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moby--moby/daemon/logger/etwlogs/etwlogs_windows.go
Daniel Nephin 4f0d95fa6e Add canonical import comment
Signed-off-by: Daniel Nephin <dnephin@docker.com>
2018-02-05 16:51:57 -05:00

168 lines
4.7 KiB
Go

// Package etwlogs provides a log driver for forwarding container logs
// as ETW events.(ETW stands for Event Tracing for Windows)
// A client can then create an ETW listener to listen for events that are sent
// by the ETW provider that we register, using the provider's GUID "a3693192-9ed6-46d2-a981-f8226c8363bd".
// Here is an example of how to do this using the logman utility:
// 1. logman start -ets DockerContainerLogs -p {a3693192-9ed6-46d2-a981-f8226c8363bd} 0 0 -o trace.etl
// 2. Run container(s) and generate log messages
// 3. logman stop -ets DockerContainerLogs
// 4. You can then convert the etl log file to XML using: tracerpt -y trace.etl
//
// Each container log message generates an ETW event that also contains:
// the container name and ID, the timestamp, and the stream type.
package etwlogs // import "github.com/docker/docker/daemon/logger/etwlogs"
import (
"errors"
"fmt"
"sync"
"unsafe"
"github.com/docker/docker/daemon/logger"
"github.com/sirupsen/logrus"
"golang.org/x/sys/windows"
)
type etwLogs struct {
containerName string
imageName string
containerID string
imageID string
}
const (
name = "etwlogs"
win32CallSuccess = 0
)
var (
modAdvapi32 = windows.NewLazySystemDLL("Advapi32.dll")
procEventRegister = modAdvapi32.NewProc("EventRegister")
procEventWriteString = modAdvapi32.NewProc("EventWriteString")
procEventUnregister = modAdvapi32.NewProc("EventUnregister")
)
var providerHandle windows.Handle
var refCount int
var mu sync.Mutex
func init() {
providerHandle = windows.InvalidHandle
if err := logger.RegisterLogDriver(name, New); err != nil {
logrus.Fatal(err)
}
}
// New creates a new etwLogs logger for the given container and registers the EWT provider.
func New(info logger.Info) (logger.Logger, error) {
if err := registerETWProvider(); err != nil {
return nil, err
}
logrus.Debugf("logging driver etwLogs configured for container: %s.", info.ContainerID)
return &etwLogs{
containerName: info.Name(),
imageName: info.ContainerImageName,
containerID: info.ContainerID,
imageID: info.ContainerImageID,
}, nil
}
// Log logs the message to the ETW stream.
func (etwLogger *etwLogs) Log(msg *logger.Message) error {
if providerHandle == windows.InvalidHandle {
// This should never be hit, if it is, it indicates a programming error.
errorMessage := "ETWLogs cannot log the message, because the event provider has not been registered."
logrus.Error(errorMessage)
return errors.New(errorMessage)
}
m := createLogMessage(etwLogger, msg)
logger.PutMessage(msg)
return callEventWriteString(m)
}
// Close closes the logger by unregistering the ETW provider.
func (etwLogger *etwLogs) Close() error {
unregisterETWProvider()
return nil
}
func (etwLogger *etwLogs) Name() string {
return name
}
func createLogMessage(etwLogger *etwLogs, msg *logger.Message) string {
return fmt.Sprintf("container_name: %s, image_name: %s, container_id: %s, image_id: %s, source: %s, log: %s",
etwLogger.containerName,
etwLogger.imageName,
etwLogger.containerID,
etwLogger.imageID,
msg.Source,
msg.Line)
}
func registerETWProvider() error {
mu.Lock()
defer mu.Unlock()
if refCount == 0 {
var err error
if err = callEventRegister(); err != nil {
return err
}
}
refCount++
return nil
}
func unregisterETWProvider() {
mu.Lock()
defer mu.Unlock()
if refCount == 1 {
if callEventUnregister() {
refCount--
providerHandle = windows.InvalidHandle
}
// Not returning an error if EventUnregister fails, because etwLogs will continue to work
} else {
refCount--
}
}
func callEventRegister() error {
// The provider's GUID is {a3693192-9ed6-46d2-a981-f8226c8363bd}
guid := windows.GUID{
Data1: 0xa3693192,
Data2: 0x9ed6,
Data3: 0x46d2,
Data4: [8]byte{0xa9, 0x81, 0xf8, 0x22, 0x6c, 0x83, 0x63, 0xbd},
}
ret, _, _ := procEventRegister.Call(uintptr(unsafe.Pointer(&guid)), 0, 0, uintptr(unsafe.Pointer(&providerHandle)))
if ret != win32CallSuccess {
errorMessage := fmt.Sprintf("Failed to register ETW provider. Error: %d", ret)
logrus.Error(errorMessage)
return errors.New(errorMessage)
}
return nil
}
func callEventWriteString(message string) error {
utf16message, err := windows.UTF16FromString(message)
if err != nil {
return err
}
ret, _, _ := procEventWriteString.Call(uintptr(providerHandle), 0, 0, uintptr(unsafe.Pointer(&utf16message[0])))
if ret != win32CallSuccess {
errorMessage := fmt.Sprintf("ETWLogs provider failed to log message. Error: %d", ret)
logrus.Error(errorMessage)
return errors.New(errorMessage)
}
return nil
}
func callEventUnregister() bool {
ret, _, _ := procEventUnregister.Call(uintptr(providerHandle))
return ret == win32CallSuccess
}