Use the same tags across connect-datadog and hot-shots (github#24741)

* use the same tags across connect-datadog and hot-shots

Author: mikesurowiec

lib/statsd.js

@@ -1,15 +1,16 @@
 import StatsD from 'hot-shots'
 
-const mock = Boolean(process.env.NODE_ENV === 'test' || !process.env.DD_API_KEY)
+const { HEROKU_APP_NAME, NODE_ENV, DD_API_KEY } = process.env
+const mock = Boolean(NODE_ENV === 'test' || !DD_API_KEY)
 
+export const tags = ['app:docs', HEROKU_APP_NAME ? `heroku_app:${HEROKU_APP_NAME}` : false].filter(
+  Boolean
+)
 /**
  * @type {import('hot-shots').StatsD}
  */
 export default new StatsD({
   prefix: 'docs.',
   mock,
-  globalTags: {
-    app: 'docs',
-    heroku_app: process.env.HEROKU_APP_NAME,
-  },
+  globalTags: tags,
 })

middleware/connect-datadog.js

@@ -1,13 +1,7 @@
 import connectDatadog from 'connect-datadog'
-import statsd from '../lib/statsd.js'
+import statsd, { tags } from '../lib/statsd.js'
 
 export default (req, res, next) => {
-  const tags = []
-
-  if ('nextjs' in req.query) {
-    tags.push('nextjs')
-  }
-
   return connectDatadog({
     dogstatsd: statsd,
     method: true, // Track HTTP methods (GET, POST, etc)