Merge pull request #1256 from breed808/fix_msi_flag

fix: Set correct eventlog flag for MSI installer

installer/windows_exporter.wxs

@@ -52,7 +52,7 @@
             <fw:RemoteAddress>[REMOTE_ADDR]</fw:RemoteAddress>
           </fw:FirewallException>
         </File>
-        <ServiceInstall Id="InstallExporterService" Name="windows_exporter" DisplayName="windows_exporter" Description="Exports Prometheus metrics about the system" ErrorControl="normal" Start="auto" Type="ownProcess" Arguments="--log.format eventlog [CollectorsFlag] [ListenFlagBoth] [ListenFlagAddr] [ListenFlagPort] [MetricsPathFlag] [TextfileDirFlag] [ExtraFlags]">
+        <ServiceInstall Id="InstallExporterService" Name="windows_exporter" DisplayName="windows_exporter" Description="Exports Prometheus metrics about the system" ErrorControl="normal" Start="auto" Type="ownProcess" Arguments="--log.file eventlog [CollectorsFlag] [ListenFlagBoth] [ListenFlagAddr] [ListenFlagPort] [MetricsPathFlag] [TextfileDirFlag] [ExtraFlags]">
           <util:ServiceConfig FirstFailureActionType="restart" SecondFailureActionType="restart" ThirdFailureActionType="restart" RestartServiceDelayInSeconds="60" />
           <ServiceDependency Id="wmiApSrv" />
         </ServiceInstall>

log/logger.go

@@ -24,6 +24,7 @@ func (f *AllowedFile) String() string {
 
 // Set updates the value of the allowed format.
 func (f *AllowedFile) Set(s string) error {
+	f.s = s
 	switch s {
 	case "stdout":
 		f.w = os.Stdout
@@ -77,6 +78,8 @@ func New(config *Config) (log.Logger, error) {
 			return nil, err
 		}
 		l = eventlog.NewEventLogLogger(w, loggerFunc)
+	} else if config.File.w == nil {
+		panic("logger: file writer is nil")
 	} else {
 		l = loggerFunc(log.NewSyncWriter(config.File.w))
 	}