From c245a2044ecf5418b8010e3e8340a5899db38cf3 Mon Sep 17 00:00:00 2001
From: Emelia Smith <ThisIsMissEm@users.noreply.github.com>
Date: Mon, 26 Aug 2024 10:08:21 +0200
Subject: [PATCH] Streaming: Refactor to use metrics.$name instead of
destructuring (#31566)
---
streaming/index.js | 53 ++++++++++++++++----------------------------
streaming/metrics.js | 17 ++++++++++++--
2 files changed, 34 insertions(+), 36 deletions(-)
diff --git a/streaming/index.js b/streaming/index.js
index 8f6636217..2267c469c 100644
--- a/streaming/index.js
+++ b/streaming/index.js
@@ -292,6 +292,9 @@ const CHANNEL_NAMES = [
const startServer = async () => {
const pgPool = new pg.Pool(pgConfigFromEnv(process.env));
+
+ const metrics = setupMetrics(CHANNEL_NAMES, pgPool);
+
const server = http.createServer();
const wss = new WebSocketServer({ noServer: true });
@@ -388,16 +391,6 @@ const startServer = async () => {
const redisClient = await createRedisClient(redisConfig);
const { redisPrefix } = redisConfig;
- const metrics = setupMetrics(CHANNEL_NAMES, pgPool);
- // TODO: migrate all metrics to metrics.X.method() instead of just X.method()
- const {
- connectedClients,
- connectedChannels,
- redisSubscriptions,
- redisMessagesReceived,
- messagesSent,
- } = metrics;
-
// When checking metrics in the browser, the favicon is requested this
// prevents the request from falling through to the API Router, which would
// error for this endpoint:
@@ -408,15 +401,7 @@ const startServer = async () => {
res.end('OK');
});
- app.get('/metrics', async (req, res) => {
- try {
- res.set('Content-Type', metrics.register.contentType);
- res.end(await metrics.register.metrics());
- } catch (ex) {
- req.log.error(ex);
- res.status(500).end();
- }
- });
+ app.get('/metrics', metrics.requestHandler);
/**
* @param {string[]} channels
@@ -443,7 +428,7 @@ const startServer = async () => {
* @param {string} message
*/
const onRedisMessage = (channel, message) => {
- redisMessagesReceived.inc();
+ metrics.redisMessagesReceived.inc();
const callbacks = subs[channel];
@@ -481,7 +466,7 @@ const startServer = async () => {
if (err) {
logger.error(`Error subscribing to ${channel}`);
} else if (typeof count === 'number') {
- redisSubscriptions.set(count);
+ metrics.redisSubscriptions.set(count);
}
});
}
@@ -508,7 +493,7 @@ const startServer = async () => {
if (err) {
logger.error(`Error unsubscribing to ${channel}`);
} else if (typeof count === 'number') {
- redisSubscriptions.set(count);
+ metrics.redisSubscriptions.set(count);
}
});
delete subs[channel];
@@ -688,13 +673,13 @@ const startServer = async () => {
unsubscribe(`${redisPrefix}${accessTokenChannelId}`, listener);
unsubscribe(`${redisPrefix}${systemChannelId}`, listener);
- connectedChannels.labels({ type: 'eventsource', channel: 'system' }).dec(2);
+ metrics.connectedChannels.labels({ type: 'eventsource', channel: 'system' }).dec(2);
});
subscribe(`${redisPrefix}${accessTokenChannelId}`, listener);
subscribe(`${redisPrefix}${systemChannelId}`, listener);
- connectedChannels.labels({ type: 'eventsource', channel: 'system' }).inc(2);
+ metrics.connectedChannels.labels({ type: 'eventsource', channel: 'system' }).inc(2);
};
/**
@@ -790,7 +775,7 @@ const startServer = async () => {
// TODO: Replace "string"-based delete payloads with object payloads:
const encodedPayload = typeof payload === 'object' ? JSON.stringify(payload) : payload;
- messagesSent.labels({ type: destinationType }).inc(1);
+ metrics.messagesSent.labels({ type: destinationType }).inc(1);
log.debug({ event, payload }, `Transmitting ${event} to ${req.accountId}`);
@@ -1027,11 +1012,11 @@ const startServer = async () => {
const streamToHttp = (req, res) => {
const channelName = channelNameFromPath(req);
- connectedClients.labels({ type: 'eventsource' }).inc();
+ metrics.connectedClients.labels({ type: 'eventsource' }).inc();
// In theory we'll always have a channel name, but channelNameFromPath can return undefined:
if (typeof channelName === 'string') {
- connectedChannels.labels({ type: 'eventsource', channel: channelName }).inc();
+ metrics.connectedChannels.labels({ type: 'eventsource', channel: channelName }).inc();
}
res.setHeader('Content-Type', 'text/event-stream');
@@ -1047,10 +1032,10 @@ const startServer = async () => {
// We decrement these counters here instead of in streamHttpEnd as in that
// method we don't have knowledge of the channel names
- connectedClients.labels({ type: 'eventsource' }).dec();
+ metrics.connectedClients.labels({ type: 'eventsource' }).dec();
// In theory we'll always have a channel name, but channelNameFromPath can return undefined:
if (typeof channelName === 'string') {
- connectedChannels.labels({ type: 'eventsource', channel: channelName }).dec();
+ metrics.connectedChannels.labels({ type: 'eventsource', channel: channelName }).dec();
}
clearInterval(heartbeat);
@@ -1324,7 +1309,7 @@ const startServer = async () => {
const stopHeartbeat = subscriptionHeartbeat(channelIds);
const listener = streamFrom(channelIds, request, logger, onSend, undefined, 'websocket', options.needsFiltering);
- connectedChannels.labels({ type: 'websocket', channel: channelName }).inc();
+ metrics.connectedChannels.labels({ type: 'websocket', channel: channelName }).inc();
subscriptions[channelIds.join(';')] = {
channelName,
@@ -1363,7 +1348,7 @@ const startServer = async () => {
unsubscribe(`${redisPrefix}${channelId}`, subscription.listener);
});
- connectedChannels.labels({ type: 'websocket', channel: subscription.channelName }).dec();
+ metrics.connectedChannels.labels({ type: 'websocket', channel: subscription.channelName }).dec();
subscription.stopHeartbeat();
delete subscriptions[channelIds.join(';')];
@@ -1421,7 +1406,7 @@ const startServer = async () => {
},
};
- connectedChannels.labels({ type: 'websocket', channel: 'system' }).inc(2);
+ metrics.connectedChannels.labels({ type: 'websocket', channel: 'system' }).inc(2);
};
/**
@@ -1433,7 +1418,7 @@ const startServer = async () => {
// Note: url.parse could throw, which would terminate the connection, so we
// increment the connected clients metric straight away when we establish
// the connection, without waiting:
- connectedClients.labels({ type: 'websocket' }).inc();
+ metrics.connectedClients.labels({ type: 'websocket' }).inc();
// Setup connection keep-alive state:
ws.isAlive = true;
@@ -1459,7 +1444,7 @@ const startServer = async () => {
});
// Decrement the metrics for connected clients:
- connectedClients.labels({ type: 'websocket' }).dec();
+ metrics.connectedClients.labels({ type: 'websocket' }).dec();
// We need to unassign the session object as to ensure it correctly gets
// garbage collected, without doing this we could accidentally hold on to
diff --git a/streaming/metrics.js b/streaming/metrics.js
index a029d778f..bb6bce3f3 100644
--- a/streaming/metrics.js
+++ b/streaming/metrics.js
@@ -4,12 +4,12 @@ import metrics from 'prom-client';
/**
* @typedef StreamingMetrics
- * @property {metrics.Registry} register
* @property {metrics.Gauge<"type">} connectedClients
* @property {metrics.Gauge<"type" | "channel">} connectedChannels
* @property {metrics.Gauge} redisSubscriptions
* @property {metrics.Counter} redisMessagesReceived
* @property {metrics.Counter<"type">} messagesSent
+ * @property {import('express').RequestHandler<{}>} requestHandler
*/
/**
@@ -92,8 +92,21 @@ export function setupMetrics(channels, pgPool) {
messagesSent.inc({ type: 'websocket' }, 0);
messagesSent.inc({ type: 'eventsource' }, 0);
+ /**
+ * @type {import('express').RequestHandler<{}>}
+ */
+ const requestHandler = (req, res) => {
+ metrics.register.metrics().then((output) => {
+ res.set('Content-Type', metrics.register.contentType);
+ res.end(output);
+ }).catch((err) => {
+ req.log.error(err, "Error collecting metrics");
+ res.status(500).end();
+ });
+ };
+
return {
- register: metrics.register,
+ requestHandler,
connectedClients,
connectedChannels,
redisSubscriptions,