fix(analytics-process): fix retrieving events from storage

CHANGELOG.md

@@ -1,3 +1,7 @@
+## [1.3.1] - 2020-12-20
+
+- Fixes a bug that caused the stored in memory events when in batch mode to be overwriten by the first events sent, thus being lost. To avoid a breaking change, the temporal solution was to move the process that pulls from memory old stored not sent events from the batch timer process, to happen when the user sends events for the first time. The problem this solution brings is that we need the caller to push new events in order to get the old stored events to be pushed. If the first thing don't happen the second won't either. But this is better than the previous scenario of lost events. For further details you can check [this PR](https://github.com/koa-health/mixpanel_analytics/pull/9)
+
 ## [1.3.0] - 2020-08-19
 
 - Added `useIp` property.

example/pubspec.lock

@@ -1,69 +1,62 @@
 # Generated by pub
 # See https://dart.dev/tools/pub/glossary#lockfile
 packages:
-  archive:
-    dependency: transitive
-    description:
-      name: archive
-      url: "https://pub.dartlang.org"
-    source: hosted
-    version: "2.0.13"
-  args:
-    dependency: transitive
-    description:
-      name: args
-      url: "https://pub.dartlang.org"
-    source: hosted
-    version: "1.6.0"
   async:
     dependency: transitive
     description:
       name: async
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "2.4.1"
+    version: "2.5.0-nullsafety.1"
   boolean_selector:
     dependency: transitive
     description:
       name: boolean_selector
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "2.0.0"
-  charcode:
+    version: "2.1.0-nullsafety.1"
+  characters:
     dependency: transitive
     description:
-      name: charcode
+      name: characters
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "1.1.3"
-  collection:
+    version: "1.1.0-nullsafety.3"
+  charcode:
     dependency: transitive
     description:
-      name: collection
+      name: charcode
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "1.14.12"
-  convert:
+    version: "1.2.0-nullsafety.1"
+  clock:
     dependency: transitive
     description:
-      name: convert
+      name: clock
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "2.1.1"
-  crypto:
+    version: "1.1.0-nullsafety.1"
+  collection:
     dependency: transitive
     description:
-      name: crypto
+      name: collection
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "2.1.4"
+    version: "1.15.0-nullsafety.3"
   cupertino_icons:
     dependency: "direct main"
     description:
       name: cupertino_icons
       url: "https://pub.dartlang.org"
     source: hosted
     version: "0.1.2"
+  fake_async:
+    dependency: transitive
+    description:
+      name: fake_async
+      url: "https://pub.dartlang.org"
+    source: hosted
+    version: "1.2.0-nullsafety.1"
   flutter:
     dependency: "direct main"
     description: flutter
@@ -88,62 +81,41 @@ packages:
       url: "https://pub.dartlang.org"
     source: hosted
     version: "3.1.3"
-  image:
-    dependency: transitive
-    description:
-      name: image
-      url: "https://pub.dartlang.org"
-    source: hosted
-    version: "2.1.12"
   matcher:
     dependency: transitive
     description:
       name: matcher
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "0.12.6"
+    version: "0.12.10-nullsafety.1"
   meta:
     dependency: transitive
     description:
       name: meta
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "1.1.8"
+    version: "1.3.0-nullsafety.3"
   mixpanel_analytics:
     dependency: "direct main"
     description:
       path: ".."
       relative: true
     source: path
-    version: "1.2.1"
+    version: "1.3.1"
   path:
     dependency: transitive
     description:
       name: path
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "1.6.4"
+    version: "1.8.0-nullsafety.1"
   pedantic:
     dependency: transitive
     description:
       name: pedantic
       url: "https://pub.dartlang.org"
     source: hosted
     version: "1.8.0+1"
-  petitparser:
-    dependency: transitive
-    description:
-      name: petitparser
-      url: "https://pub.dartlang.org"
-    source: hosted
-    version: "2.4.0"
-  quiver:
-    dependency: transitive
-    description:
-      name: quiver
-      url: "https://pub.dartlang.org"
-    source: hosted
-    version: "2.1.3"
   shared_preferences:
     dependency: transitive
     description:
@@ -162,63 +134,56 @@ packages:
       name: source_span
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "1.7.0"
+    version: "1.8.0-nullsafety.2"
   stack_trace:
     dependency: transitive
     description:
       name: stack_trace
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "1.9.3"
+    version: "1.10.0-nullsafety.1"
   stream_channel:
     dependency: transitive
     description:
       name: stream_channel
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "2.0.0"
+    version: "2.1.0-nullsafety.1"
   string_scanner:
     dependency: transitive
     description:
       name: string_scanner
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "1.0.5"
+    version: "1.1.0-nullsafety.1"
   term_glyph:
     dependency: transitive
     description:
       name: term_glyph
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "1.1.0"
+    version: "1.2.0-nullsafety.1"
   test_api:
     dependency: transitive
     description:
       name: test_api
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "0.2.15"
+    version: "0.2.19-nullsafety.2"
   typed_data:
     dependency: transitive
     description:
       name: typed_data
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "1.1.6"
+    version: "1.3.0-nullsafety.3"
   vector_math:
     dependency: transitive
     description:
       name: vector_math
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "2.0.8"
-  xml:
-    dependency: transitive
-    description:
-      name: xml
-      url: "https://pub.dartlang.org"
-    source: hosted
-    version: "3.6.1"
+    version: "2.1.0-nullsafety.3"
 sdks:
-  dart: ">=2.6.0 <3.0.0"
+  dart: ">=2.10.0-110 <2.11.0"
   flutter: ">=1.5.0 <2.0.0"

lib/src/mixpanel_analytics.dart

@@ -198,6 +198,14 @@ class MixpanelAnalytics {
         event, properties, time ?? DateTime.now(), ip, insertId);
 
     if (isBatchMode) {
+      // TODO: this should be place within an init() along within the constructor.
+      // This is not perfect, as we are waiting for the caller to send an event before sending the stored in memory.
+      // But doing it on an init() would be a breaking change.
+      // To be executed only the first time user tries to send an event
+      if (!_isQueuedEventsReadFromStorage) {
+        await _restoreQueuedEventsFromStorage();
+        _isQueuedEventsReadFromStorage = true;
+      }
       _trackEvents.add(trackEvent);
       return _saveQueuedEventsToLocalStorage();
     }
@@ -233,6 +241,14 @@ class MixpanelAnalytics {
         operation, value, time ?? DateTime.now(), ip, ignoreTime, ignoreAlias);
 
     if (isBatchMode) {
+      // TODO: this should be place within an init() along within the constructor.
+      // This is not perfect, as we are waiting for the caller to send an event before sending the stored in memory.
+      // But doing it on an init() would be a breaking change.
+      // To be executed only the first time user tries to send an event
+      if (!_isQueuedEventsReadFromStorage) {
+        await _restoreQueuedEventsFromStorage();
+        _isQueuedEventsReadFromStorage = true;
+      }
       _engageEvents.add(engageEvent);
       return _saveQueuedEventsToLocalStorage();
     }
@@ -266,10 +282,6 @@ class MixpanelAnalytics {
   // Tries to send all events pending to be send.
   // TODO if error when sending, send events in isolation identify the incorrect message
   Future<void> _uploadQueuedEvents() async {
-    if (!_isQueuedEventsReadFromStorage) {
-      await _restoreQueuedEventsFromStorage();
-      _isQueuedEventsReadFromStorage = true;
-    }
     await _uploadEvents(_trackEvents, _sendTrackBatch);
     await _uploadEvents(_engageEvents, _sendEngageBatch);
     await _saveQueuedEventsToLocalStorage();
@@ -312,7 +324,9 @@ class MixpanelAnalytics {
       'distinct_id': props['distinct_id'] == null
           ? _userId == null
               ? 'Unknown'
-              : _shouldAnonymize ? _anonymize('userId', _userId) : _userId
+              : _shouldAnonymize
+                  ? _anonymize('userId', _userId)
+                  : _userId
           : props['distinct_id']
     };
     if (ip != null) {
@@ -340,7 +354,9 @@ class MixpanelAnalytics {
       '\$distinct_id': value['distinct_id'] == null
           ? _userId == null
               ? 'Unknown'
-              : _shouldAnonymize ? _anonymize('userId', _userId) : _userId
+              : _shouldAnonymize
+                  ? _anonymize('userId', _userId)
+                  : _userId
           : value['distinct_id']
     };
     if (ip != null) {