("No heartbeat in the time window"); } else { // No need to insert successful heartbeat for push type, so end here retries = 0; this.heartbeatInterval = setTimeout(beat, beatInterval * 1000); return; } } else if (this.type === "steam") { const steamApiUrl = "https://api.steampowered.com/IGameServersService/GetServerList/v1/"; const steamAPIKey = await setting("steamAPIKey"); const filter = `addr\\${this.hostname}:${this.port}`; if (!steamAPIKey) { throw new Error("Steam API Key not found"); } let res = await axios.get(steamApiUrl, { timeout: this.interval * 1000 * 0.8, headers: { "Accept": "*/*", "User-Agent": "Uptime-Kuma/" + version, }, httpsAgent: new https.Agent({ maxCachedSessions: 0, // Use Custom agent to disable session reuse (https://github.com/nodejs/node/issues/3940) rejectUnauthorized: !this.getIgnoreTls(), }), maxRedirects: this.maxredirects, validateStatus: (status) => { return checkStatusCode(status, this.getAcceptedStatuscodes()); }, params: { filter: filter, key: steamAPIKey, } }); if (res.data.response && res.data.response.servers && res.data.response.servers.length > 0) { bean.status = UP; bean.msg = res.data.response.servers[0].name; try { bean.ping = await ping(this.hostname); } catch (_) { } } else { throw new Error("Server not found on Steam"); } } else if (this.type === "mqtt") { bean.msg = await mqttAsync(this.hostname, this.mqttTopic, this.mqttSuccessMessage, { port: this.port, username: this.mqttUsername, password: this.mqttPassword, interval: this.interval, }); bean.status = UP; } else { bean.msg = "Unknown Monitor Type"; bean.status = PENDING; } if (this.isUpsideDown()) { bean.status = flipStatus(bean.status); if (bean.status === DOWN) { throw new Error("Flip UP to DOWN"); } } retries = 0; } catch (error) { bean.msg = error.message; // If UP come in here, it must be upside down mode // Just reset the retries if (this.isUpsideDown() && bean.status === UP) { retries = 0; } else if ((this.maxretries > 0) && (retries < this.maxretries)) { retries++; bean.status = PENDING; } } log.debug("monitor", `[${this.name}] Check isImportant`); let isImportant = Monitor.isImportantBeat(isFirstBeat, previousBeat?.status, bean.status); // Mark as important if status changed, ignore pending pings, // Don't notify if disrupted changes to up if (isImportant) { bean.important = true; log.debug("monitor", `[${this.name}] sendNotification`); await Monitor.sendNotification(isFirstBeat, this, bean); // Clear Status Page Cache log.debug("monitor", `[${this.name}] apicache clear`); apicache.clear(); } else { bean.important = false; } if (bean.status === UP) { log.info("monitor", `Monitor #${this.id} '${this.name}': Successful Response: ${bean.ping} ms | Interval: ${beatInterval} seconds | Type: ${this.type}`); } else if (bean.status === PENDING) { if (this.retryInterval > 0) { beatInterval = this.retryInterval; } log.warn("monitor", `Monitor #${this.id} '${this.name}': Pending: ${bean.msg} | Max retries: ${this.maxretries} | Retry: ${retries} | Retry Interval: ${beatInterval} seconds | Type: ${this.type}`); } else { log.warn("monitor", `Monitor #${this.id} '${this.name}': Failing: ${bean.msg} | Interval: ${beatInterval} seconds | Type: ${this.type}`); } log.debug("monitor", `[${this.name}] Send to socket`); io.to(this.user_id).emit("heartbeat", bean.toJSON()); Monitor.sendStats(io, this.id, this.user_id); log.debug("monitor", `[${this.name}] Store`); await R.store(bean); log.debug("monitor", `[${this.name}] prometheus.update`); prometheus.update(bean, tlsInfo); previousBeat = bean; if (! this.isStop) { log.debug("monitor", `[${this.name}] SetTimeout for next check.`); this.heartbeatInterval = setTimeout(safeBeat, beatInterval * 1000); } else { log.info("monitor", `[${this.name}] isStop = true, no next check.`); } }; /** Get a heartbeat and handle errors */ const safeBeat = async () => { try { await beat(); } catch (e) { console.trace(e); errorLog(e, false); log.error("monitor", "Please report to https://github.com/louislam/uptime-kuma/issues"); if (! this.isStop) { log.info("monitor", "Try to restart the monitor"); this.heartbeatInterval = setTimeout(safeBeat, this.interval * 1000); } } }; // Delay Push Type if (this.type === "push") { setTimeout(() => { safeBeat(); }, this.interval * 1000); } else { safeBeat(); } } /** Stop monitor */ stop() { clearTimeout(this.heartbeatInterval); this.isStop = true; this.prometheus().remove(); } /** * Get a new prometheus instance * @returns {Prometheus} */ prometheus() { return new Prometheus(this); } /** * Helper Method: * returns URL object for further usage * returns null if url is invalid * @returns {(null|URL)} */ getUrl() { try { return new URL(this.url); } catch (_) { return null; } } /** * Store TLS info to database * @param checkCertificateResult * @returns {Promise} */ async updateTlsInfo(checkCertificateResult) { let tlsInfoBean = await R.findOne("monitor_tls_info", "monitor_id = ?", [ this.id, ]); if (tlsInfoBean == null) { tlsInfoBean = R.dispense("monitor_tls_info"); tlsInfoBean.monitor_id = this.id; } else { // Clear sent history if the cert changed. try { let oldCertInfo = JSON.parse(tlsInfoBean.info_json); let isValidObjects = oldCertInfo && oldCertInfo.certInfo && checkCertificateResult && checkCertificateResult.certInfo; if (isValidObjects) { if (oldCertInfo.certInfo.fingerprint256 !== checkCertificateResult.certInfo.fingerprint256) { log.debug("monitor", "Resetting sent_history"); await R.exec("DELETE FROM notification_sent_history WHERE type = 'certificate' AND monitor_id = ?", [ this.id ]); } else { log.debug("monitor", "No need to reset sent_history"); log.debug("monitor", oldCertInfo.certInfo.fingerprint256); log.debug("monitor", checkCertificateResult.certInfo.fingerprint256); } } else { log.debug("monitor", "Not valid object"); } } catch (e) { } } tlsInfoBean.info_json = JSON.stringify(checkCertificateResult); await R.store(tlsInfoBean); return checkCertificateResult; } /** * Send statistics to clients * @param {Server} io Socket server instance * @param {number} monitorID ID of monitor to send * @param {number} userID ID of user to send to */ static async sendStats(io, monitorID, userID) { const hasClients = getTotalClientInRoom(io, userID) > 0; if (hasClients) { await Monitor.sendAvgPing(24, io, monitorID, userID); await Monitor.sendUptime(24, io, monitorID, userID); await Monitor.sendUptime(24 * 30, io, monitorID, userID); await Monitor.sendCertInfo(io, monitorID, userID); } else { log.debug("monitor", "No clients in the room, no need to send stats"); } } /** * Send the average ping to user * @param {number} duration Hours */ static async sendAvgPing(duration, io, monitorID, userID) { const timeLogger = new TimeLogger(); let avgPing = parseInt(await R.getCell(` SELECT AVG(ping) FROM heartbeat WHERE time > DATETIME('now', ? || ' hours') AND ping IS NOT NULL AND monitor_id = ? `, [ -duration, monitorID, ])); timeLogger.print(`[Monitor: ${monitorID}] avgPing`); io.to(userID).emit("avgPing", monitorID, avgPing); } /** * Send certificate information to information * @param {Server} io Socket server instance * @param {number} monitorID ID of monitor to send * @param {number} userID ID of user to send to */ static async sendCertInfo(io, monitorID, userID) { let tlsInfo = await R.findOne("monitor_tls_info", "monitor_id = ?", [ monitorID, ]); if (tlsInfo != null) { io.to(userID).emit("certInfo", monitorID, tlsInfo.info_json); } } /** * Uptime with calculation * Calculation based on: * https://www.uptrends.com/support/kb/reporting/calculation-of-uptime-and-downtime * @param {number} duration Hours * @param {number} monitorID ID of monitor to calculate */ static async calcUptime(duration, monitorID) { const timeLogger = new TimeLogger(); const startTime = R.isoDateTime(dayjs.utc().subtract(duration, "hour")); // Handle if heartbeat duration longer than the target duration // e.g. If the last beat's duration is bigger that the 24hrs window, it will use the duration between the (beat time - window margin) (THEN case in SQL) let result = await R.getRow(` SELECT -- SUM all duration, also trim off the beat out of time window SUM( CASE WHEN (JULIANDAY(\`time\`) - JULIANDAY(?)) * 86400 < duration THEN (JULIANDAY(\`time\`) - JULIANDAY(?)) * 86400 ELSE duration END ) AS total_duration, -- SUM all uptime duration, also trim off the beat out of time window SUM( CASE WHEN (status = 1) THEN CASE WHEN (JULIANDAY(\`time\`) - JULIANDAY(?)) * 86400 < duration THEN (JULIANDAY(\`time\`) - JULIANDAY(?)) * 86400 ELSE duration END END ) AS uptime_duration FROM heartbeat WHERE time > ? AND monitor_id = ? `, [ startTime, startTime, startTime, startTime, startTime, monitorID, ]); timeLogger.print(`[Monitor: ${monitorID}][${duration}] sendUptime`); let totalDuration = result.total_duration; let uptimeDuration = result.uptime_duration; let uptime = 0; if (totalDuration > 0) { uptime = uptimeDuration / totalDuration; if (uptime < 0) { uptime = 0; } } else { // Handle new monitor with only one beat, because the beat's duration = 0 let status = parseInt(await R.getCell("SELECT `status` FROM heartbeat WHERE monitor_id = ?", [monitorID])); if (status === UP) { uptime = 1; } } return uptime; } /** * Send Uptime * @param {number} duration Hours * @param {Server} io Socket server instance * @param {number} monitorID ID of monitor to send * @param {number} userID ID of user to send to */ static async sendUptime(duration, io, monitorID, userID) { const uptime = await this.calcUptime(duration, monitorID); io.to(userID).emit("uptime", monitorID, duration, uptime); } /** * Has status of monitor changed since last beat? * @param {boolean} isFirstBeat Is this the first beat of this monitor? * @param {const} previousBeatStatus Status of the previous beat * @param {const} currentBeatStatus Status of the current beat * @returns {boolean} True if is an important beat else false */ static isImportantBeat(isFirstBeat, previousBeatStatus, currentBeatStatus) { // * ? -> ANY STATUS = important [isFirstBeat] // UP -> PENDING = not important // * UP -> DOWN = important // UP -> UP = not important // PENDING -> PENDING = not important // * PENDING -> DOWN = important // PENDING -> UP = not important // DOWN -> PENDING = this case not exists // DOWN -> DOWN = not important // * DOWN -> UP = important let isImportant = isFirstBeat || (previousBeatStatus === UP && currentBeatStatus === DOWN) || (previousBeatStatus === DOWN && currentBeatStatus === UP) || (previousBeatStatus === PENDING && currentBeatStatus === DOWN); return isImportant; } /** * Send a notification about a monitor * @param {boolean} isFirstBeat Is this beat the first of this monitor? * @param {Monitor} monitor The monitor to send a notificaton about * @param {Bean} bean Status information about monitor */ static async sendNotification(isFirstBeat, monitor, bean) { if (!isFirstBeat || bean.status === DOWN) { const notificationList = await Monitor.getNotificationList(monitor); let text; if (bean.status === UP) { text = "✅ Up"; } else { text = "🔴 Down"; } let msg = `[${monitor.name}] [${text}] ${bean.msg}`; for (let notification of notificationList) { try { await Notification.send(JSON.parse(notification.config), msg, await monitor.toJSON(false), bean.toJSON()); } catch (e) { log.error("monitor", "Cannot send notification to " + notification.name); log.error("monitor", e); } } } } /** * Get list of notification providers for a given monitor * @param {Monitor} monitor Monitor to get notification providers for * @returns {Promise[]>} */ static async getNotificationList(monitor) { let notificationList = await R.getAll("SELECT notification.* FROM notification, monitor_notification WHERE monitor_id = ? AND monitor_notification.notification_id = notification.id ", [ monitor.id, ]); return notificationList; } /** * Send notification about a certificate * @param {Object} tlsInfoObject Information about certificate */ async sendCertNotification(tlsInfoObject) { if (tlsInfoObject && tlsInfoObject.certInfo && tlsInfoObject.certInfo.daysRemaining) { const notificationList = await Monitor.getNotificationList(this); log.debug("monitor", "call sendCertNotificationByTargetDays"); await this.sendCertNotificationByTargetDays(tlsInfoObject.certInfo.daysRemaining, 21, notificationList); await this.sendCertNotificationByTargetDays(tlsInfoObject.certInfo.daysRemaining, 14, notificationList); await this.sendCertNotificationByTargetDays(tlsInfoObject.certInfo.daysRemaining, 7, notificationList); } } /** * Send a certificate notification when certificate expires in less * than target days * @param {number} daysRemaining Number of days remaining on certifcate * @param {number} targetDays Number of days to alert after * @param {LooseObject[]} notificationList List of notification providers * @returns {Promise} */ async sendCertNotificationByTargetDays(daysRemaining, targetDays, notificationList) { if (daysRemaining > targetDays) { log.debug("monitor", `No need to send cert notification. ${daysRemaining} > ${targetDays}`); return; } if (notificationList.length > 0) { let row = await R.getRow("SELECT * FROM notification_sent_history WHERE type = ? AND monitor_id = ? AND days = ?", [ "certificate", this.id, targetDays, ]); // Sent already, no need to send again if (row) { log.debug("monitor", "Sent already, no need to send again"); return; } let sent = false; log.debug("monitor", "Send certificate notification"); for (let notification of notificationList) { try { log.debug("monitor", "Sending to " + notification.name); await Notification.send(JSON.parse(notification.config), `[${this.name}][${this.url}] Certificate will be expired in ${daysRemaining} days`); sent = true; } catch (e) { log.error("monitor", "Cannot send cert notification to " + notification.name); log.error("monitor", e); } } if (sent) { await R.exec("INSERT INTO notification_sent_history (type, monitor_id, days) VALUES(?, ?, ?)", [ "certificate", this.id, targetDays, ]); } } else { log.debug("monitor", "No notification, no need to send cert notification"); } } /** * Get the status of the previous heartbeat * @param {number} monitorID ID of monitor to check * @returns {Promise>} */ static async getPreviousHeartbeat(monitorID) { return await R.getRow(` SELECT status, time FROM heartbeat WHERE id = (select MAX(id) from heartbeat where monitor_id = ?) `, [ monitorID ]); } } module.exports = Monitor;