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Hook up prometheus metrics
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@Half-Shot
Half-Shot committed Aug 10, 2021
1 parent 1d624d0 commit 4c8d104
Showing 1 changed file with 48 additions and 59 deletions.
107 changes: 48 additions & 59 deletions src/components/prometheusmetrics.ts
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Original file line number Diff line number Diff line change
Expand Up @@ -15,10 +15,11 @@ limitations under the License.

import PromClient, { Registry } from "prom-client";
import { AgeCounters } from "./agecounters";
import JsSdk from "matrix-js-sdk";
import { Request, Response } from "express";
import { Bridge } from "..";
import Logger from "./logging";
import { Appservice as BotSdkAppservice, FunctionCallContext, METRIC_MATRIX_CLIENT_FAILED_FUNCTION_CALL,
METRIC_MATRIX_CLIENT_FUNCTION_CALL, METRIC_MATRIX_CLIENT_SUCCESSFUL_FUNCTION_CALL } from "matrix-bot-sdk";
type CollectorFunction = () => Promise<void>|void;

export interface BridgeGaugesCounts {
Expand Down Expand Up @@ -119,67 +120,53 @@ export class PrometheusMetrics {
* matrix-js-sdk. In particular, a metric is added that counts the number of
* calls to client API endpoints made by the client library.
*/
public registerMatrixSdkMetrics() {
public registerMatrixSdkMetrics(appservice: BotSdkAppservice): void {
const callCounts = this.addCounter({
name: "matrix_api_calls",
help: "Count of the number of Matrix client API calls made",
labels: ["method"],
});

/*
* We'll now annotate a bunch of the methods in MatrixClient to keep counts
* of every time they're called. This seems to be neater than trying to
* intercept all HTTP requests and try to intuit what internal method was
* invoked based on the HTTP URL.
* It's kind of messy to do this because we have to maintain a list of
* client SDK method names, but the only other alternative is to hook the
* 'request' function and attempt to parse methods out by inspecting the
* underlying client API HTTP URLs, and that is even messier. So this is
* the lesser of two evils.
*/
// eslint-disable-next-line @typescript-eslint/no-explicit-any
const matrixClientPrototype = (JsSdk as any).MatrixClient.prototype;

const CLIENT_METHODS = [
"ban",
"createAlias",
"createRoom",
"getProfileInfo",
"getStateEvent",
"invite",
"joinRoom",
"kick",
"leave",
"register",
"roomState",
"sendEvent",
"sendReceipt",
"sendStateEvent",
"sendTyping",
"setAvatarUrl",
"setDisplayName",
"setPowerLevel",
"setPresence",
"setProfileInfo",
"unban",
"uploadContent",
];

CLIENT_METHODS.forEach(function(method) {
callCounts.inc({method: method}, 0); // initialise the count to zero

const orig = matrixClientPrototype[method];
matrixClientPrototype[method] = function(...args: unknown[]) {
callCounts.inc({method: method});
return orig.apply(this, args);
}
const callCountsFailed = this.addCounter({
name: "matrix_api_calls_failed",
help: "Count of the number of Matrix client API calls made",
labels: ["method"],
});

appservice.metrics.registerListener({
onStartMetric: () => {
// Not used yet.
},
onEndMetric: () => {
// Not used yet.
},
onIncrement: (metricName, context) => {
if (metricName === METRIC_MATRIX_CLIENT_SUCCESSFUL_FUNCTION_CALL) {
const ctx = context as FunctionCallContext;
callCounts.inc({method: ctx.functionName});
}
if (metricName === METRIC_MATRIX_CLIENT_FAILED_FUNCTION_CALL) {
const ctx = context as FunctionCallContext;
callCountsFailed.inc({method: ctx.functionName});
}
},
onDecrement: () => {
// Not used yet.
},
onReset: (metricName) => {
if (metricName === METRIC_MATRIX_CLIENT_SUCCESSFUL_FUNCTION_CALL) {
callCounts.reset();
}
if (metricName === METRIC_MATRIX_CLIENT_FAILED_FUNCTION_CALL) {
callCountsFailed.reset();
}
},
})
}

/**
* Fetch metrics from all configured collectors
*/
public async refresh () {
public async refresh (): Promise<void> {
try {
await Promise.all(this.collectors.map((f) => f()));
}
Expand All @@ -194,7 +181,8 @@ export class PrometheusMetrics {
* @param {BridgeGaugesCallback} counterFunc A function that when invoked
* returns the current counts of various items in the bridge.
*/
public async registerBridgeGauges (counterFunc: () => Promise<BridgeGaugesCounts>|BridgeGaugesCounts) {
public async registerBridgeGauges (
counterFunc: () => Promise<BridgeGaugesCounts>|BridgeGaugesCounts): Promise<void> {
const matrixRoomsGauge = this.addGauge({
name: "matrix_configured_rooms",
help: "Current count of configured rooms by matrix room ID",
Expand Down Expand Up @@ -262,7 +250,7 @@ export class PrometheusMetrics {
* This function is passed no arguments and is not expected to return anything.
* It runs purely to have a side-effect on previously registered gauges.
*/
public addCollector (func: CollectorFunction) {
public addCollector (func: CollectorFunction): void {
this.collectors.push(func);
}

Expand All @@ -281,7 +269,7 @@ export class PrometheusMetrics {
* gauge in order to provide a new value for it.
* @return {Gauge} A gauge metric.
*/
public addGauge (opts: GagueOpts) {
public addGauge (opts: GagueOpts): PromClient.Gauge<string> {
const refresh = opts.refresh;
const name = [opts.namespace || "bridge", opts.name].join("_");

Expand Down Expand Up @@ -311,7 +299,7 @@ export class PrometheusMetrics {
* @param {Array<string>=} opts.labels An optional list of string label names
* @return {Counter} A counter metric.
*/
public addCounter (opts: CounterOpts) {
public addCounter (opts: CounterOpts): PromClient.Counter<string> {
const name = [opts.namespace || "bridge", opts.name].join("_");

const counter = this.counters[opts.name] =
Expand All @@ -330,7 +318,7 @@ export class PrometheusMetrics {
* @param{string} name The name the metric was previously registered as.
* @param{Object} labels Optional object containing additional label values.
*/
public incCounter (name: string, labels: {[label: string]: string}) {
public incCounter (name: string, labels: {[label: string]: string}): void {
if (!this.counters[name]) {
throw new Error("Unrecognised counter metric name '" + name + "'");
}
Expand Down Expand Up @@ -360,7 +348,8 @@ export class PrometheusMetrics {
help: opts.help,
labelNames: opts.labels || [],
registers: [this.register],
buckets: opts.buckets,
// Only apply buckets if defined
...(opts.buckets !== undefined ? {buckets: opts.buckets} : undefined),
});
return timer;
}
Expand All @@ -372,7 +361,7 @@ export class PrometheusMetrics {
* @return {function} A function to be called to end the timer and report the
* observation.
*/
public startTimer(name: string, labels: {[label: string]: string}) {
public startTimer(name: string, labels: {[label: string]: string}): () => void {
if (!this.timers[name]) {
throw Error("Unrecognised timer metric name '" + name + "'");
}
Expand All @@ -385,7 +374,7 @@ export class PrometheusMetrics {
* containing Express app.
* @param {Bridge} bridge The containing Bridge instance.
*/
public addAppServicePath(bridge: Bridge) {
public addAppServicePath(bridge: Bridge): void {
bridge.addAppServicePath({
method: "GET",
path: "/metrics",
Expand Down

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