(core) Add optional telemetry to grist-core

Summary:
Adds support for optional telemetry to grist-core.

A new environment variable, GRIST_TELEMETRY_LEVEL, controls the level of telemetry collected.

Test Plan: Server and unit tests.

Reviewers: paulfitz

Reviewed By: paulfitz

Subscribers: dsagal, anaisconce

Differential Revision: https://phab.getgrist.com/D3880

app/client/lib/helpScout.ts

@@ -197,11 +197,11 @@ function _beaconOpen(userObj: IUserObj|null, options: IBeaconOpenOptions) {
 
   Beacon('once', 'open', () => logTelemetryEvent('beaconOpen'));
   Beacon('on', 'article-viewed', (article) => logTelemetryEvent('beaconArticleViewed', {
-    articleId: article!.id,
+    full: {articleId: article!.id},
   }));
   Beacon('on', 'email-sent', () => logTelemetryEvent('beaconEmailSent'));
   Beacon('on', 'search', (search) => logTelemetryEvent('beaconSearch', {
-    searchQuery: search!.query,
+    full: {searchQuery: search!.query},
   }));
 }
 

app/client/lib/telemetry.ts

@@ -1,14 +1,20 @@
 import {logError} from 'app/client/models/errors';
-import {TelemetryEventName} from 'app/common/Telemetry';
-import {fetchFromHome, pageHasHome} from 'app/common/urlUtils';
+import {Level, TelemetryContracts, TelemetryEvent, TelemetryMetadataByLevel} from 'app/common/Telemetry';
+import {fetchFromHome, getGristConfig, pageHasHome} from 'app/common/urlUtils';
 
-export function logTelemetryEvent(name: TelemetryEventName, metadata?: Record<string, any>) {
+export function logTelemetryEvent(event: TelemetryEvent, metadata?: TelemetryMetadataByLevel) {
   if (!pageHasHome()) { return; }
 
+  const {telemetry} = getGristConfig();
+  if (!telemetry) { return; }
+
+  const {telemetryLevel} = telemetry;
+  if (Level[telemetryLevel] < TelemetryContracts[event].minimumTelemetryLevel) { return; }
+
   fetchFromHome('/api/telemetry', {
     method: 'POST',
     body: JSON.stringify({
-      name,
+      event,
       metadata,
     }),
     credentials: 'include',
@@ -17,7 +23,7 @@ export function logTelemetryEvent(name: TelemetryEventName, metadata?: Record<st
       'X-Requested-With': 'XMLHttpRequest',
     },
   }).catch((e: Error) => {
-    console.warn(`Failed to log telemetry event ${name}`, e);
+    console.warn(`Failed to log telemetry event ${event}`, e);
     logError(e);
   });
 }