Issue #115 - Write the current document id to disk

The idea is the metrics application can read this and know where
to point to, since the id will be changing week over week.

.gitignore

@@ -2,4 +2,5 @@ node_modules
 data
 config.json
 credentials.json
+currentDoc.json
 .vscode/

helpers.js

@@ -1,5 +1,6 @@
 const config = require('./config.json');
 const fetch = require('node-fetch');
+const fs = require('fs').promises;
 const retry = require('promise-fn-retry');
 const util = require('util');
 
@@ -213,6 +214,16 @@ function getQueryDates(inputDate) {
     return queryDates;
 }
 
+/**
+ * Write the passed in currentDocId to disk, so it can be read from other
+ * consumers.
+ * @param {string} currentDocId
+ */
+async function recordCurrentDoc(currentDocId) {
+    return fs.writeFile("currentDoc.json",
+        JSON.stringify({"currentDoc": currentDocId}), 'utf8');
+}
+
 /**
  * Return the list of query dates until the present, starting
  * at the specified date.
@@ -249,5 +260,6 @@ module.exports = {
     isMobile,
     isDesktop,
     isNotQA,
+    recordCurrentDoc,
     resumeQueryDates,
 }

index.js

@@ -66,8 +66,10 @@ const main = async () => {
 
         for (const writer of writers) {
             await spreadsheet.shareSheet(drive, currentDocId, writer);
-            console.log(`Current document ► https://docs.google.com/spreadsheets/d/${currentDocId}/edit`);
         }
+
+        console.log(`Current document ► https://docs.google.com/spreadsheets/d/${currentDocId}/edit`);
+        await helpers.recordCurrentDoc(currentDocId);
     }
 }