windows_exporter/internal/initiate/initiate.go

99 lines
2.4 KiB
Go

// Package initiate allows us to initiate Time Sensitive components (Like registering the windows service) as early as possible in the startup process
package initiate
import (
"fmt"
"os"
"golang.org/x/sys/windows"
"golang.org/x/sys/windows/svc"
"golang.org/x/sys/windows/svc/eventlog"
)
const (
serviceName = "windows_exporter"
)
type windowsExporterService struct{}
func (s *windowsExporterService) Execute(_ []string, r <-chan svc.ChangeRequest, changes chan<- svc.Status) (bool, uint32) {
const cmdsAccepted = svc.AcceptStop | svc.AcceptShutdown
changes <- svc.Status{State: svc.StartPending}
changes <- svc.Status{State: svc.Running, Accepts: cmdsAccepted}
for {
select {
case exitCodeCh := <-ExitCodeCh:
changes <- svc.Status{State: svc.StopPending}
return true, uint32(exitCodeCh)
case c := <-r:
switch c.Cmd {
case svc.Interrogate:
changes <- c.CurrentStatus
case svc.Stop, svc.Shutdown:
_ = logToEventToLog(windows.EVENTLOG_INFORMATION_TYPE, "service stop received")
changes <- svc.Status{State: svc.StopPending}
return false, 0
default:
_ = logToEventToLog(windows.EVENTLOG_ERROR_TYPE, fmt.Sprintf("unexpected control request #%d", c))
}
}
}
}
var (
IsService bool
ExitCodeCh = make(chan int)
StopCh = make(chan struct{})
)
//nolint:gochecknoinits
func init() {
var err error
IsService, err = svc.IsWindowsService()
if err != nil {
err = logToEventToLog(windows.EVENTLOG_ERROR_TYPE, fmt.Sprintf("Failed to detect service: %v", err))
if err != nil {
os.Exit(2)
}
os.Exit(1)
}
if IsService {
err = logToEventToLog(windows.EVENTLOG_INFORMATION_TYPE, "Attempting to start exporter service")
go func() {
err = svc.Run(serviceName, &windowsExporterService{})
if err != nil {
_ = logToEventToLog(windows.EVENTLOG_ERROR_TYPE, fmt.Sprintf("Failed to start service: %v", err))
}
StopCh <- struct{}{}
}()
}
}
func logToEventToLog(eType uint16, msg string) error {
eventLog, err := eventlog.Open("windows_exporter")
if err != nil {
return fmt.Errorf("failed to open event log: %w", err)
}
defer func(eventLog *eventlog.Log) {
_ = eventLog.Close()
}(eventLog)
p, err := windows.UTF16PtrFromString(msg)
if err != nil {
return fmt.Errorf("error convert string to UTF-16: %w", err)
}
ss := []*uint16{p, nil, nil, nil, nil, nil, nil, nil, nil}
return windows.ReportEvent(eventLog.Handle, eType, 0, 3299, 0, 9, 0, &ss[0], nil)
}