Use a JSON encoding for percentile data being sent to analytics

Change-Id: Ie96f81e9cdc7585a5027db7b44f7f39cb7e763b8
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/247240
Reviewed-by: Phil Quitslund <[email protected]>
Commit-Queue: Brian Wilkerson <[email protected]>

Author: bwilkerson

pkg/analysis_server/lib/src/analytics/google_analytics_manager.dart

@@ -210,10 +210,10 @@ class _PluginData {
   }
 
   /// Return an encoding of the [usageCounts].
-  Map<String, String> _encodeUsageCounts() {
-    var encoded = <String, String>{};
+  Map<String, Object> _encodeUsageCounts() {
+    var encoded = <String, Object>{};
     for (var entry in usageCounts.entries) {
-      encoded[entry.key] = entry.value.toAnalyticsString();
+      encoded[entry.key] = entry.value.toJson();
     }
     return encoded;
   }

pkg/analysis_server/lib/src/analytics/percentile_calculator.dart

@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+import 'dart:convert';
+
 /// An object used to calculate percentile-based analytics.
 ///
 /// See https://en.wikipedia.org/wiki/Percentile.
@@ -52,18 +54,19 @@ class PercentileCalculator {
   }
 
   /// Return a string that is suitable for sending to the analytics service.
-  String toAnalyticsString() {
-    var buffer = StringBuffer();
-    buffer.write(_valueCount);
-    buffer.write('[');
+  String toAnalyticsString() => json.encode(toJson());
+
+  /// Return a map that can be encoded as JSON that represents the state of this
+  /// calculator.
+  Map<String, Object> toJson() {
+    var percentiles = <int>[];
     for (var p = 5; p <= 100; p += 5) {
-      if (p > 5) {
-        buffer.write(', ');
-      }
-      buffer.write(percentile(p));
+      percentiles.add(percentile(p));
     }
-    buffer.write(']');
-    return buffer.toString();
+    return {
+      'count': _valueCount,
+      'percentiles': percentiles,
+    };
   }
 
   @override

pkg/analysis_server/test/src/analytics/google_analytics_manager_test.dart

@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+import 'dart:convert';
+
 import 'package:analysis_server/protocol/protocol.dart';
 import 'package:analysis_server/src/analytics/google_analytics_manager.dart';
 import 'package:analysis_server/src/analytics/percentile_calculator.dart';
@@ -89,11 +91,11 @@ class GoogleAnalyticsManagerTest {
       _MockPluginInfo('b'),
     ]));
     manager.shutdown();
+    var counts =
+        '{"count":1,"percentiles":[0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0]}';
     analytics.assertEvents([
       _ExpectedEvent.session(parameters: {
-        'plugins': '{"recordCount":1,"rootCounts":{"a":"1[0, 0, 0, 0, 0, 0, '
-            '0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0]","b":"1[0, 0, 0, 0, 0, '
-            '0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0]"}}'
+        'plugins': '{"recordCount":1,"rootCounts":{"a":$counts,"b":$counts}}'
       }),
     ]);
   }
@@ -203,33 +205,21 @@ class _IsPercentiles extends Matcher {
 
   @override
   bool matches(Object? item, Map matchState) {
-    if (item is! String || !item.endsWith(']')) {
+    if (item is! String) {
       return false;
     }
-    var index = item.indexOf('[');
-    var count = item.substring(0, index);
-    if (!_isStringEncodedPositiveInt(count)) {
+    var map = json.decode(item);
+    if (map is! Map || map.length != 2) {
       return false;
     }
-    var percentiles = item.substring(index + 1, item.length - 1).split(', ');
-    if (percentiles.length != 20) {
+    if (map['count'] is! int) {
       return false;
     }
-    for (var percentile in percentiles) {
-      if (!_isStringEncodedPositiveInt(percentile)) {
-        return false;
-      }
-    }
-    return true;
-  }
-
-  bool _isStringEncodedPositiveInt(String item) {
-    try {
-      var value = int.parse(item);
-      return value >= 0;
-    } catch (exception) {
+    var percentiles = map['percentiles'];
+    if (percentiles is! List || percentiles.length != 20) {
       return false;
     }
+    return !percentiles.any((element) => element is! int);
   }
 }
 

pkg/analysis_server/test/src/analytics/percentile_calculator_test.dart

@@ -22,19 +22,19 @@ class PercentileCalculatorTest {
     }
     calculator.clear();
     expect(calculator.toAnalyticsString(),
-        '0[0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0]');
+        '{"count":0,"percentiles":[0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0]}');
   }
 
   void test_toAnalyticsString_empty() {
     expect(calculator.toAnalyticsString(),
-        '0[0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0]');
+        '{"count":0,"percentiles":[0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0]}');
   }
 
   void test_toAnalyticsString_evenDistribution() {
     for (int i = 1; i <= 100; i++) {
       calculator.addValue(i);
     }
     expect(calculator.toAnalyticsString(),
-        '100[5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95, 100]');
+        '{"count":100,"percentiles":[5,10,15,20,25,30,35,40,45,50,55,60,65,70,75,80,85,90,95,100]}');
   }
 }