Initial UI for Metrics in Observatory

runtime/bin/vmservice/observatory/lib/src/service/object.dart

 // Copyright (c) 2014, the Dart project authors.  Please see the AUTHORS file
 // 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.
 
 part of service;
 
 /// A [ServiceObject] is an object known to the VM service and is tied
 /// to an owning [Isolate].
 abstract class ServiceObject extends Observable {
   static int LexicalSortName(ServiceObject o1, ServiceObject o2) {
@@ skipping 58 matching lines @@
     var type = _stripRef(map['type']);
     var obj = null;
     assert(type != 'VM');
     switch (type) {
       case 'Class':
         obj = new Class._empty(owner);
         break;
       case 'Code':
         obj = new Code._empty(owner);
         break;
+      case 'Counter':
+        obj = new Metric._empty(owner);
+        break;
       case 'Error':
         obj = new DartError._empty(owner);
         break;
       case 'Function':
         obj = new ServiceFunction._empty(owner);
         break;
+      case 'Gauge':
+        obj = new Metric._empty(owner);
+        break;
       case 'Isolate':
         obj = new Isolate._empty(owner.vm);
         break;
       case 'Library':
         obj = new Library._empty(owner);
         break;
       case 'ServiceError':
         obj = new ServiceError._empty(owner);
         break;
       case 'ServiceEvent':
@@ skipping 595 matching lines @@
     return new Future.value(objectClass);
   }
 
   ServiceObject getFromMap(ObservableMap map) {
     if (map == null) {
       return null;
     }
     String id = map['id'];
     var obj = _cache[id];
     if (obj != null) {
+      // Consider calling update when map is not a reference.
       return obj;
     }
     // Build the object from the map directly.
     obj = new ServiceObject._fromMap(this, map);
     if (obj != null && obj.canCache) {
       _cache[id] = obj;
     }
     return obj;
   }
 
@@ skipping 292 matching lines @@
     return get("debug/resume").then((result) {
         if (result is DartError) {
           // TODO(turnidge): Handle this more gracefully.
           Logger.root.severe(result.message);
         }
         return isolate.reload();
       });
   }
 
   Future stepInto() {
-    print('isolate.stepInto');
     return get("debug/resume?step=into").then((result) {
         if (result is DartError) {
           // TODO(turnidge): Handle this more gracefully.
           Logger.root.severe(result.message);
         }
         return isolate.reload();
       });
   }
 
   Future stepOver() {
     return get("debug/resume?step=over").then((result) {
         if (result is DartError) {
           // TODO(turnidge): Handle this more gracefully.
           Logger.root.severe(result.message);
         }
         return isolate.reload();
       });
   }
 
   Future stepOut() {
     return get("debug/resume?step=out").then((result) {
         if (result is DartError) {
           // TODO(turnidge): Handle this more gracefully.
           Logger.root.severe(result.message);
         }
         return isolate.reload();
       });
   }
+
+  final ObservableMap<String, Metric> metrics =
+      new ObservableMap<String, Metric>();
+
+  Future<ObservableMap<String, Metric>> refreshMetrics() {
+    return get('metrics').then((result) {
+      if (result is DartError) {
+        // TODO(turnidge): Handle this more gracefully.
+        Logger.root.severe(result.message);
+      }
+      // Clear metrics map.
+      metrics.clear();
+      // Repopulate metrics map.
+      var members = result['members'];
+      for (var metric in members) {
+        metrics[metric.name] = metric;
+      }
+    });
+  }
 }
 
 /// A [ServiceObject] which implements [ObservableMap].
 class ServiceMap extends ServiceObject implements ObservableMap {
   final ObservableMap _map = new ObservableMap();
   static String objectIdRingPrefix = 'objects/';
 
   bool get canCache {
     return (_serviceType == 'Class' ||
             _serviceType == 'Function' ||
@@ skipping 457 matching lines @@
         if (!_isTrivialToken(token)) {
           return false;
         }
       }
     }
     return true;
   }
 
   ScriptLine(this.script, this.line, this.text) {
     possibleBpt = !_isTrivialLine(text);
-    
+
     // TODO(turnidge): This is not so efficient.  Consider improving.
     for (var bpt in this.script.isolate.breakpoints['breakpoints']) {
       var bptScript = bpt['location']['script'];
       var bptTokenPos = bpt['location']['tokenPos'];
       if (bptScript == this.script &&
           bptScript.tokenToLine(bptTokenPos) == line) {
         this.bpt = bpt;
       }
     }
   }
@@ skipping 657 matching lines @@
     localAddress = map['localAddress'];
     localPort = map['localPort'];
     remoteAddress = map['remoteAddress'];
     remotePort = map['remotePort'];
 
     fd = map['fd'];
     socketOwner = map['owner'];
   }
 }
 
+class MetricSample {
+  final double value;
+  final DateTime time;
+  MetricSample(this.value) : time = new DateTime.now();
+}
+
+class Metric extends ServiceObject {
+  Metric._empty(ServiceObjectOwner owner) : super._empty(owner) {
+  }
+
+  bool get canCache => true;
+  bool get immutable => false;
+
+  @observable bool recording = false;
+  MetricPoller poller;
+
+  // 8 seconds, 4 seconds, 2 seconds, 1 second, and one hundred milliseconds.
+  static final List<int> pollPeriods = [8000, 4000, 2000, 1000, 100];

[koda, 2014/08/11 16:34:53]

Couldn't you traverse the DOM to get this list instead of hard-coding it?

If you need it, it should be const POLL_PERIODS.

[Cutch, 2014/08/27 22:25:40]

The service library doesn't import dart:html. Also, traversing the DOM requires
waiting for Polymer to "settle" and then traverse- which is heavy. I've moved
this into the MetricsPage (it didn't belong here) but am still not traversing
the DOM.
Done.

+
+  final ObservableList<MetricSample> samples =
+      new ObservableList<MetricSample>();
+  int _sampleBufferSize = 100;
+  int get sampleBufferSize => _sampleBufferSize;
+  set sampleBufferSize(int size) {
+    _sampleBufferSize = size;
+    _removeOld();
+  }
+
+  void addSample(MetricSample sample) {
+    samples.add(sample);
+    _removeOld();
+  }
+
+  void _removeOld() {
+    if (samples.length > _sampleBufferSize) {
+      int count = samples.length - _sampleBufferSize;
+      samples.removeRange(0, count);

[koda, 2014/08/11 16:34:54]

I assume ObservableList is backed by an array? If you have many large buffers,
the quadratic behavior might become costly.

At least remark that using a circular buffer is possible if needed.

[Cutch, 2014/08/27 22:25:40]

Done.

+    }
+  }
+
+  @observable String description;
+  @observable double value = 0.0;
+  @observable double min;
+  @observable double max;
+
+  bool get isGauge => (min != null) && (max != null);

[koda, 2014/08/11 16:34:53]

The fact that 'null' is valid and has this particular meaning should also be
noted on the fields themselves, since it's not obvious (+/-inf would be another
option).

Did you consider having Counter and Gauge subclasses? (Encoding types with
special values is fine if it's internal only, but in this case, it becomes part
of the interface.)

[Cutch, 2014/08/27 22:25:40]

Noted.
Yes, I've considered it and may do this in the future. For now the distinction
is a minor one- proper gauge support will come in a follow up CL and at that
point I may make distinct Counter and Gauge types.

+
+  void _update(ObservableMap map, bool mapIsRef) {
+    name = map['name'];
+    description = map['description'];
+    vmName = map['name'];
+    value = map['value'];
+    min = map['min'];
+    max = map['max'];
+  }
+}
+
+class MetricPoller {
+  // Metrics to be polled.
+  final List<Metric> metrics = new List<Metric>();
+  final int period;

[koda, 2014/08/11 16:34:54]

Redundant? In any case, avoid untyped times (or at least add "Ms" suffix).

[Cutch, 2014/08/27 22:25:40]

Redundant. Removed.

+  final Duration _pollPeriod;
+  Timer _pollTimer;
+
+  MetricPoller(int milliseconds) :
+      period = milliseconds,
+      _pollPeriod = new Duration(milliseconds: milliseconds) {
+    start();
+  }
+
+  void start() {
+    _pollTimer = new Timer.periodic(_pollPeriod, _onPoll);
+  }
+
+  void cancel() {
+    if (_pollTimer != null) {
+      _pollTimer.cancel();
+    }
+    _pollTimer = null;
+  }
+
+  void _onPoll(_) {
+    if (metrics.length == 0) {

[koda, 2014/08/11 16:34:53]

Redundant.

[Cutch, 2014/08/27 22:25:40]

Done.

+      return;
+    }
+    // Reload metrics and add a sample to each.
+    for (var i = 0; i < metrics.length; i++) {

[koda, 2014/08/11 16:34:53]

Use for-in when possible.

[Cutch, 2014/08/27 22:25:40]

Done.

+      var metric = metrics[i];
+      metric.reload().then((m) {
+        m.addSample(new MetricSample(m.value));
+      });
+    }
+  }
+}
+
 // Convert any ServiceMaps representing a null instance into an actual null.
 _convertNull(obj) {
   if (obj is ServiceMap &&
       obj.serviceType == 'Null') {
     return null;
   }
   return obj;
 }
 
 // Returns true if [map] is a service map. i.e. it has the following keys:
@@ skipping 36 matching lines @@
     var v = list[i];
     if ((v is ObservableMap) && _isServiceMap(v)) {
       list[i] = owner.getFromMap(v);
     } else if (v is ObservableList) {
       _upgradeObservableList(v, owner);
     } else if (v is ObservableMap) {
       _upgradeObservableMap(v, owner);
     }
   }
 }