Multiple instances of the same service in Delphi

Question

I have have an old windows service made in delphi that now has to be installed multiple times in the same server, I am trying to change the code so I am able to change the service name as I am instaling the service but I cannot make it work.

I find some information here and some here about it, and after study the posts and make the necessary modifications I am able to install two services with different names, however the services does not start.

I post the class responsible to control the service below (inherited TService), I know is quite a bit of code but I would really appreciate any help.

procedure ServiceController(CtrlCode: DWord); stdcall;
begin
  tvdAvalancheDataCenterService.Controller(CtrlCode);
end;
function TtvdAvalancheDataCenterService.GetServiceController: TServiceController;
begin
  Result := ServiceController;
end;
procedure TtvdAvalancheDataCenterService.ServiceLoadInfo(Sender : TObject);
begin
  Name := ParamStr(2);
  DisplayName := ParamStr(3);
end;
procedure TtvdAvalancheDataCenterService.ServiceBeforeInstall(Sender: TService);
begin
  ServiceLoadInfo(Self);
end;
procedure TtvdAvalancheDataCenterService.ServiceCreate(Sender: TObject);
begin
  ServiceLoadInfo(Self);
end;
procedure TtvdAvalancheDataCenterService.ServiceStart(Sender: TService;
  var Started: Boolean);
begin
  FtvdTrayIcon := TtvdEnvoyTrayIcon.Create(Self);
  SetServiceDescription;
  FtvdDataCenter.tvdActive := true;
end;
procedure TtvdAvalancheDataCenterService.ServiceStop(Sender: TService;
  var Stopped: Boolean);
begin
  FreeAndNil(FtvdTrayIcon);
  FtvdDataCenter.tvdActive := False;
end;
procedure TtvdAvalancheDataCenterService.ServiceAfterInstall(Sender: TService);
begin
   SetServiceDescription;
end;
procedure TtvdAvalancheDataCenterService.SetServiceDescription;
var
  aReg: TRegistry;
begin
  if FDescriptionUpdated then
    Exit;
  aReg := TRegistry.Create(KEY_READ or KEY_WRITE);
  try
    aReg.RootKey := HKEY_LOCAL_MACHINE;
    if aReg.OpenKey(cnRegKey+ Name, true) then
    begin
      aReg.WriteString('Description', cnServiceDescription);
      aReg.CloseKey;
    end;
    FDescriptionUpdated:= True;
  finally
    aReg.Free;
  end;
end;

I am using Delphi XE and the service need to run in windows services.

Thanks in advance

Answer 1

Since the service does not know what name it has received on installation, you can supply that name as a parameter into it's ImagePath registry value.

here's a basic service skeleton for multiple instances:

unit u_svc_main;

interface

uses
  Winapi.Windows,
  System.Win.Registry,
  System.SysUtils,
  System.Classes,
  Vcl.Dialogs,
  Vcl.SvcMgr;

type
  TSvc_test = class(TService)
    procedure ServiceAfterInstall(Sender: TService);
    procedure ServiceBeforeInstall(Sender: TService);
    procedure ServiceCreate(Sender: TObject);
    procedure ServiceBeforeUninstall(Sender: TService);
  private
    { Private declarations }
    procedure GetServiceName;
    procedure GetServiceDisplayName;
  public
    function GetServiceController: TServiceController; override;
    { Public declarations }
  end;

var
  Svc_test: TSvc_test;

implementation

{$R *.dfm}
procedure TSvc_test.GetServiceDisplayName;

var
  ServiceDisplayName : String;

begin
 if not FindCmdLineSwitch('display', ServiceDisplayName) then
  raise Exception.Create('Please specify the service displayname with /display switch');
 DisplayName := ServiceDisplayName;
end;

procedure TSvc_test.GetServiceName;

var
  ServiceName : String;

begin
 if not FindCmdLineSwitch('name', ServiceName) then
  raise Exception.Create('Please specify the service name with /name switch');
 Name := ServiceName;
end;

procedure ServiceController(CtrlCode: DWord); stdcall;
begin
  Svc_test.Controller(CtrlCode);
end;

function TSvc_test.GetServiceController: TServiceController;
begin
  Result := ServiceController;
end;

procedure TSvc_test.ServiceAfterInstall(Sender: TService);

var
  Reg       : TRegistry;
  ImagePath : String;

begin
 Reg := TRegistry.Create(KEY_READ OR KEY_WRITE);
 try
  Reg.RootKey := HKEY_LOCAL_MACHINE;
  if Reg.OpenKey('SYSTEM\CurrentControlSet\Services\'+Name, False) then
   begin
    // set service description
    Reg.WriteString('Description', 'Multi instance test for service '+Name);
    // add name parameter to ImagePath value
    ImagePath := ParamStr(0) + ' /name '+Name;
    Reg.WriteString('ImagePath', ImagePath);
    Reg.CloseKey;
   end;
 finally
  Reg.Free;
 end;
end;

procedure TSvc_test.ServiceBeforeInstall(Sender: TService);
begin
 GetServiceName;
 GetServiceDisplayName;
end;

procedure TSvc_test.ServiceBeforeUninstall(Sender: TService);
begin
 GetServiceName;
end;

procedure TSvc_test.ServiceCreate(Sender: TObject);
begin
 if not Application.Installing then
  GetServiceName;
end;

end.

Service installation:

<path1>\MyService.Exe /install /name "test1" /display "test instance1"
<path2>\MyService.Exe /install /name "test2" /display "test instance2"

Service removal:

<path1>\MyService.Exe /uninstall /name "test1" 
<path2>\MyService.Exe /uninstall /name "test2" 

Answer 2

It's fairly simple. You just have to set the name different for each service.

You now have:

Name := ParamStr(2);

DisplayName := ParamStr(3);

and just have to change it to:

Name := baseServiceName + '-' + GetLastDirName;

DisplayName := baseServiceDisplayName + ' (' + GetLastDirName + ')';

where baseServiceName is a constant with the name of the service; baseServiceDisplayName is a constant with the display name and GetLastDirName is a function that returns the name of a directory (last directory) from ExtractFilePath(ParamStr(0))

```

function GetLastDirName: string;
var
  aux: string;
  p: Integer;
begin
  aux := strDelSlash(ExtractFilePath(ParamStr(0)));
  p := StrLastPos('\', aux);
  if p > 0 then
    result := Copy(aux, p + 1, Length(aux))
  else
    result := aux;
end;

```

strDelSlash deletes the last slash; StrLastPos searches for the last position of the slash