chore: refactor config class to a singleton (#6803)

This allows to pick up runtime configuration changes in the future
as well as allowing to simplify the code in future PRs. One possible
change is to remove `configure` and to move the remote configuration
to just update the singleton instead.

We can add events to activate and deactivate features as soon as
updates are incoming that are not handled by a simple property access.

That way most configurations will be changeable at runtime as soon
as the remote configuration handles all entries.

Drive by fix:

* test: fix test agent unsubscribe method

It is now going to remove the proper handler when being called.
Before, it could never match the handler due to not iterating
through the existing ones. It just tried to match for the method
which would always fail.

Author: BridgeAR

benchmark/core.js

@@ -3,7 +3,7 @@
 const benchmark = require('./benchmark')
 const proxyquire = require('proxyquire')
 
-const Config = require('../packages/dd-trace/src/config')
+const getConfig = require('../packages/dd-trace/src/config')
 const DatadogTracer = require('../packages/dd-trace/src/tracer')
 const DatadogSpanContext = require('../packages/dd-trace/src/opentracing/span_context')
 const TextMapPropagator = require('../packages/dd-trace/src/opentracing/propagation/text_map')
@@ -22,7 +22,7 @@ const Sampler = require('../packages/dd-trace/src/sampler')
 const format = require('../packages/dd-trace/src/format')
 const { AgentEncoder: Agent04Encoder } = require('../packages/dd-trace/src/encode/0.4')
 const { AgentEncoder: Agent05Encoder } = require('../packages/dd-trace/src/encode/0.5')
-const config = new Config({ service: 'benchmark' })
+const config = getConfig({ service: 'benchmark' })
 const id = require('../packages/dd-trace/src/id')
 const Histogram = require('../packages/dd-trace/src/histogram')
 const histogram = new Histogram()

benchmark/openfeature.js

@@ -4,12 +4,12 @@ const benchmark = require('./benchmark')
 const proxyquire = require('proxyquire')
 const { createSingleExposureEvent, createExposureEventArray } = require('./stubs/exposure-events')
 
-const Config = require('../packages/dd-trace/src/config')
+const getConfig = require('../packages/dd-trace/src/config')
 const ExposuresWriter = proxyquire('../packages/dd-trace/src/openfeature/writers/exposures', {
   '../../exporters/common/request': () => {}
 })
 
-const config = new Config({ service: 'benchmark', version: '1.0.0', env: 'test' })
+const config = getConfig({ service: 'benchmark', version: '1.0.0', env: 'test' })
 const suite = benchmark('openfeature')
 
 let writer

benchmark/sirun/debugger/start-devtools-client.js

@@ -1,14 +1,14 @@
 'use strict'
 
-const Config = require('../../../packages/dd-trace/src/config')
+const getConfig = require('../../../packages/dd-trace/src/config')
 const { start } = require('../../../packages/dd-trace/src/debugger')
 const { generateProbeConfig } = require('../../../packages/dd-trace/test/debugger/devtools_client/utils')
 
 const breakpoint = {
   file: process.env.BREAKPOINT_FILE,
   line: process.env.BREAKPOINT_LINE
 }
-const config = new Config()
+const config = getConfig()
 const rc = {
   setProductHandler (product, cb) {
     const action = 'apply'

packages/datadog-plugin-http/test/server.spec.js

@@ -17,6 +17,7 @@ describe('Plugin', () => {
   let tracer
   let port
   let app
+  let timeout
 
   ['http', 'node:http'].forEach(pluginToBeLoaded => {
     describe(`${pluginToBeLoaded}/server`, () => {
@@ -32,13 +33,15 @@ describe('Plugin', () => {
       afterEach(() => {
         appListener && appListener.close()
         app = null
+        clearTimeout(timeout)
+        timeout = null
         return agent.close({ ritmReset: false })
       })
 
       describe('canceled request', () => {
         beforeEach(() => {
           listener = (req, res) => {
-            setTimeout(() => {
+            timeout = setTimeout(() => {
               app && app(req, res)
               res.writeHead(200)
               res.end()

packages/datadog-plugin-openai/test/services.spec.js

@@ -1,6 +1,7 @@
 'use strict'
 
 const services = require('../src/services')
+const { getConfigFresh } = require('../../dd-trace/test/helpers/config')
 
 describe('Plugin', () => {
   describe('openai services', () => {
@@ -10,23 +11,23 @@ describe('Plugin', () => {
       })
 
       it('dogstatsd does not throw when missing .dogstatsd', () => {
-        const service = services.init({
+        const service = services.init(getConfigFresh({
           hostname: 'foo',
           service: 'bar',
           apiKey: 'my api key',
           interval: 1000
-        })
+        }))
 
         service.metrics.increment('mykey')
         service.logger.log('hello')
       })
 
       it('logger does not throw', () => {
-        const service = services.init({
+        const service = services.init(getConfigFresh({
           hostname: 'foo',
           service: 'bar',
           interval: 1000
-        })
+        }))
 
         service.logger.log('hello')
       })

packages/dd-trace/src/config.js

@@ -4,6 +4,7 @@ const fs = require('fs')
 const os = require('os')
 const uuid = require('crypto-randomuuid') // we need to keep the old uuid dep because of cypress
 const { URL } = require('url')
+
 const log = require('./log')
 const tagger = require('./tagger')
 const set = require('../../datadog-core/src/utils/src/set')
@@ -1507,4 +1508,12 @@ function getAgentUrl (url, options) {
   }
 }
 
-module.exports = Config
+let configInstance = null
+function getConfig (options) {
+  if (!configInstance) {
+    configInstance = new Config(options)
+  }
+  return configInstance
+}
+
+module.exports = getConfig

packages/dd-trace/src/proxy.js

@@ -1,7 +1,7 @@
 'use strict'
 const NoopProxy = require('./noop/proxy')
 const DatadogTracer = require('./tracer')
-const Config = require('./config')
+const getConfig = require('./config')
 const runtimeMetrics = require('./runtime_metrics')
 const log = require('./log')
 const { setStartupLogPluginManager } = require('./startup-log')
@@ -98,7 +98,7 @@ class Tracer extends NoopProxy {
     this._initialized = true
 
     try {
-      const config = new Config(options) // TODO: support dynamic code config
+      const config = getConfig(options) // TODO: support dynamic code config
 
       if (config.crashtracking.enabled) {
         require('./crashtracking').start(config)

packages/dd-trace/test/appsec/attacker-fingerprinting.express.plugin.spec.js

@@ -1,12 +1,13 @@
 'use strict'
 
+const path = require('node:path')
+
 const axios = require('axios')
 const { assert } = require('chai')
-const path = require('path')
 
 const agent = require('../plugins/agent')
 const appsec = require('../../src/appsec')
-const Config = require('../../src/config')
+const { getConfigFresh } = require('../helpers/config')
 const { withVersions } = require('../../../dd-trace/test/setup/mocha')
 
 withVersions('express', 'express', expressVersion => {
@@ -40,7 +41,7 @@ withVersions('express', 'express', expressVersion => {
     })
 
     beforeEach(() => {
-      appsec.enable(new Config(
+      appsec.enable(getConfigFresh(
         {
           appsec: {
             enabled: true,

packages/dd-trace/test/appsec/attacker-fingerprinting.fastify.plugin.spec.js

@@ -1,12 +1,13 @@
 'use strict'
 
+const path = require('node:path')
+
 const Axios = require('axios')
 const { assert } = require('chai')
-const path = require('path')
 
 const agent = require('../plugins/agent')
 const appsec = require('../../src/appsec')
-const Config = require('../../src/config')
+const { getConfigFresh } = require('../helpers/config')
 const { withVersions } = require('../setup/mocha')
 
 withVersions('fastify', 'fastify', fastifyVersion => {
@@ -40,7 +41,7 @@ withVersions('fastify', 'fastify', fastifyVersion => {
     })
 
     beforeEach(() => {
-      appsec.enable(new Config(
+      appsec.enable(getConfigFresh(
         {
           appsec: {
             enabled: true,

packages/dd-trace/test/appsec/attacker-fingerprinting.passport-http.plugin.spec.js

@@ -5,7 +5,7 @@ const { assert } = require('chai')
 
 const agent = require('../plugins/agent')
 const appsec = require('../../src/appsec')
-const Config = require('../../src/config')
+const { getConfigFresh } = require('../helpers/config')
 const { withVersions } = require('../setup/mocha')
 
 function assertFingerprintInTraces (traces) {
@@ -27,7 +27,7 @@ withVersions('passport-http', 'passport-http', version => {
     })
 
     before(() => {
-      appsec.enable(new Config({
+      appsec.enable(getConfigFresh({
         appsec: true
       }))
     })