vb.net - System.IO.IOException: The process cannot access the file -
hi programmers colleagues! hope know how solve issue. time time not error in subject when writing log file. got 3 windows services in solution. using same file logs. unfortunetly time time error. code logger showed below. used synlock , thought enough not. can me should change avoid issue please?:
public notinheritable class logger private shared readonly _locker new object() public shared sub logit(byval engine string, byval msg string, byval logmessage string, byval path string, byval isdebug boolean) if file.exists(path) if isdebug debug.print(datetime.now & "> " & "| " & engine & " | " & msg & " | " & logmessage) ' debug.print(message) else synclock _locker using w textwriter = file.appendtext(path) 'w.writeline(message) w.writeline(datetime.now & "> " & "| " & engine & " | " & msg & " | " & logmessage) w.flush() end using end synclock end if else if isdebug ' debug.print(message) debug.print(datetime.now & "> " & "| " & engine & " | " & msg & " | " & logmessage) else synclock _locker using w textwriter = file.createtext(path) ' w.writeline(message) w.writeline(datetime.now & "> " & "| " & engine & " | " & msg & " | " & logmessage) w.flush() end using end synclock end if end if end sub end class updated:
imports system.io imports system.threading public notinheritable class logger private shared readonly _locker new mutex(false, "global\anyhardtoguessname") public shared sub logit(byval engine string, byval msg string, byval logmessage string, byval path string, byval isdebug boolean) _locker.waitone() try if file.exists(path) if isdebug debug.print(datetime.now & "> " & "| " & engine & " | " & msg & " | " & logmessage) ' debug.print(message) else using w textwriter = file.appendtext(path) 'w.writeline(message) w.writeline(datetime.now & "> " & "| " & engine & " | " & msg & " | " & logmessage) w.flush() end using end if else if isdebug ' debug.print(message) debug.print(datetime.now & "> " & "| " & engine & " | " & msg & " | " & logmessage) else using w textwriter = file.createtext(path) ' w.writeline(message) w.writeline(datetime.now & "> " & "| " & engine & " | " & msg & " | " & logmessage) w.flush() end using end if end if _locker.releasemutex() end try end sub end class
i got 3 windows services in solution
that produces 3 separate exes, not share _locker object. visibility of .net objects restricted process in created. nothing prevents these programs trying open log file @ same time. or trying create log file @ same time, have bug in file.exists usage, must inside synclock statement prevent race when 2 threads both check file existence @ same time.
by far best solution have each exe use own log file _locker object enough. if sharing absolutely essential must use named mutex allow these programs share same synchronization object across process boundaries. in other words:
private shared readonly _locker new mutex(false, "global\anyhardtoguessname") public shared sub logit(...) _locker.waitone() try ''... _locker.releasemutex() end try end sub add imports system.threading @ top of source file.
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