env var to disable all middleware spans

packages/datadog-plugin-express/test/integration-test/client.spec.js

@@ -36,6 +36,7 @@ describe('esm', () => {
     })
 
     it('is instrumented', async () => {
+      delete process.env.DD_TRACE_MIDDLEWARE_ENABLED
       proc = await spawnPluginIntegrationTestProc(sandbox.folder, 'server.mjs', agent.port)
       const numberOfSpans = semver.intersects(version, '<5.0.0') ? 4 : 3
 
@@ -49,5 +50,20 @@ describe('esm', () => {
         assert.propertyVal(payload[0][1], 'name', 'express.middleware')
       })
     }).timeout(50000)
+
+    it('disables middleware spans when config.middleware is set to false through environment variable', async () => {
+      process.env.DD_TRACE_MIDDLEWARE_ENABLED = false
+      proc = await spawnPluginIntegrationTestProc(sandbox.folder, 'server.mjs', agent.port)
+      const numberOfSpans = 1
+
+      return curlAndAssertMessage(agent, proc, ({ headers, payload }) => {
+        assert.propertyVal(headers, 'host', `127.0.0.1:${agent.port}`)
+        assert.isArray(payload)
+        assert.strictEqual(payload.length, 1)
+        assert.isArray(payload[0])
+        assert.strictEqual(payload[0].length, numberOfSpans)
+        assert.propertyVal(payload[0][0], 'name', 'express.request')
+      })
+    }).timeout(50000)
   })
 })

packages/datadog-plugin-web/src/index.js

@@ -9,7 +9,7 @@ class WebPlugin extends Plugin {
   }
 
   configure (config) {
-    return super.configure(web.normalizeConfig(config))
+    return super.configure(web.normalizeConfig(config, this._tracerConfig))
   }
 
   setFramework (req, name, config) {

packages/dd-trace/src/config.js

@@ -520,6 +520,7 @@ class Config {
     this._setValue(defaults, 'lookup', undefined)
     this._setValue(defaults, 'inferredProxyServicesEnabled', false)
     this._setValue(defaults, 'memcachedCommandEnabled', false)
+    this._setValue(defaults, 'middleware', true)
     this._setValue(defaults, 'openAiLogsEnabled', false)
     this._setValue(defaults, 'openaiSpanCharLimit', 128)
     this._setValue(defaults, 'peerServiceMapping', {})
@@ -670,6 +671,7 @@ class Config {
       DD_TRACE_HEADER_TAGS,
       DD_TRACE_LEGACY_BAGGAGE_ENABLED,
       DD_TRACE_MEMCACHED_COMMAND_ENABLED,
+      DD_TRACE_MIDDLEWARE_ENABLED,
       DD_TRACE_OBFUSCATION_QUERY_STRING_REGEXP,
       DD_TRACE_PARTIAL_FLUSH_MIN_SPANS,
       DD_TRACE_PEER_SERVICE_MAPPING,
@@ -801,6 +803,7 @@ class Config {
     this._setBoolean(env, 'logInjection', DD_LOGS_INJECTION)
     // Requires an accompanying DD_APM_OBFUSCATION_MEMCACHED_KEEP_COMMAND=true in the agent
     this._setBoolean(env, 'memcachedCommandEnabled', DD_TRACE_MEMCACHED_COMMAND_ENABLED)
+    this._setBoolean(env, 'middleware', DD_TRACE_MIDDLEWARE_ENABLED)
     this._setBoolean(env, 'openAiLogsEnabled', DD_OPENAI_LOGS_ENABLED)
     this._setValue(env, 'openaiSpanCharLimit', maybeInt(DD_OPENAI_SPAN_CHAR_LIMIT))
     this._envUnprocessed.openaiSpanCharLimit = DD_OPENAI_SPAN_CHAR_LIMIT
@@ -982,6 +985,7 @@ class Config {
     this._setString(opts, 'llmobs.mlApp', options.llmobs?.mlApp)
     this._setBoolean(opts, 'logInjection', options.logInjection)
     this._setString(opts, 'lookup', options.lookup)
+    this._setBoolean(opts, 'middleware', options.middleware)
     this._setBoolean(opts, 'openAiLogsEnabled', options.openAiLogsEnabled)
     this._setValue(opts, 'peerServiceMapping', options.peerServiceMapping)
     this._setBoolean(opts, 'plugins', options.plugins)

packages/dd-trace/src/plugins/util/web.js

@@ -40,12 +40,12 @@ const web = {
   TYPE: WEB,
 
   // Ensure the configuration has the correct structure and defaults.
-  normalizeConfig (config) {
+  normalizeConfig (config, tracerConfig) {
     const headers = getHeadersToRecord(config)
     const validateStatus = getStatusValidator(config)
     const hooks = getHooks(config)
     const filter = urlFilter.getFilter(config)
-    const middleware = getMiddlewareSetting(config)
+    const middleware = getMiddlewareSetting(config, tracerConfig)
     const queryStringObfuscation = getQsObfuscator(config)
 
     return {
@@ -570,11 +570,16 @@ function getHooks (config) {
   return { request }
 }
 
-function getMiddlewareSetting (config) {
-  if (config && typeof config.middleware === 'boolean') {
-    return config.middleware
-  } else if (config && config.hasOwnProperty('middleware')) {
-    log.error('Expected `middleware` to be a boolean.')
+function getMiddlewareSetting (config, tracerConfig) {
+  if (config) {
+    if (typeof config.middleware === 'boolean') {
+      return config.middleware
+    } else if (config.hasOwnProperty('middleware')) {
+      log.error('Expected `middleware` to be a boolean.')
+    }
+  }
+  if (tracerConfig && tracerConfig.middleware === false) {
+    return false
   }
 
   return true