Trying to figure out LazDaemon but facing obstacles

[r.lukasiak]

Hi everyone!
I'm trying to create a daemon/service. I'm following this link https://wiki.freepascal.org/Daemons_and_Services#Daemons_have_no_Access_to_Network-_and_Cloud_Drives_.28Onedrive.2C_Dropbox.29.
First I went the OnlyCode way, I just copy-pasted the code and I ran into:

Code: Pascal  [Select][+][-]

1. function TDaemon1.Install: boolean;
2.  
3.   var
4.     FilePath: string;
5.  
6.   begin
7.     Result := False;
8.     {$IFDEF WINDOWS}
9.     Result := inherited Install;
10.     {$ELSE}
11.       {$IFDEF UNIX}
12.       FilePath := GetSystemdControlFilePath(Self.Definition.Name);
13.       LogToFile(Format('TDaemon1: installing control file: %s',[FilePath]));
14.       Result := CreateSystemdControlFile(self, FilePath);  // <----------------------- I'm getting an error here
15.       if not Result then
16.         LogToFile('TDaemon1: Error creating systemd control file: ' + FilePath);
17.       {$ENDIF}
18.     {$ENDIF}
19.     LogToFile(Format('TDaemon1: service %s installed: %s', [self.Definition.Name, BoolToStr(Result, 'ok', 'failure')]));
20.   end;
21.  

I get:

kdaemon.lpr(145,46) Error: Incompatible type for arg no. 1: Got "TDaemon1", expected "TDaemon"

I commented it out and I managed to run the daemon. As expected, running my app with -i failed (as it's commented out), -u was OK and -r ran as needed, I checked the given PID and it was really running.

The I took the other approach. I created a new project "Daemon (service) application". First I played with OnStart / OnStop events, adding some simple Writeln, I ran it and it worked, fired with -r gave expected output and the same when I killed the process.
But then I kept following the tutorial and added the DataModuleStart and DataModuleStops procedures, this resulted in:

kdaemonunit.pas(43,3) Error: Identifier not found "FDaemonWorkerThread"

and indeed, the tutorial doesn't mention any var, whatsoever so I peeked on the OnlyCode version and added some uses and declared FDaemonWorkerThread

It compiles but when I run it, I get

$ ./KDaemon -i
An unhandled exception occurred at $00000000004284F4:
EDaemon: Not changing daemon mapper class TKDaemonMapper with TTestDaemonMapper: Only 1 mapper allowed.
  $00000000004284F4
  $00000000004283D7
  $00000000004F2999  DAEMONMAPPERUNIT_$$_init$,  line 40 of daemonmapperunit.pas
  $00000000004174AC

I get the same either I use any parameter or not.

Complete code:

Code: Pascal  [Select][+][-]

1. unit KDaemonUnit;
2.  
3. {$mode objfpc}{$H+}
4.  
5. interface
6.  
7. uses
8.   Classes, SysUtils, DaemonApp, lazdaemonapp, daemonmapperunit, DaemonUnit,
9.   DaemonWorkerThread;
10.  
11. type
12.  
13.   { TKDaemon }
14.  
15.   TKDaemon = class(TDaemon)
16.     procedure DataModuleStart(Sender: TCustomDaemon; var OK: Boolean);
17.     procedure DataModuleStop(Sender: TCustomDaemon; var OK: Boolean);
18.   private
19.     FDaemonWorkerThread: TDaemonWorkerThread;
20.  
21.   public
22.  
23.   end;
24.  
25. var
26.   KDaemon: TKDaemon;
27.  
28. implementation
29.  
30. procedure RegisterDaemon;
31. begin
32.   RegisterDaemonClass(TKDaemon)
33. end;
34.  
35. {$R *.lfm}
36.  
37. { TKDaemon }
38.  
39. procedure TKDaemon.DataModuleStart(Sender: TCustomDaemon; var OK: Boolean);
40. begin
41.   Writeln(Format('Daemon received start signal, PID:%d', [GetProcessID]));
42.   // Create a suspended worker thread - see DaemonWorkerThread unit
43.   FDaemonWorkerThread := TDaemonWorkerThread.Create;
44.   // Parametrize it
45.   FDaemonWorkerThread.FreeOnTerminate := False;
46.   // Start the worker
47.   FDaemonWorkerThread.Start;
48.   OK := True;
49. end;
50.  
51. procedure TKDaemon.DataModuleStop(Sender: TCustomDaemon; var OK: Boolean);
52. begin
53.   Writeln('Daemon received stop signal');
54.   // stop and terminate the worker
55.   if assigned(FDaemonWorkerThread) then
56.   begin
57.     FDaemonWorkerThread.Terminate;
58.     // Wait for the thread to terminate.
59.     FDaemonWorkerThread.WaitFor;
60.     FreeAndNil(FDaemonWorkerThread);
61.   end;
62.   Writeln('Daemon stopped');
63.   OK := True;
64. end;
65.  
66.  
67. initialization
68.   RegisterDaemon;
69. end.
70.  

At this point I have absolutely no clue what I did wrong. Any hint?