blob: 1d1831373a7c7634b28bf84ca184b2335aa38f2e [file] [log] [blame]
// Copyright (c) 2017, 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.
import 'dart:io';
/// A class that can return memory and cpu usage information for a given
/// process.
abstract class ProcessProfiler {
ProcessProfiler._();
Future<UsageInfo> getProcessUsage(int processId);
/// Return a [ProcessProfiler] instance suitable for the current host
/// platform. This can return `null` if we're not able to gather memory and
/// cpu information for the current platform.
static ProcessProfiler getProfilerForPlatform() {
if (Platform.isLinux || Platform.isMacOS) {
return _PosixProcessProfiler();
}
// Not a supported platform.
return null;
}
}
class UsageInfo {
/// A number between 0.0 and 100.0 * the number of host CPUs (but typically
/// never more than slightly above 100.0).
final double cpuPercentage;
/// The process memory usage in kilobytes.
final int memoryKB;
UsageInfo(this.cpuPercentage, this.memoryKB);
double get memoryMB => memoryKB / 1024;
@override
String toString() => '$cpuPercentage% ${memoryMB.toStringAsFixed(1)}MB';
}
class _PosixProcessProfiler extends ProcessProfiler {
static final RegExp stringSplitRegExp = RegExp(r'\s+');
_PosixProcessProfiler() : super._();
@override
Future<UsageInfo> getProcessUsage(int processId) {
try {
// Execution time is typically 2-4ms.
var future =
Process.run('ps', ['-o', '%cpu=,rss=', processId.toString()]);
return future.then((ProcessResult result) {
if (result.exitCode != 0) {
return Future.value(null);
}
return Future.value(_parse(result.stdout));
});
} catch (e) {
return Future.error(e);
}
}
UsageInfo _parse(String psResults) {
try {
// " 0.0 378940"
var line = psResults.split('\n').first.trim();
var values = line.split(stringSplitRegExp);
return UsageInfo(double.parse(values[0]), int.parse(values[1]));
} catch (e) {
return null;
}
}
}