metrics: overlay app metrics over system metrics

This commit is contained in:
Girish Ramakrishnan
2025-07-07 15:53:09 +02:00
parent 369474a0bc
commit 4cf1739604
7 changed files with 242 additions and 159 deletions
+25 -37
View File
@@ -21,21 +21,13 @@ const props = defineProps({
title: String,
subtext: String,
period: Object, // { hours, format, tooltpFormat }
datasetLabels: {
type: Array,
validator: (val) => Array.isArray(val) && val.every(item => typeof item === 'string')
},
datasetColors: {
type: Array,
validator: (val) => Array.isArray(val) && val.every(item => typeof item === 'string')
},
yscale: String, // cpu, memory
memory: Number,
cpuCount: Number,
highMark: Number,
});
function createGraphOptions({ yscale, period, displayLegend, highMark }) {
function createGraphOptions({ yscale, period, highMark }) {
let startTime, endTime, stepSize, count; // x axis configuration values
const now = Date.now();
@@ -54,8 +46,8 @@ function createGraphOptions({ yscale, period, displayLegend, highMark }) {
maintainAspectRatio: false,
plugins: {
legend: {
display: displayLegend,
position: 'bottom'
display: false,
position: 'bottom' // not used, hidden since color code is shown in tooltip
},
tooltip: {
callbacks: {
@@ -121,10 +113,23 @@ function transformData(data) {
return { x, y };
}
function setData(...data) {
for (const [index, items] of data.entries()) {
graph.data.datasets[index].data = items.map(transformData);
function setDatasets(datasets) {
graph.data = { datasets: [] };
for (const dataset of datasets) {
graph.data.datasets.push({
label: dataset.label,
data: dataset.data.map(transformData),
pointRadius: 0,
borderWidth: 1, // https://www.chartjs.org/docs/latest/charts/line.html#line-styling
tension: 0.4,
showLine: true,
fill: true,
color: dataset.color,
stack: dataset.stack || 'stackgroup', // put them all in same stackgroup
});
}
graph.update('none');
}
@@ -140,10 +145,10 @@ function advance() {
graph.update('none');
}
function pushData(...data) {
function pushData(datasetIndex, ...data) {
for (const [index, item] of data.entries()) {
graph.data.datasets[index].data.push(transformData(item));
pruneGraphData(graph.data.datasets[index], graph.options);
graph.data.datasets[datasetIndex+index].data.push(transformData(item));
pruneGraphData(graph.data.datasets[datasetIndex+index], graph.options);
}
graph.update('none');
}
@@ -154,22 +159,6 @@ function onPeriodChanged() {
liveRefreshIntervalId = null;
}
const data = { datasets: [] };
for (const [index, label] of props.datasetLabels.entries()) {
data.datasets.push({
label: label,
data: [],
pointRadius: 0,
borderWidth: 1, // https://www.chartjs.org/docs/latest/charts/line.html#line-styling
tension: 0.4,
showLine: true,
fill: true,
color: props.datasetColors[index],
stack: 'stackgroup' // put them all in same stackgroup
});
}
// CPU and Memory graph have known min/max set and auto-scaling gets disabled
// Disk and Network graphs auto-scale the y values.
@@ -236,12 +225,11 @@ function onPeriodChanged() {
}
// this sets a min 'x' based on current timestamp. so it has to re-created every time the period changes
const graphOptions = createGraphOptions({ yscale, period: props.period, displayLegend: props.datasetLabels.length > 1, highMark });
const graphOptions = createGraphOptions({ yscale, period: props.period, highMark });
if (!graph) {
graph = new Chart(graphNode.value, { type: 'line', data, options: graphOptions });
graph = new Chart(graphNode.value, { type: 'line', data: { datasets: [] }, options: graphOptions });
} else {
graph.data = data;
graph.options = graphOptions;
graph.update('none');
}
@@ -261,7 +249,7 @@ onUnmounted(async function () {
});
defineExpose({
setData,
setDatasets,
pushData,
});
+114 -44
View File
@@ -4,14 +4,16 @@ import { useI18n } from 'vue-i18n';
const i18n = useI18n();
const t = i18n.t;
import { ref, onMounted, onUnmounted, useTemplateRef, nextTick } from 'vue';
import { SingleSelect } from 'pankow';
import { ref, onMounted, onUnmounted, useTemplateRef, nextTick, watch } from 'vue';
import { SingleSelect, MultiSelect } from 'pankow';
import Section from './Section.vue';
import SystemModel from '../models/SystemModel.js';
import { prettyDecimalSize } from 'pankow/utils';
import GraphItem from './GraphItem.vue';
import AppsModel from '../models/AppsModel.js';
const systemModel = SystemModel.create();
const appsModel = AppsModel.create();
const periods = [
{ hours: 0, label: t('app.graphs.period.live'), tickFormat: 'hh:mm A', tooltipFormat: 'hh:mm:ss A' },
@@ -36,73 +38,148 @@ const networkWriteTotal = ref(0);
const blockReadTotal = ref(0);
const blockWriteTotal = ref(0);
const containers = ref([]);
const allContainers = ref([]);
let systemMemory = {};
let systemCpus = {};
let metricStream = null;
async function liveRefresh() {
metricStream = await systemModel.getMetricStream();
const options = {
system: true,
appIds: containers.value.map(c => c.id),
serviceIds: []
};
metricStream = await systemModel.getMetricStream(options);
metricStream.onerror = (error) => console.log('event stream error:', error);
metricStream.onmessage = (message) => {
const data = JSON.parse(message.data);
cpuGraphItem.value.pushData(data.cpu);
memoryGraphItem.value.pushData(data.memory, data.swap);
diskGraphItem.value.pushData(data.blockReadRate, data.blockWriteRate);
networkGraphItem.value.pushData(data.networkReadRate, data.networkWriteRate);
for (const [id, metric] of Object.entries(data)) {
const idx = id !== 'system' ? containers.value.findIndex(c => c.id === id) : containers.value.length;
blockReadTotal.value = prettyDecimalSize(data.blockReadTotal);
blockWriteTotal.value = prettyDecimalSize(data.blockWriteTotal);
networkReadTotal.value = prettyDecimalSize(data.networkReadTotal);
networkWriteTotal.value = prettyDecimalSize(data.networkWriteTotal);
cpuGraphItem.value.pushData(idx, metric.cpu);
memoryGraphItem.value.pushData(idx*2, metric.memory, metric.swap || []); // apps have no swap
diskGraphItem.value.pushData(idx*2, metric.blockReadRate, metric.blockWriteRate);
networkGraphItem.value.pushData(idx*2, metric.networkReadRate, metric.networkWriteRate);
if (id === 'system') {
blockReadTotal.value = prettyDecimalSize(metric.blockReadTotal);
blockWriteTotal.value = prettyDecimalSize(metric.blockWriteTotal);
networkReadTotal.value = prettyDecimalSize(metric.networkReadTotal);
networkWriteTotal.value = prettyDecimalSize(metric.networkWriteTotal);
}
}
};
}
async function onPeriodChange() {
function generateConsistentColors(n, saturation = 90, lightness = 90) {
const baseHue = 204; // from #9ad0f5 → hsl(204,82%,78%)
const colors = [];
const step = 360 / n;
for (let i = 0; i < n; i++) {
const hue = Math.round((baseHue + step * i) % 360); // rotate hue, wrap at 360
colors.push(`hsl(${hue}, ${saturation}%, ${lightness}%)`);
}
return colors;
}
function createDatasets() {
const colors = generateConsistentColors((containers.value.length+1)*2); // 1 for the 'system'
const datasets = {
cpu: [],
memory: [],
disk: [],
network: [],
};
const appIds = containers.value.map(c => c.id);
for (const [idx, id] of appIds.concat(['system']).entries()) { // live stream code depends on this concat order!
const prefix = id === 'system' ? 'System' : containers.value[idx].label;
datasets.cpu.push({ label: `${prefix} CPU`, color: colors[idx*2], stack: `${prefix}-cpu`, data: [] });
datasets.memory.push({ label: `${prefix} Memory`, color: colors[idx*2], stack: `${prefix}-memswap`, data: [] });
datasets.memory.push({ label: `${prefix} Swap`, color: colors[idx*2 + 1], stack: `${prefix}-memswap`, data: [] });
datasets.disk.push({ label: `${prefix} Read`, color: colors[idx*2], stack: `${prefix}-read`, data: [] });
datasets.disk.push({ label: `${prefix} Write`, color: colors[idx*2 + 1], stack: `${prefix}-write`, prefix, data: [] });
datasets.network.push({ label: `${prefix} RX`, color: colors[idx*2], stack: `${prefix}-rx`, data: [] });
datasets.network.push({ label: `${prefix} TX`, color: colors[idx*2 + 1], stack: `${prefix}-tx`, data: [] });
}
return datasets;
}
async function rebuild() {
if (metricStream) {
metricStream.close();
metricStream = null;
}
const datasets = createDatasets();
if (period.value.hours !== 0) {
const options = {
fromSecs: period.value.hours * 60 * 60,
intervalSecs: period.value.intervalSecs,
system: true,
appIds: containers.value.map(c => c.id),
serviceIds: []
};
const [error, metrics] = await systemModel.getMetrics(options);
if (error) return console.error(error);
const appIds = containers.value.map(c => c.id);
for (const [idx, id] of appIds.concat(['system']).entries()) {
if (!metrics[id]) continue;
datasets.cpu[idx].data = metrics[id].cpu;
datasets.memory[idx*2].data = metrics[id].memory;
datasets.memory[idx*2 + 1].data = metrics[id].swap || []; // apps have no swap
datasets.disk[idx*2].data = metrics[id].blockReadRate;
datasets.disk[idx*2 + 1].data = metrics[id].blockWriteRate;
datasets.network[idx*2].data = metrics[id].networkReadRate;
datasets.network[idx*2 + 1].data = metrics[id].networkWriteRate;
}
networkReadTotal.value = prettyDecimalSize(metrics.system.networkReadTotal);
networkWriteTotal.value = prettyDecimalSize(metrics.system.networkWriteTotal);
blockReadTotal.value = prettyDecimalSize(metrics.system.blockReadTotal);
blockWriteTotal.value = prettyDecimalSize(metrics.system.blockWriteTotal);
}
cpuGraphItem.value.setDatasets(datasets.cpu);
memoryGraphItem.value.setDatasets(datasets.memory);
diskGraphItem.value.setDatasets(datasets.disk);
networkGraphItem.value.setDatasets(datasets.network);
if (period.value.hours === 0) return await liveRefresh();
const options = {
fromSecs: period.value.hours * 60 * 60,
intervalSecs: period.value.intervalSecs,
system: true,
appIds: [],
serviceIds: []
};
const [error, metrics] = await systemModel.getMetrics(options);
if (error) return console.error(error);
cpuGraphItem.value.setData(metrics.system.cpu);
memoryGraphItem.value.setData(metrics.system.memory, metrics.system.swap);
diskGraphItem.value.setData(metrics.system.blockReadRate, metrics.system.blockWriteRate);
networkGraphItem.value.setData(metrics.system.networkReadRate, metrics.system.networkWriteRate);
networkReadTotal.value = prettyDecimalSize(metrics.system.networkReadTotal);
networkWriteTotal.value = prettyDecimalSize(metrics.system.networkWriteTotal);
blockReadTotal.value = prettyDecimalSize(metrics.system.blockReadTotal);
blockWriteTotal.value = prettyDecimalSize(metrics.system.blockWriteTotal);
}
onMounted(async () => {
let error, result;
[error, result] = await systemModel.memory();
if (error) return console.error(error);
systemMemory = result;
[error, result] = await systemModel.cpus();
if (error) return console.error(error);
systemCpus = result;
[error, result] = await appsModel.list();
if (error) return console.error(error);
result.forEach(a => a.label = (a.label || a.fqdn));
allContainers.value = result;
containers.value = [];
busy.value = false;
await nextTick();
await onPeriodChange();
await rebuild();
});
onUnmounted(async () => {
@@ -114,7 +191,8 @@ onUnmounted(async () => {
<template>
<Section :title="$t('system.graphs.title')">
<template #header-buttons>
<SingleSelect @select="onPeriodChange()" v-model="period" :options="periods" option-label="label"/>
<MultiSelect @select="rebuild()" v-model="containers" :options="allContainers" option-label="label" :search-threshold="20"/>
<SingleSelect @select="rebuild()" v-model="period" :options="periods" option-label="label"/>
</template>
<div class="graphs" v-if="!busy">
@@ -123,8 +201,6 @@ onUnmounted(async () => {
:subtext='systemCpus.length ? `${systemCpus.length} Core "${systemCpus[0].model}"` : ""'
:period="period"
yscale="cpu"
:dataset-labels="['CPU']"
:dataset-colors="['#9ad0f5']"
:cpu-count="systemCpus.length"
>
</GraphItem>
@@ -134,8 +210,6 @@ onUnmounted(async () => {
:subtext="`RAM: ${prettyDecimalSize(systemMemory.memory)} Swap: ${prettyDecimalSize(systemMemory.swap)}`"
:period="period"
yscale="memory"
:dataset-labels="['Memory', 'Swap']"
:dataset-colors="['#9ad0f5', '#ffb1c1']"
:memory="systemMemory.memory + systemMemory.swap"
>
</GraphItem>
@@ -145,8 +219,6 @@ onUnmounted(async () => {
:subtext="$t('app.graphs.diskIOTotal', { read: blockReadTotal, write: blockWriteTotal })"
:period="period"
yscale="disk"
:dataset-labels="['Read', 'Write']"
:dataset-colors="['#9ad0f5', '#ffb1c1']"
>
</GraphItem>
@@ -155,8 +227,6 @@ onUnmounted(async () => {
:subtext="$t('app.graphs.networkIOTotal', { inbound: networkReadTotal, outbound: networkWriteTotal })"
:period="period"
yscale="network"
:dataset-labels="['RX', 'TX']"
:dataset-colors="['#9ad0f5', '#ffb1c1']"
>
</GraphItem>
</div>
+10 -2
View File
@@ -102,8 +102,16 @@ function create() {
if (error || result.status !== 200) return [error || result];
return [null, result.body];
},
async getMetricStream() {
return new EventSource(`${API_ORIGIN}/api/v1/system/metricstream?access_token=${accessToken}`);
async getMetricStream(options) {
const query = [
['system', String(!!options.system)],
...options.appIds.map(id => ['appId', id]), // multiple appId=xx
...options.serviceIds.map(id => ['serviceId', id]), // multiple serviceId=xx
['access_token', accessToken]
];
const queryString = new URLSearchParams(query).toString();
return new EventSource(`${API_ORIGIN}/api/v1/system/metricstream?${queryString}`);
}
};
}
+83 -71
View File
@@ -1,12 +1,8 @@
'use strict';
exports = module.exports = {
getSystem,
getSystemStream,
getContainer,
getContainerStream,
get,
getStream,
sendToGraphite
};
@@ -22,7 +18,6 @@ const apps = require('./apps.js'),
path = require('path'),
{ Readable } = require('stream'),
safe = require('safetydance'),
services = require('./services.js'),
superagent = require('./superagent.js');
function translateContainerStatsSync(stats) {
@@ -361,7 +356,7 @@ async function readSystemFromGraphite(options) {
// Disk:
// writing: fio --name=rate-test --filename=tempfile --rw=write --bs=4k --ioengine=libaio --rate=20M --size=5000M --runtime=150 --direct=1. test with iotop
// reading: fio --name=rate-test --filename=tempfile --rw=read --bs=4k --ioengine=libaio --rate=20M --size=5000M --runtime=150 --direct=1. test with iotop
async function getSystem(options) {
async function get(options) {
assert.strictEqual(typeof options, 'object');
const result = {};
@@ -379,74 +374,18 @@ async function getSystem(options) {
return result;
}
async function getSystemStream(options) {
assert.strictEqual(typeof options, 'object');
const INTERVAL_MSECS = 1000;
let intervalId = null, oldMetrics = null;
const metricsStream = new Readable({
objectMode: true,
read(/*size*/) { /* ignored, we push via interval */ },
destroy(error, callback) {
clearInterval(intervalId);
callback(error);
}
});
intervalId = setInterval(async () => {
const [error, metrics] = await safe(readSystemMetrics());
if (error) return metricsStream.destroy(error);
const cpuPercent = oldMetrics ? (metrics.userMsecs + metrics.sysMsecs - oldMetrics.userMsecs - oldMetrics.sysMsecs) * 100 / INTERVAL_MSECS : null;
const blockReadRate = oldMetrics ? (metrics.blockRead - oldMetrics.blockRead) / (INTERVAL_MSECS/1000) : null;
const blockWriteRate = oldMetrics ? (metrics.blockWrite - oldMetrics.blockWrite) / (INTERVAL_MSECS/1000) : null;
const networkReadRate = oldMetrics ? (metrics.networkRead - oldMetrics.networkRead) / (INTERVAL_MSECS/1000) : null;
const networkWriteRate = oldMetrics ? (metrics.networkWrite - oldMetrics.networkWrite) / (INTERVAL_MSECS/1000) : null;
oldMetrics = metrics;
const nowSecs = Date.now() / 1000; // to match graphite return value
metricsStream.push({
cpu: [ cpuPercent, nowSecs ],
memory: [ metrics.memoryUsed, nowSecs ],
swap: [ metrics.swapUsed, nowSecs ],
blockReadRate: [ blockReadRate, nowSecs ],
blockWriteRate: [ blockWriteRate, nowSecs ],
blockReadTotal: metrics.blockRead,
blockWriteTotal: metrics.blockWrite,
networkReadRate: [ networkReadRate, nowSecs ],
networkWriteRate: [ networkWriteRate, nowSecs ],
networkReadTotal: metrics.networkRead,
networkWriteTotal: metrics.networkWrite,
});
}, INTERVAL_MSECS);
return metricsStream;
}
async function getContainerStream(name, options) {
async function pipeContainerMetrics(name, metricsStream, ac) {
assert.strictEqual(typeof name, 'string');
assert.strictEqual(typeof options, 'object');
assert.strictEqual(typeof metricsStream, 'object');
assert.strictEqual(typeof ac, 'object');
let oldMetrics = null;
const metricsStream = new Readable({
objectMode: true,
read(/*size*/) { /* ignored, we push via interval */ },
destroy(error, callback) {
statsStream.destroy(); // double destroy is a no-op
callback(error);
}
});
// we used to poll before instead of a stream. but docker caches metrics internally and rate logic has to handle dups
const [error, statsStream] = await safe(docker.getStats(name, { stream: true }));
if (error) throw new Error(`Container stopped or missing: ${error.message}`);
if (error) return; // container stopped or missing, silently ignore
statsStream.on('error', (error) => metricsStream.destroy(error)); // double destroy is a no-op
statsStream.on('error', (error) => debug(error));
statsStream.on('data', (data) => {
const stats = JSON.parse(data.toString('utf8'));
const metrics = translateContainerStatsSync(stats);
@@ -465,7 +404,8 @@ async function getContainerStream(name, options) {
oldMetrics = metrics;
const nowSecs = ts.getTime() / 1000; // conver to secs to match graphite return value
metricsStream.push({
const result = {};
result[name] = {
cpu: [ cpuPercent, nowSecs ],
memory: [ memoryUsed, nowSecs ],
@@ -478,8 +418,80 @@ async function getContainerStream(name, options) {
networkWriteRate: [ networkWriteRate, nowSecs ],
networkReadTotal: metrics.networkRead,
networkWriteTotal: metrics.networkWrite,
});
};
metricsStream.push(result);
});
ac.signal.addEventListener('abort', () => { // there is event.type and ac.signal.reason
statsStream.destroy(ac.signal.reason);
}, { once: true });
}
async function pipeSystemMetrics(metricsStream, ac) {
assert.strictEqual(typeof metricsStream, 'object');
assert.strictEqual(typeof ac, 'object');
const INTERVAL_MSECS = 1000;
let oldMetrics = null;
const intervalId = setInterval(async () => {
const [error, metrics] = await safe(readSystemMetrics());
if (error) return metricsStream.destroy(error);
const cpuPercent = oldMetrics ? (metrics.userMsecs + metrics.sysMsecs - oldMetrics.userMsecs - oldMetrics.sysMsecs) * 100 / INTERVAL_MSECS : null;
const blockReadRate = oldMetrics ? (metrics.blockRead - oldMetrics.blockRead) / (INTERVAL_MSECS/1000) : null;
const blockWriteRate = oldMetrics ? (metrics.blockWrite - oldMetrics.blockWrite) / (INTERVAL_MSECS/1000) : null;
const networkReadRate = oldMetrics ? (metrics.networkRead - oldMetrics.networkRead) / (INTERVAL_MSECS/1000) : null;
const networkWriteRate = oldMetrics ? (metrics.networkWrite - oldMetrics.networkWrite) / (INTERVAL_MSECS/1000) : null;
oldMetrics = metrics;
const nowSecs = Date.now() / 1000; // to match graphite return value
const systemStats = {
cpu: [ cpuPercent, nowSecs ],
memory: [ metrics.memoryUsed, nowSecs ],
swap: [ metrics.swapUsed, nowSecs ],
blockReadRate: [ blockReadRate, nowSecs ],
blockWriteRate: [ blockWriteRate, nowSecs ],
blockReadTotal: metrics.blockRead,
blockWriteTotal: metrics.blockWrite,
networkReadRate: [ networkReadRate, nowSecs ],
networkWriteRate: [ networkWriteRate, nowSecs ],
networkReadTotal: metrics.networkRead,
networkWriteTotal: metrics.networkWrite,
};
metricsStream.push({ system: systemStats });
}, INTERVAL_MSECS);
ac.signal.addEventListener('abort', () => { // there is event.type and ac.signal.reason
clearInterval(intervalId);
}, { once: true });
}
async function getStream(options) {
assert.strictEqual(typeof options, 'object');
const ac = new AbortController();
const metricsStream = new Readable({
objectMode: true,
read(/*size*/) { /* ignored, we push via interval */ },
destroy(error, callback) {
ac.abort(error);
callback(error);
}
});
if (options.system) pipeSystemMetrics(metricsStream, ac);
for (const appId of options.appIds) {
pipeContainerMetrics(appId, metricsStream, ac);
}
for (const serviceId of options.serviceIds) {
pipeContainerMetrics(serviceId, metricsStream, ac);
}
return metricsStream;
}
+2 -2
View File
@@ -1076,7 +1076,7 @@ async function getMetrics(req, res, next) {
const fromSecs = parseInt(req.query.fromSecs);
const intervalSecs = parseInt(req.query.intervalSecs);
const noNullPoints = !!req.query.noNullPoints;
const [error, result] = await safe(metrics.getContainer(req.resources.app.id, { fromSecs, noNullPoints, intervalSecs }));
const [error, result] = await safe(metrics.get({ fromSecs, noNullPoints, intervalSecs, appIds: [req.resources.app.id] }));
if (error) return next(new HttpError(500, error));
next(new HttpSuccess(200, result));
@@ -1085,7 +1085,7 @@ async function getMetrics(req, res, next) {
async function getMetricStream(req, res, next) {
if (req.headers.accept !== 'text/event-stream') return next(new HttpError(400, 'This API call requires EventStream'));
const [error, metricStream] = await safe(metrics.getContainerStream(req.resources.app.id, {}));
const [error, metricStream] = await safe(metrics.getStream(req.resources.app.id, { appIds: [req.resources.app.id] }));
if (error) return next(BoxError.toHttpError(error));
res.writeHead(200, {
+2 -1
View File
@@ -145,7 +145,8 @@ async function getMetrics(req, res, next) {
const fromSecs = parseInt(req.query.fromSecs);
const intervalSecs = parseInt(req.query.intervalSecs);
const noNullPoints = !!req.query.noNullPoints;
const [error, result] = await safe(metrics.getContainer(req.params.service, { fromSecs, intervalSecs, noNullPoints }));
const [error, result] = await safe(metrics.get(req.params.service, { fromSecs, intervalSecs, noNullPoints, serviceIds: [req.params.service] }));
if (error) return next(new HttpError(500, error));
next(new HttpSuccess(200, result));
+6 -2
View File
@@ -129,7 +129,7 @@ async function getMetrics(req, res, next) {
const appIds = 'appId' in req.query ? (Array.isArray(req.query.appId) ? req.query.appId : [ req.query.appId ]) : [];
const serviceIds = 'serviceId' in req.query ? (Array.isArray(req.query.serviceId) ? req.query.serviceId : [ req.query.serviceId ]) : [];
const [error, result] = await safe(metrics.getSystem({ fromSecs, intervalSecs, noNullPoints, system, appIds, serviceIds }));
const [error, result] = await safe(metrics.get({ fromSecs, intervalSecs, noNullPoints, system, appIds, serviceIds }));
if (error) return next(new HttpError(500, error));
next(new HttpSuccess(200, result));
@@ -138,7 +138,11 @@ async function getMetrics(req, res, next) {
async function getMetricStream(req, res, next) {
if (req.headers.accept !== 'text/event-stream') return next(new HttpError(400, 'This API call requires EventStream'));
const [error, metricStream] = await safe(metrics.getSystemStream({}));
const system = req.query.system === 'true';
const appIds = 'appId' in req.query ? (Array.isArray(req.query.appId) ? req.query.appId : [ req.query.appId ]) : [];
const serviceIds = 'serviceId' in req.query ? (Array.isArray(req.query.serviceId) ? req.query.serviceId : [ req.query.serviceId ]) : [];
const [error, metricStream] = await safe(metrics.getStream({ system, appIds, serviceIds }));
if (error) return next(BoxError.toHttpError(error));
res.writeHead(200, {