telegraf/plugins/inputs/ethtool/namespace_linux.go

134 lines
3.6 KiB
Go

package ethtool
import (
"net"
"runtime"
ethtoolLib "github.com/safchain/ethtool"
"github.com/vishvananda/netns"
"github.com/influxdata/telegraf"
)
type NamespacedAction struct {
result chan<- NamespacedResult
f func(*NamespaceGoroutine) (interface{}, error)
}
type NamespacedResult struct {
Result interface{}
Error error
}
type NamespaceGoroutine struct {
name string
handle netns.NsHandle
ethtoolClient *ethtoolLib.Ethtool
c chan NamespacedAction
Log telegraf.Logger
}
func (n *NamespaceGoroutine) Name() string {
return n.name
}
func (n *NamespaceGoroutine) Interfaces() ([]NamespacedInterface, error) {
interfaces, err := n.Do(func(n *NamespaceGoroutine) (interface{}, error) {
interfaces, err := net.Interfaces()
if err != nil {
n.Log.Errorf(`Could not get interfaces in namespace "%s": %s`, n.name, err)
return nil, err
}
namespacedInterfaces := make([]NamespacedInterface, 0, len(interfaces))
for _, iface := range interfaces {
namespacedInterfaces = append(
namespacedInterfaces,
NamespacedInterface{
Interface: iface,
Namespace: n,
},
)
}
return namespacedInterfaces, nil
})
return interfaces.([]NamespacedInterface), err
}
func (n *NamespaceGoroutine) DriverName(intf NamespacedInterface) (string, error) {
driver, err := n.Do(func(n *NamespaceGoroutine) (interface{}, error) {
return n.ethtoolClient.DriverName(intf.Name)
})
return driver.(string), err
}
func (n *NamespaceGoroutine) Stats(intf NamespacedInterface) (map[string]uint64, error) {
driver, err := n.Do(func(n *NamespaceGoroutine) (interface{}, error) {
return n.ethtoolClient.Stats(intf.Name)
})
return driver.(map[string]uint64), err
}
// Start locks a goroutine to an OS thread and ties it to the namespace, then
// loops for actions to run in the namespace.
func (n *NamespaceGoroutine) Start() error {
n.c = make(chan NamespacedAction)
started := make(chan error)
go func() {
// We're going to hold this thread locked permanently. We're going to
// do this for every namespace. This makes it very likely that the Go
// runtime will spin up new threads to replace it. To avoid thread
// leaks, we don't unlock when we're done and instead let this thread
// die.
runtime.LockOSThread()
// If this goroutine is for the initial namespace, we are already in
// the correct namespace. Switching would require CAP_SYS_ADMIN, which
// we may not have. Don't switch if the desired namespace matches the
// current one.
initialNamespace, err := netns.Get()
if err != nil {
n.Log.Errorf("Could not get initial namespace: %s", err)
started <- err
return
}
if !initialNamespace.Equal(n.handle) {
if err := netns.Set(n.handle); err != nil {
n.Log.Errorf(`Could not switch to namespace "%s": %s`, n.name, err)
started <- err
return
}
}
// Every namespace needs its own connection to ethtool
e, err := ethtoolLib.NewEthtool()
if err != nil {
n.Log.Errorf(`Could not create ethtool client for namespace "%s": %s`, n.name, err)
started <- err
return
}
n.ethtoolClient = e
started <- nil
for command := range n.c {
result, err := command.f(n)
command.result <- NamespacedResult{
Result: result,
Error: err,
}
close(command.result)
}
}()
return <-started
}
// Do runs a function inside the OS thread tied to the namespace.
func (n *NamespaceGoroutine) Do(f func(*NamespaceGoroutine) (interface{}, error)) (interface{}, error) {
result := make(chan NamespacedResult)
n.c <- NamespacedAction{
result: result,
f: f,
}
r := <-result
return r.Result, r.Error
}