Parasitemia/Logger/Logger.fs

   1 namespace Logger
   2
   3 open System
   4 open System.Text
   5 open System.IO
   6 open System.Diagnostics
   7 open System.Threading
   8 open System.Collections.Generic
   9
  10 type Severity = DEBUG = 1 | USER = 2 | WARNING = 3 | ERROR = 4 | FATAL = 5
  11
  12 type IListener = abstract NewEntry : Severity -> string -> unit
  13
  14 [<Sealed>]
  15 type Log () =
  16     let maxSizeFile = 10L * 1024L * 1024L // [byte] (10 MB).
  17     let nbEntriesCheckSize = 100; // Each 100 entries added we check the size of the log file to test if it is greater than 'MAX_SIZE_FILE'.
  18     let LogDefaultDirectory = "Parasitemia\\Log"
  19     let filenameFormat = "{0:D4}.log"
  20     let encoding = Encoding.GetEncoding("UTF-8")
  21
  22     let moduleName = System.Diagnostics.StackFrame(1).GetMethod().Module.Name
  23
  24     let mutable stream: StreamWriter = null
  25
  26     let mutable logDir: string = null
  27     let mutable absoluteDir: string = null
  28
  29     let mutable nbEntries = 0L
  30
  31     let monitor = Object()
  32
  33     let listeners = List<IListener>()
  34
  35     let debug =
  36 #if DEBUG
  37         true
  38 #else
  39         false
  40 #endif
  41
  42     static let instance = new Log()
  43
  44     let setLogDirectory (dir: string) =
  45         lock monitor (fun () ->
  46             logDir <- dir
  47             absoluteDir <- Path.Combine(System.Environment.GetFolderPath(Environment.SpecialFolder.ApplicationData), logDir)
  48
  49             if stream <> null
  50             then
  51                 stream.Close()
  52                 stream <- null
  53
  54             try
  55                 if not <| Directory.Exists(absoluteDir)
  56                 then
  57                     Directory.CreateDirectory(absoluteDir) |> ignore
  58             with
  59             | _ as ex -> Console.Error.WriteLine("Unable to create the log directory: {0}", absoluteDir))
  60
  61     let openLogFile () =
  62         try
  63             if stream = null || (nbEntries % (int64 nbEntriesCheckSize) = 0L) && stream.BaseStream.Length > maxSizeFile
  64             then
  65                 if stream <> null
  66                 then
  67                     stream.Close()
  68
  69                 let mutable n = 1
  70                 for existingFile in Directory.GetFiles(absoluteDir) do
  71                     let current_n = ref 0
  72                     if Int32.TryParse(existingFile.Remove(existingFile.LastIndexOf('.')), current_n) && !current_n > n
  73                     then
  74                         n <- !current_n
  75
  76                 let mutable filename = Path.Combine(absoluteDir, String.Format(filenameFormat, n))
  77                 try
  78                     if (FileInfo(filename).Length > maxSizeFile)
  79                     then
  80                         filename <- Path.Combine(absoluteDir, String.Format(filenameFormat, n + 1))
  81                 with
  82                 | :? FileNotFoundException -> () // The file may not exist.
  83
  84                 stream <- new StreamWriter(filename, true, encoding)
  85         with
  86         | _ as ex -> Console.Error.WriteLine("Can't open the file log: {0}", ex)
  87
  88     do
  89         setLogDirectory LogDefaultDirectory
  90
  91     interface IDisposable with
  92         member this.Dispose () =
  93             if stream <> null
  94             then
  95                 stream.Dispose()
  96
  97     member private this.Write (message: string, severity: Severity) =
  98         lock monitor (fun () ->
  99             nbEntries <- nbEntries + 1L
 100             openLogFile ()
 101
 102             if stream <> null
 103             then
 104                 let mutable moduleNameCaller = moduleName
 105                 match StackTrace().GetFrames() |> Array.tryPick (fun frame -> let name = frame.GetMethod().Module.Name
 106                                                                               if name <> moduleName then Some name else None) with
 107                 | Some name -> moduleNameCaller <- name
 108                 | _ -> ()
 109
 110                 let threadName = Thread.CurrentThread.Name
 111
 112                 for listener in listeners do
 113                     listener.NewEntry severity message
 114
 115                 try
 116                     stream.WriteLine(
 117                         "{0:yyyy-MM-dd HH:mm:ss.fff} [{1}] {{{2}}} ({3}) : {4}",
 118                         TimeZone.CurrentTimeZone.ToLocalTime(DateTime.UtcNow),
 119                         severity.ToString(),
 120                         moduleNameCaller,
 121                         (if String.IsNullOrEmpty(threadName) then Thread.CurrentThread.ManagedThreadId.ToString() else String.Format("{0}-{1}", threadName, Thread.CurrentThread.ManagedThreadId)),
 122                         message
 123                     )
 124                     stream.Flush()
 125                 with
 126                 | :? IOException as ex -> Console.Error.WriteLine("Unable to write to the log file: {0}", ex))
 127
 128
 129     member private this.AddListener (listener: IListener) =
 130         lock monitor (fun () ->
 131             if not <| listeners.Contains(listener)
 132             then
 133                 listeners.Add(listener))
 134
 135     member private this.RmListener (listener: IListener) =
 136         lock monitor (fun () ->
 137             listeners.Remove(listener) |> ignore)
 138
 139     static member AddListener (listener: IListener) = instance.AddListener(listener)
 140     static member RmListener (listener: IListener) = instance.RmListener(listener)
 141
 142     static member LogWithTime (message: string, severity: Severity, f: unit -> 'a option, [<ParamArray>] args: Object[]) : 'a option =
 143         let sw = Stopwatch()
 144         sw.Start()
 145         let res = f ()
 146         sw.Stop()
 147         if res.IsSome
 148         then
 149             instance.Write(String.Format(message, args) + sprintf " (time: %d ms)" sw.ElapsedMilliseconds, severity)
 150         res
 151
 152     static member Debug (message: string, [<ParamArray>] args: Object[]) =
 153 #if DEBUG
 154         instance.Write(String.Format(message, args), Severity.DEBUG)
 155 #else
 156         ()
 157 #endif
 158
 159     static member User (message: string, [<ParamArray>] args: Object[]) =
 160         instance.Write(String.Format(message, args), Severity.USER)
 161
 162     static member Warning (message: string, [<ParamArray>] args: Object[]) =
 163         instance.Write(String.Format(message, args), Severity.WARNING)
 164
 165     static member Error (message: string, [<ParamArray>] args: Object[]) =
 166         instance.Write(String.Format(message, args), Severity.ERROR)
 167
 168     static member Fatal (message: string, [<ParamArray>] args: Object[]) =
 169         instance.Write(String.Format(message, args), Severity.FATAL)
 170