Fix #1692, add GA logging for any shots that are deleted after the ex…

…piration time

docs/METRICS.md

@@ -202,6 +202,10 @@ These are events that an add-on user can encounter on a shot they own
 8. ~~Switch to clip view from full page (already covered)~~
 9. [x] Click on clip (already covered)
 
+#### Server events
+
+1. [x] When an expired shot is deleted (about 2 weeks after expiration) it sends `server/clean-deleted-shot` with an eventValue of the number of shots cleaned at that moment.  (By default these are checked every minute.)
+
 #### Homepage web visits
 
 1. ~~Click install from Firefox, `web/start-install/homepage-firefox`~~

server/src/jobs.js

@@ -2,21 +2,30 @@
 
 const config = require("./config").getProperties();
 const mozlog = require("mozlog")("jobs");
+const ua = require("universal-analytics");
 
 // Convert to milliseconds:
-let keepTime = config.exportKeepTime * 60 * 1000;
+//let keepTime = config.exportKeepTime * 60 * 1000;
 let checkDeletedInterval = config.checkDeletedInterval * 1000;
 
 exports.start = function () {
 
-  setInterval(require("./exporter").cleanExports, keepTime / 10);
+  //setInterval(require("./exporter").cleanExports, keepTime / 10);
 
   setInterval(function () {
     require("./servershot").Shot.cleanDeletedShots()
       .then((rowCount) => {
         if (rowCount) {
           mozlog.info("cleaning-expired-shots", {rowCount});
         }
+        if (config.gaId) {
+          let analytics = ua(config.gaId);
+          analytics.event({
+            ec: "server",
+            ea: "clean-deleted-shot",
+            ev: rowCount
+          }).send();
+        }
       })
       .catch((e) => {
         mozlog.error("error-cleaning-shots", {