diff --git a/streaming/index.js b/streaming/index.js
index e3b63b53a..fb3e3fb2b 100644
--- a/streaming/index.js
+++ b/streaming/index.js
@@ -12,10 +12,12 @@ const { JSDOM } = require('jsdom');
const log = require('npmlog');
const pg = require('pg');
const dbUrlToConfig = require('pg-connection-string').parse;
-const metrics = require('prom-client');
const uuid = require('uuid');
const WebSocket = require('ws');
+const { setupMetrics } = require('./metrics');
+const { isTruthy } = require("./utils");
+
const environment = process.env.NODE_ENV || 'development';
// Correctly detect and load .env or .env.production file based on environment:
@@ -196,78 +198,15 @@ const startServer = async () => {
const redisClient = await createRedisClient(redisConfig);
const { redisPrefix } = redisConfig;
- // Collect metrics from Node.js
- metrics.collectDefaultMetrics();
-
- new metrics.Gauge({
- name: 'pg_pool_total_connections',
- help: 'The total number of clients existing within the pool',
- collect() {
- this.set(pgPool.totalCount);
- },
- });
-
- new metrics.Gauge({
- name: 'pg_pool_idle_connections',
- help: 'The number of clients which are not checked out but are currently idle in the pool',
- collect() {
- this.set(pgPool.idleCount);
- },
- });
-
- new metrics.Gauge({
- name: 'pg_pool_waiting_queries',
- help: 'The number of queued requests waiting on a client when all clients are checked out',
- collect() {
- this.set(pgPool.waitingCount);
- },
- });
-
- const connectedClients = new metrics.Gauge({
- name: 'connected_clients',
- help: 'The number of clients connected to the streaming server',
- labelNames: ['type'],
- });
-
- const connectedChannels = new metrics.Gauge({
- name: 'connected_channels',
- help: 'The number of channels the streaming server is streaming to',
- labelNames: [ 'type', 'channel' ]
- });
-
- const redisSubscriptions = new metrics.Gauge({
- name: 'redis_subscriptions',
- help: 'The number of Redis channels the streaming server is subscribed to',
- });
-
- const redisMessagesReceived = new metrics.Counter({
- name: 'redis_messages_received_total',
- help: 'The total number of messages the streaming server has received from redis subscriptions'
- });
-
- const messagesSent = new metrics.Counter({
- name: 'messages_sent_total',
- help: 'The total number of messages the streaming server sent to clients per connection type',
- labelNames: [ 'type' ]
- });
-
- // Prime the gauges so we don't loose metrics between restarts:
- redisSubscriptions.set(0);
- connectedClients.set({ type: 'websocket' }, 0);
- connectedClients.set({ type: 'eventsource' }, 0);
-
- // For each channel, initialize the gauges at zero; There's only a finite set of channels available
- CHANNEL_NAMES.forEach(( channel ) => {
- connectedChannels.set({ type: 'websocket', channel }, 0);
- connectedChannels.set({ type: 'eventsource', channel }, 0);
- });
-
- // Prime the counters so that we don't loose metrics between restarts.
- // Unfortunately counters don't support the set() API, so instead I'm using
- // inc(0) to achieve the same result.
- redisMessagesReceived.inc(0);
- messagesSent.inc({ type: 'websocket' }, 0);
- messagesSent.inc({ type: 'eventsource' }, 0);
+ 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
@@ -388,25 +327,6 @@ const startServer = async () => {
}
};
- const FALSE_VALUES = [
- false,
- 0,
- '0',
- 'f',
- 'F',
- 'false',
- 'FALSE',
- 'off',
- 'OFF',
- ];
-
- /**
- * @param {any} value
- * @returns {boolean}
- */
- const isTruthy = value =>
- value && !FALSE_VALUES.includes(value);
-
/**
* @param {any} req
* @param {any} res
diff --git a/streaming/metrics.js b/streaming/metrics.js
new file mode 100644
index 000000000..d05b4c9b1
--- /dev/null
+++ b/streaming/metrics.js
@@ -0,0 +1,105 @@
+// @ts-check
+
+const metrics = require('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
+ */
+
+/**
+ *
+ * @param {string[]} channels
+ * @param {import('pg').Pool} pgPool
+ * @returns {StreamingMetrics}
+ */
+function setupMetrics(channels, pgPool) {
+ // Collect metrics from Node.js
+ metrics.collectDefaultMetrics();
+
+ new metrics.Gauge({
+ name: 'pg_pool_total_connections',
+ help: 'The total number of clients existing within the pool',
+ collect() {
+ this.set(pgPool.totalCount);
+ },
+ });
+
+ new metrics.Gauge({
+ name: 'pg_pool_idle_connections',
+ help: 'The number of clients which are not checked out but are currently idle in the pool',
+ collect() {
+ this.set(pgPool.idleCount);
+ },
+ });
+
+ new metrics.Gauge({
+ name: 'pg_pool_waiting_queries',
+ help: 'The number of queued requests waiting on a client when all clients are checked out',
+ collect() {
+ this.set(pgPool.waitingCount);
+ },
+ });
+
+ const connectedClients = new metrics.Gauge({
+ name: 'connected_clients',
+ help: 'The number of clients connected to the streaming server',
+ labelNames: ['type'],
+ });
+
+ const connectedChannels = new metrics.Gauge({
+ name: 'connected_channels',
+ help: 'The number of channels the streaming server is streaming to',
+ labelNames: [ 'type', 'channel' ]
+ });
+
+ const redisSubscriptions = new metrics.Gauge({
+ name: 'redis_subscriptions',
+ help: 'The number of Redis channels the streaming server is subscribed to',
+ });
+
+ const redisMessagesReceived = new metrics.Counter({
+ name: 'redis_messages_received_total',
+ help: 'The total number of messages the streaming server has received from redis subscriptions'
+ });
+
+ const messagesSent = new metrics.Counter({
+ name: 'messages_sent_total',
+ help: 'The total number of messages the streaming server sent to clients per connection type',
+ labelNames: [ 'type' ]
+ });
+
+ // Prime the gauges so we don't loose metrics between restarts:
+ redisSubscriptions.set(0);
+ connectedClients.set({ type: 'websocket' }, 0);
+ connectedClients.set({ type: 'eventsource' }, 0);
+
+ // For each channel, initialize the gauges at zero; There's only a finite set of channels available
+ channels.forEach(( channel ) => {
+ connectedChannels.set({ type: 'websocket', channel }, 0);
+ connectedChannels.set({ type: 'eventsource', channel }, 0);
+ });
+
+ // Prime the counters so that we don't loose metrics between restarts.
+ // Unfortunately counters don't support the set() API, so instead I'm using
+ // inc(0) to achieve the same result.
+ redisMessagesReceived.inc(0);
+ messagesSent.inc({ type: 'websocket' }, 0);
+ messagesSent.inc({ type: 'eventsource' }, 0);
+
+ return {
+ register: metrics.register,
+ connectedClients,
+ connectedChannels,
+ redisSubscriptions,
+ redisMessagesReceived,
+ messagesSent,
+ };
+}
+
+exports.setupMetrics = setupMetrics;
diff --git a/streaming/utils.js b/streaming/utils.js
new file mode 100644
index 000000000..ad8dd4889
--- /dev/null
+++ b/streaming/utils.js
@@ -0,0 +1,22 @@
+// @ts-check
+
+const FALSE_VALUES = [
+ false,
+ 0,
+ '0',
+ 'f',
+ 'F',
+ 'false',
+ 'FALSE',
+ 'off',
+ 'OFF',
+];
+
+/**
+ * @param {any} value
+ * @returns {boolean}
+ */
+const isTruthy = value =>
+ value && !FALSE_VALUES.includes(value);
+
+exports.isTruthy = isTruthy;