Add code to ENSURE plack gets properly killed.

frameworks/Perl/plack/setup.py

@@ -15,11 +15,29 @@ def start(args, logfile, errfile):
     return 0
   except subprocess.CalledProcessError:
     return 1
-def stop(logfile, errfile):
-  try:
-    subprocess.call('kill -TERM $(cat $TROOT/app.pid)', shell=True, stderr=errfile, stdout=logfile)
-    subprocess.call("sudo /usr/local/nginx/sbin/nginx -c $TROOT/nginx.conf -s stop", shell=True, stderr=errfile, stdout=logfile)
-    return 0
-  except subprocess.CalledProcessError:
-    return 1
 
+ def stop(logfile, errfile):
+   try:
+     subprocess.Popen("kill -TERM $(ps --ppid `cat app.pid` -o pid --no-header)", shell=True, cwd="plack", stderr=errfile, stdout=logfile)
+     # TE - There was an issue on the EC2 machines where this, for reasons unknown,
+     # was not sufficient in cleanly ending plack. In fact, the above would not 
+     # successfully kill the starter process which would result in this 'stop' call
+     # to report success but leave port 8080 bound to a plackup instance. We tried
+     # adding a 'nuke' approach which detects the test's port still being bound
+     # after calling stop and then directly kills those pids a few times to try and
+     # cleanly release any/all ports (over 6000).
+     # Why this only happens on EC2 is just a guess, but somehow the server seems
+     # overwhelmed by the sheer volume of requests from the client and gets into
+     # a deadlock state. Calling "kill -15 [pid]" against the server process does
+     # nothing; so we needed a general way to kill all the processes that were 
+     # spawned by the original process. For plack, this was as simple as the next
+     # subprocess.Popen call (killall -s 9 plackup), but to do this generally is
+     # a bit more difficult.
+ 
+     # TE - In general, no test should ever be forced to use the KILL sigterm;
+     # TERM should be sufficient. However, in this case it seems that the plack
+     # server gets into a deadlock state and will not respond to a TERM sigterm.
+     subprocess.Popen("killall -s 9 plackup")
+     return 0
+   except subprocess.CalledProcessError:
+     return 1