Review update

CHANGELOG.md

@@ -9,7 +9,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ### Added
 
-- Optional `enableMetricsServer` option to enable of disable the metrics server.
+- Optional `enableMetricsServer` option to enable or disable the metrics server.
 - Exposed `getMetrics` function to get the metrics in prometheus exposition format.
 - Add support to instrument applications based on `Next.js` framework in Node.js environment.
 

src/OpenAPM.ts

@@ -34,6 +34,10 @@ export type DefaultLabels =
   | 'host';
 
 export interface OpenAPMOptions {
+  /**
+   * Enable the OpenAPM
+   */
+  enabled?: boolean;
   /**
    * Enable the metrics server
    * @default true
@@ -84,12 +88,13 @@ export class OpenAPM extends LevitateEvents {
   private simpleCache: Record<string, any> = {};
   private path: string;
   private metricsServerPort: number;
+  private enabled: boolean;
   private enableMetricsServer: boolean;
   readonly environment: string;
   readonly program: string;
   private defaultLabels?: Record<string, string>;
-  private requestsCounterConfig: CounterConfiguration<string>;
-  private requestDurationHistogramConfig: HistogramConfiguration<string>;
+  readonly requestsCounterConfig: CounterConfiguration<string>;
+  readonly requestDurationHistogramConfig: HistogramConfiguration<string>;
   private requestsCounter?: Counter;
   private requestsDurationHistogram?: Histogram;
   private extractLabels?: Record<string, ExtractFromParams>;
@@ -101,6 +106,7 @@ export class OpenAPM extends LevitateEvents {
   constructor(options?: OpenAPMOptions) {
     super(options);
     // Initializing all the options
+    this.enabled = options?.enabled ?? true;
     this.path = options?.path ?? '/metrics';
     this.metricsServerPort = options?.metricsServerPort ?? 9097;
     this.enableMetricsServer = options?.enableMetricsServer ?? true;
@@ -134,8 +140,10 @@ export class OpenAPM extends LevitateEvents {
     this.customPathsToMask = options?.customPathsToMask;
     this.excludeDefaultLabels = options?.excludeDefaultLabels;
 
-    this.initiateMetricsRoute();
-    this.initiatePromClient();
+    if (this.enabled) {
+      this.initiateMetricsRoute();
+      this.initiatePromClient();
+    }
   }
 
   private getDefaultLabels = () => {
@@ -174,6 +182,9 @@ export class OpenAPM extends LevitateEvents {
 
   public shutdown = async () => {
     return new Promise((resolve, reject) => {
+      if (!this.enabled) {
+        resolve(undefined);
+      }
       if (this.enableMetricsServer) {
         console.log('Shutting down metrics server gracefully.');
       }
@@ -276,6 +287,9 @@ export class OpenAPM extends LevitateEvents {
       res: ServerResponse<IncomingMessage>,
       time: number
     ) => {
+      if (!this.enabled) {
+        return;
+      }
       const sanitizedPathname = getSanitizedPath(req.originalUrl ?? '/');
       // Extract labels from the request params
       const { pathname, labels: parsedLabelsFromPathname } =
@@ -290,11 +304,7 @@ export class OpenAPM extends LevitateEvents {
       }
 
       // Make sure you copy baseURL in case of nested routes.
-      const path = req.route
-        ? req.route?.path !== '*'
-          ? req.baseUrl + req.route?.path
-          : pathname
-        : pathname;
+      const path = req.route ? req.baseUrl + req.route?.path : pathname;
 
       const labels: Record<string, string> = {
         path,
@@ -353,6 +363,9 @@ export class OpenAPM extends LevitateEvents {
   };
 
   public instrument(moduleName: SupportedModules) {
+    if (!this.enabled) {
+      return;
+    }
     try {
       if (moduleName === 'express') {
         const express = require('express');
@@ -368,10 +381,14 @@ export class OpenAPM extends LevitateEvents {
       }
       if (moduleName === 'nextjs') {
         const nextServer = require('next/dist/server/next-server');
-        instrumentNextjs(nextServer.default, {
-          counter: this.requestsCounter,
-          histogram: this.requestsDurationHistogram
-        });
+        instrumentNextjs(
+          nextServer.default,
+          {
+            counter: this.requestsCounter,
+            histogram: this.requestsDurationHistogram
+          },
+          this
+        );
       }
     } catch (error) {
       if (Object.keys(moduleNames).includes(moduleName)) {

src/clients/nextjs.ts

@@ -1,11 +1,12 @@
 import type NextNodeServer from 'next/dist/server/next-server';
+import prom, { Counter, Histogram } from 'prom-client';
 import chokidar from 'chokidar';
-import type { Counter, Histogram } from 'prom-client';
 import { wrap } from '../shimmer';
 import { loadManifest } from 'next/dist/server/load-manifest';
 import { join } from 'path';
 import { getRouteRegex } from 'next/dist/shared/lib/router/utils/route-regex';
 import { getRouteMatcher } from 'next/dist/shared/lib/router/utils/route-matcher';
+import OpenAPM from '../OpenAPM';
 
 const DOT_NEXT = join(process.cwd(), '.next');
 
@@ -84,8 +85,8 @@ const wrappedHandler = (
   handler: ReturnType<NextNodeServer['getRequestHandler']>,
   ctx: {
     getParameterizedRoute: (route: string) => string;
-    counter: Counter;
-    histogram: Histogram;
+    counter?: Counter;
+    histogram?: Histogram;
   }
 ) => {
   return async function (
@@ -104,15 +105,15 @@ const wrappedHandler = (
     );
 
     ctx.counter
-      .labels(
+      ?.labels(
         parsedPath !== '' ? parsedPath : '/',
         req.method ?? 'GET',
         res.statusCode?.toString() ?? '500'
       )
       .inc();
 
     ctx.histogram
-      .labels(
+      ?.labels(
         parsedPath !== '' ? parsedPath : '/',
         req.method ?? 'GET',
         res.statusCode?.toString() ?? '500'
@@ -125,12 +126,20 @@ const wrappedHandler = (
 
 export const instrumentNextjs = (
   nextServer: typeof NextNodeServer,
-  { counter, histogram }: { counter?: Counter; histogram?: Histogram }
+  { counter, histogram }: { counter?: Counter; histogram?: Histogram },
+  openapm: OpenAPM
 ) => {
-  if (!counter || !histogram) {
-    throw new Error(
-      'counter and histogram are required. Make sure you are using openmetrics mode.'
-    );
+  const ctx = {
+    counter,
+    histogram
+  };
+
+  if (typeof ctx.counter === 'undefined') {
+    ctx.counter = new prom.Counter(openapm.requestsCounterConfig);
+  }
+
+  if (typeof ctx.histogram === 'undefined') {
+    ctx.histogram = new prom.Histogram(openapm.requestDurationHistogramConfig);
   }
 
   PATHS_CACHE.setValue();