Console application
lazarus / 32-Linux

----------------------------------------------------------------------
ertank · 2018-01-19 23:35

Hello,

I am using Lazarus 1.8.1 (fixes_1_8 branch) and fpc 3.1.1 (trunk).
Both built from scratch. My system is a Debian 9. Lazarus and fpc last
check out was 3 days ago. OS updated & upgraded 3 days ago, too.

I am trying to build myself a kind of server. I use database access
(Zeoslib), http (IdHTTPServer), tcp (IdTCPServer), some routines from
mORMot framework. All of these are put in a TDataModule as well as all
my logic code.

I have enabled threading using -dUseCThreads in custom project
options.

My project has only following code:
Code: [Select]program httpserver_tcpserver;

{$mode objfpc}{$H+}

uses
  {$IFDEF UNIX}{$IFDEF UseCThreads}
  cthreads,
  {$ENDIF}{$ENDIF}
  Interfaces,
  SysUtils,
  uData,
  zcomponent,
  indylaz;

begin
  try
    DM := TDM.Create(nil);
    try
      if not DM.IdTCPServer1.Active then Exit();
      if not DM.IdHTTPServer1.Active then Exit();

      if not DM.DB.Connected then
      begin
        DM.Log('No database connection. Exiting...');
        Exit();
      end;

      while True do Sleep(250);
    finally
      DM.Log('server stopped.');
      DM.Free();
    end;
  except
    on E: Exception do
    begin
      WriteLn('error: ' + E.Message);
    end;
  end;
end.
uData is not included in application using project manager, but
included as a unit.

When I try to run compiled application in console, I get following
warnings (I tried to translate them to English as Linux locale is not
English. They should be something similar):
Code: [Select](project1:2076): Gtk-WARNING **: Theme device
module_path could not be found in "adwaita",
(project1:2076): Gtk-WARNING **: Theme device module_path could not be
found in "adwaita",
What I would like is a pure console application and no GUI. I am not
bothered with warnings normally, but I cannot start my application at
boot time using /etc/rc.local. What I observe is that it cannot become
a daemon but sticks to a TTY. I believe that behavior prevents it to
auto-run at system reboot. I can manually run it if a user login and
run the executable. Executable do not require root access rights, and
can runs as a regular user.

if I remove LCL, FCL dependency from project manager, also remove
Interfaces unit from uses and compile. I get linking errors at my very
final "end." line above. Says "generic error while linking". (Yes, I
received that warning dialog displayed at me about removing LCL will
result funny errors).

I started a new project using Project->New Project->Program which is
indicated as command line program. Added uData to my uses and I
continue to get these warnings above. Exactly same error if I do not
include Intercafes unit, let LCL stay as a dependency in project
manager.

Things do not change if I set my widget to "nogui".

I am stuck and any help is appreciated.

----------------------------------------------------------------------
Lutz Mändle · 2018-01-20 00:33

Set the widgetsettype to nogui and compile with cleanup and build. The
widgetsettype selects the version of the interfaces unit.

----------------------------------------------------------------------
ertank · 2018-01-20 14:12

I converted my application to use LazDaemon and to become a daemon.
However, It hangs on the console when I run it.

Attached project is re-producing my problem.

Basically, I am looping in Execute event as following:
Code: [Select]procedure TDaemon1.DataModuleExecute(Sender:
TCustomDaemon);
begin
  Log('executing...');

  while Self.Status = csRunning do
  begin
    Sleep(1000);
  end;
end;

When I run daemontest in shell I get following behavior:
Code: [Select]ek@debian:~/daemontest$ ./daemontest -r
^Cek@debian:~/daemontest$ cat daemontest.log
2018-01-20 17:06:12.348   daemontest started
2018-01-20 17:06:12.348   executing...
ek@debian:~/daemontest$
Which means, my daemon cannot go in background by itself as regular
linux daemons do. (Pay attention to "^C" in above screen output)

I appreciate any help on modifying my code so that it does behave like
a real daemon under linux OS.

Thanks & regards.

----------------------------------------------------------------------
Lutz Mändle · 2018-01-21 14:32

The daemon needs the commandline option -b to go in the background by
itself. This is the designed behavior of FPCs daemonapp framework.
Look in ....../packages/fcl-extra/src/unix/daemonapp.inc.
Be aware that by self backgrounding the daemon changes it's working
directory to '/' so that your Log procedure probably don't work. Use
an absolute path for the logfile which points to a location where the
daemon can write.

----------------------------------------------------------------------
ertank · 2018-01-21 15:24

I see following options printed on the screen if I execute the
application without any parameter
Code: [Select]Where command is one of the following:
  -i --install   To install the program as a service
  -u --uninstall To uninstall the service
  -r --run       To run the service

Same display printed if I execute the application with "-d" or "-b"
parameter.

----------------------------------------------------------------------
Lutz Mändle · 2018-01-21 15:46

The shown output is valid for windows because on that os this is the
established behaviour. But installing or uninstalling does not work
that way in linux. The relevant methods for installing and
uninstalling in daemonapp.inc for unix are empty.

On unix/linux the only working option from the help message is
-r/--run and the option -b/--background is not mentioned, execute the
application with "-r" and "-b" parameter.

----------------------------------------------------------------------
ertank · 2018-01-21 18:07

Using "-r" and "-b" together did put the application in background. I
still shall do more tests. However, I now hope that it will be fine
for my needs.

Thank you.