api/admin: implement admin.vm.Stats

QubesOS/qubes-issues#853

Makefile

@@ -90,6 +90,7 @@ ADMIN_API_METHODS_SIMPLE = \
 	admin.vm.volume.ListSnapshots \
 	admin.vm.volume.Resize \
 	admin.vm.volume.Revert \
+	admin.vm.Stats \
 	$(null)
 
 ifeq ($(OS),Linux)

qubes/api/admin.py

@@ -1093,3 +1093,55 @@ def vm_firewall_reload(self):
         self.fire_event_for_permission()
 
         self.dest.fire_event('firewall-changed')
+
+    @qubes.api.method('admin.vm.Stats', no_payload=True,
+        scope='global', read=True)
+    @asyncio.coroutine
+    def vm_stats(self):
+        assert not self.arg
+
+        # run until client connection is terminated
+        self.cancellable = True
+
+        # cache event filters, to not call an event each time an event arrives
+        stats_filters = self.fire_event_for_permission()
+
+        only_vm = None
+        if self.dest.name != 'dom0':
+            only_vm = self.dest
+
+        info_time = None
+        info = None
+        id_to_name_map = {0: 'dom0'}
+        while True:
+            (info_time, info) = self.app.host.get_vm_stats(info_time, info,
+                only_vm=only_vm)
+            for vm_id, vm_info in info.items():
+                if vm_id not in id_to_name_map:
+                    try:
+                        name = \
+                            self.app.vmm.libvirt_conn.lookupByID(vm_id).name()
+                    except libvirt.libvirtError as err:
+                        if err.get_error_code() == libvirt.VIR_ERR_NO_DOMAIN:
+                            # stubdomain or so
+                            name = None
+                        else:
+                            raise
+                    id_to_name_map[vm_id] = name
+                else:
+                    name = id_to_name_map[vm_id]
+
+                # skip VMs with unknown name
+                if name is None:
+                    continue
+
+                if not list(qubes.api.apply_filters([name],
+                        stats_filters)):
+                    continue
+
+                self.send_event(name, 'vm-stats',
+                    memory_kb=int(vm_info['memory_kb']),
+                    cpu_time=int(vm_info['cpu_time'] / 1000000),
+                    cpu_usage=int(vm_info['cpu_usage']))
+
+            yield from asyncio.sleep(self.app.stats_update_interval)

qubes/app.py

@@ -706,6 +706,11 @@ class Qubes(qubes.PropertyHolder):
         default=lambda app: app.default_pool,
         doc='Default storage pool for kernel volumes')
 
+    stats_update_interval = qubes.property('stats_interval',
+        default=3,
+        type=int,
+        doc='Interval in seconds for VM stats reporting (memory, CPU usage)')
+
     # TODO #1637 #892
     check_updates_vm = qubes.property('check_updates_vm',
         type=bool, setter=qubes.property.bool,