pAntler + GNU screen

[ianfixes]

Launch Processes in GNU Screen

This patch is a refactor of pAntler in order to add a new launch option: GNU screen (http://en.wikipedia.org/wiki/GNU_Screen).

The major benefit of launching screens is that unlike Newconsole = false (in which stdout/stderr text isn't visible) and Newconsole = true (in which the window with the program output is always visible), screen sessions provide a way to connect to a running process when needed, without putting xterms in your face.

Before

This is an example of a pAntler config block.

ProcessConfig = ANTLER
{
  Run = MOOSDB @ Newconsole=true, XConfig=blah ~ MOOSDB
  blah = -geometry,80x40+0+20
}

After

LaunchType replaces NewConsole (which is now the fallback option). LaunchType may be (case-insensitively) Process, Console, or Screen.

Here's the same block with the new configuration style.

ProcessConfig = ANTLER
{
  Run = MOOSDB @ LaunchType=Process, XConfig=blah ~ MOOSDB
  blah = -geometry,80x40+0+20
}

Better

Here's how to launch it in a screen. We're adding the ScreenConfig option -L which enables logging for the console output, but this is entirely unnecessary; it's here for demonstration.

ProcessConfig = ANTLER
{
  Run = MOOSDB @ LaunchType=Screen, ScreenConfig=blah ~ MOOSDB
  blah = -L
}

Running pAntler will launch this screen session. You can observe it by typing screen -ls in a terminal. You'll get something like the following:

$ screen -ls
There is a screen on:
    16833.MOOSDB    (10/28/2013 05:30:37 PM)    (Detached)
1 Socket in /var/run/screen/S-xxx.

And if you type screen -R MOOSDB, you can connect to it:

***************************************************
*       This is MOOS Server for Community "#1"
*       c. P Newman 2001
*
*       Binding on 9000
*
*       This machine is Little endian
***************************************************

------------CONNECT-------------
New client connected from machine "localhost"
Handshaking....done
clients name is "DBWebServer"
There are now 1 clients connected.
--------------------------------

*****************************************************
  serving webpages HTTP on http://xxxxx:9080
*****************************************************

Testing

A sample MOOS configuration file, test-antler-nix.moos, is provided to test each of the launch methods under *nix. Among various xmessage dialog boxes that will come up to indicate the launch parameters of each line, there will be a summary for the screen sessions that's displayed in an xterm. Output should be similar to the following:

There are screens on:
        8714.xmessage-newlaunch-screen  (11/01/2013 10:42:15 AM)        (Detached)
        8667.MOOSDB     (11/01/2013 10:42:09 AM)        (Detached)
2 Sockets in /var/run/screen/S-xxx.

This has been lightly tested in Ubuntu, but is untested in Win32. Presumed to work, because it's just using the old code in a new place. Please report back.

[tsaubergine]

I have done preliminary testing with this patch (on Ubuntu 12.04 LTS amd64) and this appears to be a useful feature.

-Toby

[tsaubergine]

I have found a bug with a previously working configuration file, that now breaks with this patch.

I have stripped out all the configuration except that line that makes it break. pAntler will launch "MOOSDB" and "uMS" with no parameters:

MOOSDB
uMS

whereas the expected behavior is to launch them with the typical MOOS parameters
MOOSDB last-small.moos MOOSDB
uMS last-small.moos uMS

last-small.moos:

ProcessConfig = pSomeApp
{
ADD_AUV=pose=[4x1]{100000,123000,-30,15},name = UNICORN,InputPrefix=,OutputPrefix=FRONTSEAT_
}

ProcessConfig = ANTLER
{
DebugLaunch = true
MSBetweenLaunches = 100
Run = MOOSDB @ NewConsole = false
Run = uMS @ NewConsole = false
}

[tsaubergine]

No, here's the initialization that was removed.

[ianfixes]

Does the problem still persist? Are there any other problems with this pull request?