[PATCH] fix for process spawning

[John Brush <jo...@ideartis.ch>]

I am using Ant to do some development with weblogic server, and I ran into
some problems trying to get it to return after spawning a new process/window
at the command line (Windows 2000). A quick scan of this mail list showed me
I was not the first person to run into this problem. Unfortunatly I don't
have the time to research this in more detail (got a deadline end of Feb.),
but the attached patch has at least solved my problem. Perhaps it can serve
as a basis for something along these lines in a future release.

Here's what my target now looks like, with the addition of the
"waitforcompletion" attribute:

  <target name="wl.start" depends="wl.deploy">
    <exec executable="c:\winnt\system32\cmd.exe"
          failonerror="yes"
          waitforcompletion="no">
      <arg line="/c start cmd /c &quot;cd ${weblogic} &amp; startweblogic
&quot;"/>
    </exec>
  </target>

John

--- C:\ant-src2\src\main\org\apache\tools\ant\taskdefs\ExecTask.java	Tue Oct
24 07:45:26 2000
+++ ExecTask.java	Wed Feb 07 11:04:10 2001
@@ -74,6 +74,7 @@
     private File out;
     private File dir;
     protected boolean failOnError = false;
+    private boolean waitforcompletion = true;
     private Integer timeout = null;
     private Environment env = new Environment();
     protected Commandline cmdl = new Commandline();
@@ -132,6 +133,13 @@
     }

     /**
+     * Allow process spawning
+     */
+    public void setWaitforcompletion(boolean wait) {
+        waitforcompletion = wait;
+    }
+
+    /**
      * Add a nested env element - an environment variable.
      */
     public void addEnv(Environment.Variable var) {
@@ -191,6 +199,7 @@
         Execute exe = new Execute(createHandler(), createWatchdog());
         exe.setAntRun(project);
         exe.setWorkingDirectory(dir);
+        exe.setWaitforcompletion(waitforcompletion);
         String[] environment = env.getVariables();
         if (environment != null) {
             for (int i=0; i<environment.length; i++) {
--- C:\ant-src2\src\main\org\apache\tools\ant\taskdefs\Execute.java	Tue Oct
24 07:45:26 2000
+++ Execute.java	Wed Feb 07 13:36:54 2001
@@ -84,6 +84,7 @@
     private ExecuteWatchdog watchdog;
     private File workingDirectory = null;
     private Project project = null;
+    private boolean waitforcompletion = true;

     private static String antWorkingDirectory =
System.getProperty("user.dir");
     private static CommandLauncher launcher = createCommandLauncher();
@@ -170,6 +171,9 @@
         this.watchdog = watchdog;
     }

+    public void setWaitforcompletion(boolean wait) {
+        waitforcompletion = wait;
+    }

     /**
      * Returns the commandline used to create a subprocess.
@@ -245,6 +249,12 @@
      */
     public int execute() throws IOException {
         final Process process = launcher.exec(project, getCommandline(),
getEnvironment(), workingDirectory);
+
+        // If the user is spawning a seperate process --> don't try to
redirect the streams
+        // and don't wait for the exit status
+        if ( !waitforcompletion )
+            return 0;
+
         try {
             streamHandler.setProcessInputStream(process.getOutputStream());
             streamHandler.setProcessOutputStream(process.getInputStream());



--------------------------------------------------------
John Brush, Ideartis Consulting
Mobile 079 235 17 56, tel 01 420 16 94, fax 01 420 16 93
Post: Horneggstr. 9, CH-8008 Zürich
Office Technopark: Technoparkstrasse 1, CH-8005 Zürich
Email: john.brush@ideartis.ch, Internet: www.ideartis.ch
--------------------------------------------------------

Re: [PATCH] fix for process spawning

[Bill Burton <bi...@progress.com>]

Hello,

A number of people have asked for this kind of detached or background
starting of an executable.  I wrote generic support for this but didn't
have it sufficiently tested before code freeze hit for the 1.3 release.

What I've implemented allows the <exec> task (and it's subclasses) to run
an executable detached in the background either redirecting the output to
a file or opening a new window.  This is done in a platform-independent
manner (at least for Windows 9x/NT/2K and UNIX).  The <exec> task supports
four new attributes and one modified one:

    detach=true|false - if true, runs process detached in the background
    output=file-name - modified so this works when detach=true
    inwindow=true|false - if true, runs process detached in a new window.
        On Windows OS's opens a new console window.  On UNIX, can run
xterm, 
        CDE dtterm, KDE konsole or gnome-terminal (and I plan to add
screen).
        The type of window and geometry can be selected by exporting 
        environment variables before running Ant.
    windowtitle="title of new window" - Title to display in new window
when
        the inwindow attribute is set to true.
    usescript=true|false - When true, will always use the script launcher 
        causing the antRun script to be called to execute the command.
This
        works even if Ant is running in a 1.3 JVM.

Something I may consider is writing new versions of Execute.runCommand
that will support detached with output or detached in a window.  This will
make it easier for other tasks to use this functionality.

As some of my changes conflict with at least one recently posted patch,
I'll post a patch once things settle down with the 1.3 release.  In the
meantime, if anyone has comments on this functionality, I'm open to any
input.

-Bill Burton

John Brush wrote:
> 
> I am using Ant to do some development with weblogic server, and I ran into
> some problems trying to get it to return after spawning a new process/window
> at the command line (Windows 2000). A quick scan of this mail list showed me
> I was not the first person to run into this problem. Unfortunatly I don't
> have the time to research this in more detail (got a deadline end of Feb.),
> but the attached patch has at least solved my problem. Perhaps it can serve
> as a basis for something along these lines in a future release.

<snip/>