Be able to tag requests with labels as easier way to provide business metrics

lib/api/middlewares/tag.js

@@ -0,0 +1,15 @@
+'use strict';
+
+module.exports = function tag ({ tags }) {
+    if (!Array.isArray(tags) || !tags.every((tag) => typeof tag === 'string')) {
+        throw new Error('Required "tags" option must be a valid Array: [string, string, ...]');
+    }
+
+    return function tagMiddleware (req, res, next) {
+        const { logger } = res.locals;
+        res.locals.tags = tags;
+        res.on('finish', () => logger.info({ tags: res.locals.tags }));
+
+        next();
+    };
+};