Remove prometheus depenedency from backend-common

packages/backend-common/package.json

@@ -41,7 +41,6 @@
     "cors": "^2.8.5",
     "cross-fetch": "^3.0.6",
     "express": "^4.17.1",
-    "express-prom-bundle": "^6.1.0",
     "express-promise-router": "^3.0.3",
     "fs-extra": "^9.0.1",
     "git-url-parse": "^11.4.0",
@@ -51,7 +50,6 @@
     "logform": "^2.1.1",
     "minimist": "^1.2.5",
     "morgan": "^1.10.0",
-    "prom-client": "^12.0.0",
     "selfsigned": "^1.10.7",
     "stoppable": "^1.1.0",
     "tar": "^6.0.5",

packages/backend-common/src/service/lib/ServiceBuilderImpl.ts

@@ -39,7 +39,6 @@ import {
   readHttpsSettings,
 } from './config';
 import { createHttpServer, createHttpsServer } from './hostFactory';
-import { metricsHandler } from './metrics';
 
 export const DEFAULT_PORT = 7000;
 // '' is express default, which listens to all interfaces
@@ -66,7 +65,6 @@ export class ServiceBuilderImpl implements ServiceBuilder {
   private corsOptions: cors.CorsOptions | undefined;
   private cspOptions: Record<string, string[] | false> | undefined;
   private httpsSettings: HttpsSettings | undefined;
-  private enableMetrics: boolean = true;
   private routers: [string, Router][];
   // Reference to the module where builder is created - needed for hot module
   // reloading
@@ -109,9 +107,6 @@ export class ServiceBuilderImpl implements ServiceBuilder {
       this.httpsSettings = httpsSettings;
     }
 
-    // For now, configuration of metrics is a simple boolean and active by default
-    this.enableMetrics = backendConfig.getOptionalBoolean('metrics') !== false;
-
     return this;
   }
 
@@ -166,9 +161,6 @@ export class ServiceBuilderImpl implements ServiceBuilder {
       app.use(cors(corsOptions));
     }
     app.use(compression());
-    if (this.enableMetrics) {
-      app.use(metricsHandler());
-    }
     app.use(requestLoggingHandler());
     for (const [root, route] of this.routers) {
       app.use(root, route);

packages/backend-common/src/service/lib/metrics.test.ts

@@ -1,37 +0,0 @@
-/*
- * Copyright 2020 Spotify AB
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *     http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-
-import { normalizePath } from './metrics';
-
-describe('normalizePath', () => {
-  it('should normalize /path to /path', async () => {
-    const path = normalizePath({ url: 'http://server/path' });
-
-    expect(path).toBe('/path');
-  });
-
-  it('should normalize /path/test to /path', async () => {
-    const path = normalizePath({ url: 'http://server/path/test' });
-
-    expect(path).toBe('/path');
-  });
-
-  it('should normalize /api/plugin-name/test to /api/plugin-name', async () => {
-    const path = normalizePath({ url: 'http://server/api/plugin-name/test' });
-
-    expect(path).toBe('/api/plugin-name');
-  });
-});

packages/backend-common/src/service/lib/metrics.ts

@@ -1,53 +0,0 @@
-/*
- * Copyright 2020 Spotify AB
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *     http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-import prom from 'prom-client';
-import promBundle from 'express-prom-bundle';
-import { RequestHandler } from 'express';
-import * as url from 'url';
-
-const rootRegEx = new RegExp('^/([^/]*)/.*');
-const apiRegEx = new RegExp('^/api/([^/]*)/.*');
-
-export function normalizePath(req: any): string {
-  const path = url.parse(req.originalUrl || req.url).pathname || '/';
-
-  // Capture /api/ and the plugin name
-  if (apiRegEx.test(path)) {
-    return path.replace(apiRegEx, '/api/$1');
-  }
-
-  // Only the first path segment at root level
-  return path.replace(rootRegEx, '/$1');
-}
-
-/**
- * Adds a /metrics endpoint, register default runtime metrics and instrument the router.
- */
-export function metricsHandler(): RequestHandler {
-  // We can only initialize the metrics once and have to clean them up between hot reloads
-  prom.register.clear();
-
-  return promBundle({
-    includeMethod: true,
-    includePath: true,
-    // Using includePath alone is problematic, as it will include path labels with high
-    // cardinality (e.g. path params). Instead we would have to template them. However, this
-    // is difficult, as every backend plugin might use different routes. Instead we only take
-    // the first directory of the path, to have at least an idea how each plugin performs:
-    normalizePath,
-    promClient: { collectDefaultMetrics: {} },
-  });
-}