forked from kubevirt/kubevirt
/
device_controller.go
146 lines (124 loc) · 3.4 KB
/
device_controller.go
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/*
* This file is part of the KubeVirt project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*
* Copyright 2018 Red Hat, Inc.
*
*/
package device_manager
import (
"fmt"
"os"
"path/filepath"
"github.com/fsnotify/fsnotify"
"kubevirt.io/kubevirt/pkg/log"
)
const (
KVMPath = "/dev/kvm"
KVMName = "kvm"
TunPath = "/dev/net/tun"
TunName = "tun"
VhostNetPath = "/dev/vhost-net"
VhostNetName = "vhost-net"
)
type DeviceController struct {
devicePlugins []GenericDevice
host string
maxDevices int
}
func NewDeviceController(host string, maxDevices int) *DeviceController {
return &DeviceController{
devicePlugins: []GenericDevice{
NewGenericDevicePlugin(KVMName, KVMPath, maxDevices),
NewGenericDevicePlugin(TunName, TunPath, maxDevices),
NewGenericDevicePlugin(VhostNetName, VhostNetPath, maxDevices),
},
host: host,
maxDevices: maxDevices,
}
}
func (c *DeviceController) nodeHasDevice(devicePath string) bool {
_, err := os.Stat(devicePath)
// Since this is a boolean question, any error means "no"
return (err == nil)
}
func (c *DeviceController) waitForPath(target string, stop chan struct{}) error {
logger := log.DefaultLogger()
_, err := os.Stat(target)
if err != nil {
if !os.IsNotExist(err) {
return err
}
} else {
// File already exists, so there's nothing to wait for
return nil
}
watcher, err := fsnotify.NewWatcher()
if err != nil {
return err
}
defer watcher.Close()
// Can't watch for a nonexistent file, so watch the parent directory
dirName := filepath.Dir(target)
_, err = os.Stat(dirName)
if err != nil {
// If the parent directory doesn't exist, there's nothing to watch
return err
}
err = watcher.Add(dirName)
if err != nil {
logger.Errorf("Error adding path to watcher: %v", err)
return err
}
for {
select {
case event := <-watcher.Events:
if (event.Op == fsnotify.Create) && (event.Name == target) {
return nil
}
case <-stop:
return fmt.Errorf("shutting down")
}
}
}
func (c *DeviceController) startDevicePlugin(dev GenericDevice, stop chan struct{}) error {
logger := log.DefaultLogger()
devicePath := dev.GetDevicePath()
deviceName := dev.GetDeviceName()
if !c.nodeHasDevice(devicePath) {
logger.Infof("%s device not found. Waiting.", deviceName)
err := c.waitForPath(devicePath, stop)
if err != nil {
logger.Errorf("error waiting for %s device: %v", deviceName, err)
return err
}
}
err := dev.Start(stop)
if err != nil {
logger.Errorf("Error starting %s device plugin: %v", deviceName, err)
return err
}
logger.Infof("%s device plugin started", deviceName)
return nil
}
func (c *DeviceController) Run(stop chan struct{}) error {
logger := log.DefaultLogger()
logger.Info("Starting device plugin controller")
for _, dev := range c.devicePlugins {
go c.startDevicePlugin(dev, stop)
}
<-stop
logger.Info("Shutting down device plugin controller")
return nil
}