Incremental log file function...

[opiate]

Can someone give me ideals on how to code a function that will create log files each time my app runs and increment the log file name each time it creates a new one. Like so…

0001.log
0002.log
0003.log
0004.log
0005.log

I’m creating a program that pulls data from one database and insert the data into another. Each time a new record is inserted while looping through a recordset, my app will write the insert statement to the log file.

Thanks for any help.

Corey

[ShadowKing]

here is part a subroutine that I wrote for a vbs script that synchronizes folders (http://www.mattlowe.com/files/distmaster.vbs). It was for a production system, so I had to handle all the errors and do reporting. This sub does basically what you want, except it has a preceding name for the file (like Joe(7).log). Anyway I have bolded the parts that should interest you. If you will tell me the language you want it in, I could probably see what I could do...


Sub saveLog(myLog, logSpot)
On Error Resume Next
If Not Right(logSpot, 1) = "\" Then logSpot = logSpot & "\"
myFile = logSpot & "SynchLog.htm"
If fs.FileExists(myFile) Then
m = 1
While fs.FileExists(logSpot & "SynchLog(" & m & ").htm")
m = m + 1
Wend
myFile = logSpot & "SynchLog(" & m & ").htm"
End If
Set Handle = fs.OpenTextFile(myFile, 2, True) 'save the file
Handle.WriteLine "A bunch of HTML code that doesn't work on Windrivers forums..."
Handle.Close
If Err.Number <> 0 Then 'The user entered an invalid location to save the error
If showError Then MsgBox "Error saving. File saved to c:\SynchLog.htm", , "Default Log Location"
myFile = "c:\SynchLog.htm"
Set Handle = fs.OpenTextFile(myFile, 2, True) 'save the new file
Handle.WriteLine "A bunch of HTML code that doesn't work on Windrivers forums..."
Handle.Close
End If
On Error goto 0
End Sub

Hope that helps.

[ShadowKing]

Here is a stright VB Function that will do what you want. You can even copy and paste it into your project and just call it...


Private Function GetLogName(Preface As String, Optional DestFolder As String) As String
Dim n As Integer 'counter
If DestFolder = "" Then DestFolder = App.Path 'Check to see if they passed the variable
If Right(DestFolder, 1) <> "\" Then DestFolder = DestFolder & "\" 'Format it properly

n = 1
While Dir(DestFolder & Preface & Right("000", 3 - (n \ 10)) & n & ".log") <> ""
n = n + 1
Wend

GetLogName = Preface & Right("000", 3 - (n \ 10)) & n & ".log"

End Function

[opiate]

I'm using VB6 SP4

[opiate]

so I just call it like so

set fs = CreateObject("Scripting.FileSystemObject")
set a = fs.CreateTextFile((GetLogName, Preface, DestFolder), False)

I don't under stand how I call it. What is Preface? Sorry, I'm not very good with functions.

[antonye]

There are two ways to attack this:

1. Create a filename to a certain scheme then see if it exists, incrementing until you find one that doesn't

or

2. Search for the last filename, then increment it

The advantage with (1) is that it will be relatively easy to code, but the problem is that as you fill your directory up with filenames, it will take longer to find the next file.

The advantage with (2) is that it will be quick to return your next filename, but a bit more tricky to code.

A good solution would be to narrow down the amount of searching by using the date as a prefix to the front of the file.

For example, your log files would be in the format:

LOG_YYYYMMDD_NN

Where:
YYYY = Year
MM = Month
DD = Day
NN = an incremented number

So your routine would look something like:


Function CreateLogFilename() as String
Dim sFilename as String
Dim lNumber as Long
Dim fso as Scripting.FileSystemObject



' create an FSO object
Set fso = CreateObject("Scripting.FileSystemObject")



' generate a filename first
sFilename = "C:\Logs\LOG_" & Format(Now(), "YYYYMMDD" & "_"



' start the number at 1
lNumber = 1



' see if this file exists
While NOT fso.FileExists(sFilename & lNumber & ".log")
' it does, so increment the number
lNumber = lNumber + 1
wend



' this file doesn't exist, so return it
CreateLogFilename = sFilename & lNumber & ".log"



end function


See the FileSystemObject (http://msdn.microsoft.com/library/default.asp?URL=/library/devprods/vs6/vbasic/vbenlr98/vaobjFileSystemObject.htm) pade on MSDN for the details.

HTH,

[opiate]

here is what I have and it's not working

Const Preface = "SLXIMPORT"
Const DestFolder = "C:\TEMP"

Private Sub Command1_Click()
strfile = GetLogName(Preface, DestFolder)
Set fs = CreateObject("Scripting.FileSystemObject")
Set a = fs.CreateTextFile(strfile, False, False)
a.Write "Test"
a.Close
Set fs = Nothing
Set a = Nothing

End Sub

Private Function GetLogName(Preface As String, Optional DestFolder As String) As String
Dim n As Integer 'counter
If DestFolder = "" Then DestFolder = App.Path 'Check to see if they passed the variable
If Right(DestFolder, 1) <> "\" Then DestFolder = DestFolder & "\" 'Format it properly
MsgBox DestFolder
n = 1
While Dir(DestFolder & Preface & Right("000", 3 - (n \ 10)) & n & ".log") <> ""
n = n + 1
Wend
MsgBox DestFolder & Preface & Right("000", 3 - (n \ 10)) & n & ".log"
GetLogName = Preface & Right("000", 3 - (n \ 10)) & n & ".log"

End Function

The function looks to the DestFolder to calculate the filename. Then when it creates the file it creates it in the app.path.

I get runtime "58" file exist. If I do not specify the Preface or DestFolder it works but creates the files in app.path

[antonye]

DestFolder = DestFolder & "\"


I don't think you can do this because, by default, you're passing over DestFolder as By Value (ByVal) rather than By Reference (ByRef).

You could tidy your code like this instead:

Private Function GetLogName(ByVal Preface As String, Optional DestFolder As String) As String



Dim sFilename as String
Dim sNumber as String
Dim lNumber As Long



If DestFolder = "" Then
&nbsp; sFilename = App.Path
Else
&nbsp; sFilename = DestFolder
End If



If Right(sFilename, 1) <> "\" Then
&nbsp; sFilename = sFilename & "\"
End If



lNumber = 1
sFilename = Preface & sFilename
sNumber = Right("000", 3 - (lNumber \ 10)) & lNumber & ".log"



While Dir(sFilename & sNumber) <> ""
&nbsp; lNumber = lNumber + 1
&nbsp; sNumber = Right("000", 3 - (lNumber \ 10)) & lNumber & ".log"
Wend



GetLogName = sFilename & sNumber



End Function


You may find this works...

[opiate]

antonye,

I'm using your example with a few changes. I put the date before the incremental characters. It looks something like so..

[Preface] [Date] [sNumber]
SLXImport - 06/8/01 - 001.log
SLXImport - 06/8/01 - 002.log
SLXImport - 06/8/01 - 003.log

This works great but there is a bug. It will only increment to..
SLXImport - 06/8/01 - 39.log

If I change...
sNumber = Right("000", 3 - (sNumber\10)) & sNumber & ".log"
..to
sNumber = Right("0000", 4 - (sNumber\10)) & sNumber & ".log"

This will allow for the increment to reach..
SLXImport - 06/8/01 - 49.log

Workaround..
If the date changes it will start back over to
SLXImport - 06/9/01 - 0001.log.

I'm just curious to see how we could fix this. If I reach 39 log files in 1 day I will be screwed.

Any ideals?

Thanks for all your help <IMG SRC="smilies/biggrin.gif" border="0">

[antonye]

You'd be better off creating your number like this:


sNumber = Format(lNumber, "0000")


This will format your number as a string into 4 digits, with any leading zeros if required.

This is a much neater way of doing it!

See the MSDN Format function (http://msdn.microsoft.com/library/devprods/vs6/vbasic/vbenlr98/vafctFormat.htm) for full details, with the User Defined Numeric Formats (http://msdn.microsoft.com/library/devprods/vs6/vbasic/vbenlr98/vafmtuserdefinednumericformats.htm) page for help.

[opiate]

Thanks man, I figured it out...