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(Environment.GetFolderPath(Environment.SpecialFolder.ApplicationData), logDir)
  48
  49             if stream <> null then
  50                 stream.Close()
  51                 stream <- null
  52
  53             try
  54                 if not <| Directory.Exists(absoluteDir) then
  55                     Directory.CreateDirectory(absoluteDir) |> ignore
  56             with
  57             | _ as ex -> Console.Error.WriteLine("Unable to create the log directory: {0}", absoluteDir))
  58
  59     let openLogFile () =
  60         try
  61             if stream = null || (nbEntries % (int64 nbEntriesCheckSize) = 0L) && stream.BaseStream.Length > maxSizeFile then
  62                 if stream <> null then
  63                     stream.Close()
  64
  65                 let mutable n = 1
  66                 for existingFile in Directory.GetFiles(absoluteDir) do
  67                     let current_n = ref 0
  68                     if Int32.TryParse(existingFile.Remove(existingFile.LastIndexOf('.')), current_n) && !current_n > n then
  69                         n <- !current_n
  70
  71                 let mutable filename = Path.Combine(absoluteDir, String.Format(filenameFormat, n))
  72                 try
  73                     if (FileInfo(filename).Length > maxSizeFile) then
  74                         filename <- Path.Combine(absoluteDir, String.Format(filenameFormat, n + 1))
  75                 with
  76                 | :? FileNotFoundException -> () // The file may not exist.
  77
  78                 stream <- new StreamWriter(filename, true, encoding)
  79         with
  80         | _ as ex -> Console.Error.WriteLine("Can't open the file log: {0}", ex)
  81
  82     do
  83         setLogDirectory LogDefaultDirectory
  84
  85     interface IDisposable with
  86         member this.Dispose () =
  87             if stream <> null then
  88                 stream.Dispose()
  89
  90     member private this.Write (message : string, severity : Severity) =
  91         lock monitor (fun () ->
  92             nbEntries <- nbEntries + 1L
  93             openLogFile ()
  94
  95             if stream <> null then
  96                 let mutable moduleNameCaller = moduleName
  97                 match StackTrace().GetFrames() |> Array.tryPick (fun frame -> let name = frame.GetMethod().Module.Name
  98                                                                               if name <> moduleName then Some name else None) with
  99                 | Some name -> moduleNameCaller <- name
 100                 | _ -> ()
 101
 102                 let threadName = Thread.CurrentThread.Name
 103
 104                 for listener in listeners do
 105                     listener.NewEntry severity message
 106
 107                 try
 108                     stream.WriteLine(
 109                         "{0:yyyy-MM-dd HH:mm:ss.fff} [{1}] {{{2}}} ({3}) : {4}",
 110                         TimeZone.CurrentTimeZone.ToLocalTime(DateTime.UtcNow),
 111                         severity.ToString(),
 112                         moduleNameCaller,
 113                         (if String.IsNullOrEmpty(threadName) then Thread.CurrentThread.ManagedThreadId.ToString() else String.Format("{0}-{1}", threadName, Thread.CurrentThread.ManagedThreadId)),
 114                         message
 115                     )
 116                     stream.Flush()
 117                 with
 118                 | :? IOException as ex -> Console.Error.WriteLine("Unable to write to the log file: {0}", ex))
 119
 120
 121     member private this.AddListener (listener : IListener) =
 122         lock monitor (fun () ->
 123             if not <| listeners.Contains(listener) then
 124                 listeners.Add(listener))
 125
 126     member private this.RmListener (listener : IListener) =
 127         lock monitor (fun () ->
 128             listeners.Remove(listener) |> ignore)
 129
 130     static member AddListener (listener : IListener) = instance.AddListener(listener)
 131     static member RmListener (listener : IListener) = instance.RmListener(listener)
 132
 133     static member LogWithTime (message : string, severity : Severity, f : unit -> 'a option, [<ParamArray>] args: Object[]) : 'a option =
 134         let sw = Stopwatch()
 135         sw.Start()
 136         let res = f ()
 137         sw.Stop()
 138         if res.IsSome then
 139             instance.Write(String.Format(message, args) + sprintf " (time: %d ms)" sw.ElapsedMilliseconds, severity)
 140         res
 141
 142     static member Debug (message : string, [<ParamArray>] args : Object[]) =
 143 #if DEBUG
 144         instance.Write(String.Format(message, args), Severity.DEBUG)
 145 #else
 146         ()
 147 #endif
 148
 149     static member User (message : string, [<ParamArray>] args : Object[]) =
 150         instance.Write(String.Format(message, args), Severity.USER)
 151
 152     static member Warning (message : string, [<ParamArray>] args : Object[]) =
 153         instance.Write(String.Format(message, args), Severity.WARNING)
 154
 155     static member Error (message : string, [<ParamArray>] args : Object[]) =
 156         instance.Write(String.Format(message, args), Severity.ERROR)
 157
 158     static member Fatal (message : string, [<ParamArray>] args : Object[]) =
 159         instance.Write(String.Format(message, args), Severity.FATAL)
 160