[RESOLVED] [2005] Running the handler once on OnStart of a Service

[rashley]

I've put off posting this one for a while, as I know related subjects hav been discussed, but I just can't seem to get it working.

I have a service with a FileSystemWatcher:

Public Class RightHemisphereLoader
    Private watcher As IO.FileSystemWatcher
    Private zipfile As ICSharpCode.SharpZipLib.Zip.ZipFile
    Private utils As New RHUtils.RHUtils
    Protected Overrides Sub OnStart(ByVal args() As String)

           Try
            ' Add code here to start your service. This method should set things
            ' in motion so your service can do its work.

            'At this point we've processed what's there.
            'Set up our watcher for LCA data
            watcher = New IO.FileSystemWatcher
            watcher.Path = utils.setting("InputDirectory")
            watcher.Filter = "*.zip"
            watcher.IncludeSubdirectories = True
            watcher.NotifyFilter = NotifyFilters.FileName
            AddHandler watcher.Created, AddressOf loadRHviaDirectoryWatcher

            'Begin watching
            watcher.EnableRaisingEvents = True
            utils.WriteLog("Service and directory watcher started.", "OnStart", "Info")

            'In case there's stuff there, clean and raise the event
            cleanDir(utils.setting("WorkingDirectory"))



        Catch ex As Exception
            utils.WriteLog(ex.Message(), "OnStart", "ERROR")
        End Try
    End Sub

What I'm trying to do is call the loadRHviaDirectoryWatcher once to process any files that are already there. Trouble is, that processing often takes hours, and OnStart has to finish in 30 seconds or the service fails to start.

I've tried creating a custom event that loadRHviaDirectoryWatcher handles and raising it, but then the AddHandler line complains.

How is this best accomplished? Thanks!

[techgnome]

I'd probably do it by spinning up a timer at the end of the OnStart... then when the timer expires, call the method to process existing files.

-tg

[kleinma]

if processing takes hours, why not offload all the processing to seperate threads?

[rashley]

Thanks for the suggestions.

I'll try the timer idea.

I don't want to thread it because if multiple files process at once there are issues due to the nature of the data I'm processing.

[rashley]

Got it. Threading the function did work, but I had to make a wrapper function for the directory watcher.

   Protected Overrides Sub OnStart(ByVal args() As String)

        'End Sub
        'Public Sub OnStart2()
        Try
            ' Add code here to start your service. This method should set things
            ' in motion so your service can do its work.

            Dim t As Threading.Thread
            Dim tm As New ThreadMethods

            'At this point we've processed what's there.
            'Set up our watcher for LCA data
            watcher = New IO.FileSystemWatcher
            watcher.Path = utils.setting("InputDirectory")
            watcher.Filter = "*.zip"
            watcher.IncludeSubdirectories = True
            watcher.NotifyFilter = NotifyFilters.FileName
            AddHandler watcher.Created, AddressOf tm.loadRHviaDirectoryWatcherWrapper

            'Begin watching
            watcher.EnableRaisingEvents = True
            utils.WriteLog("Service and directory watcher started.", "OnStart", "Info")

            'In case there's stuff there, clean and raise the event
            tm.watcher = watcher
            tm.utils = utils
            tm.cleanDir(utils.setting("WorkingDirectory"))
            'Fork the process
            t = New Threading.Thread(AddressOf tm.loadRHviaDirectoryWatcher)
            t.Start()


        Catch ex As Exception
            utils.WriteLog(ex.Message(), "OnStart", "ERROR")
        End Try
    End Sub
    Public Class ThreadMethods
        Public watcher As IO.FileSystemWatcher
        Public utils As RHUtils.RHUtils

        'Wrapper to handle the stupid source/e thing
        Public Sub loadRHviaDirectoryWatcherWrapper(ByVal source As Object, ByVal e As FileSystemEventArgs)
            loadRHviaDirectoryWatcher()
        End Sub

        'This gets called when a new zip file lands in our watched directory
        Public Sub loadRHviaDirectoryWatcher()
            Try

                'Stop the watcher
                watcher.EnableRaisingEvents = False

                'Grab last file.
                Dim nextFileName = getNextFileName(utils.setting("InputDirectory"))
                If (nextFileName = "0") Then
                    Exit Sub
                End If

                'Wait until we're sure the FTP is done
                While utils.IsFileInUse(utils.setting("InputDirectory") & nextFileName)
                    System.Threading.Thread.Sleep(1000) ' Sleep for 1 second
                End While

                'Process the File
                processZipFile(nextFileName)

                'Check for more files that may have shown up in the meantime and process in order
                nextFileName = getNextFileName(utils.setting("InputDirectory"))
                While (nextFileName <> "0")
                    processZipFile(nextFileName)
                    nextFileName = getNextFileName(utils.setting("InputDirectory"))
                End While

                'At this point the directory is empty, so we can restart the watcher
                watcher.EnableRaisingEvents = True
            Catch ex As Exception
                utils.WriteLog(ex.Message(), "loadRHviaDirectoryWatcher", "ERROR")
            End Try
        End Sub
End Class