Add response time to pubsub events (#1155)

lib/api/middlewares/pubsub-metrics.js

@@ -41,6 +41,12 @@ function getEventData (req, res) {
         attributes.event_group_id = eventGroupId;
     }
 
+    const responseTime = getResponseTime(res);
+
+    if (responseTime) {
+        attributes.response_time = responseTime.toString();
+    }
+
     return { event, attributes };
 }
 
@@ -52,4 +58,17 @@ function normalizedField (field) {
     return field.toString().trim().substr(0, MAX_LENGTH);
 }
 
+function getResponseTime (res) {
+    const profiler = res.get('X-Tiler-Profiler');
+    let stats;
+
+    try {
+        stats = JSON.parse(profiler);
+    } catch (e) {
+        return undefined;
+    }
+
+    return stats.total;
+}
+
 module.exports = pubSubMetrics;