1 files changed, 88 insertions, 30 deletions

diff --git a/yaksh/code_server.py b/yaksh/code_server.py
index 2d8567e..e19e9c8 100755
--- a/yaksh/code_server.py
+++ b/yaksh/code_server.py
@@ -1,9 +1,11 @@
 #!/usr/bin/env python
-"""This server runs an XMLRPC server that can be submitted code and tests
-and returns the output.  It *should* be run as root and will run as the user
-'nobody' so as to minimize any damange by errant code.  This can be configured
-by editing settings.py to run as many servers as desired.  One can also
-specify the ports on the command line.  Here are examples::
+
+"""This server runs an HTTP server (using tornado) and several code servers
+using XMLRPC that can be submitted code
+and tests and returns the output.  It *should* be run as root and will run as
+the user 'nobody' so as to minimize any damange by errant code.  This can be
+configured by editing settings.py to run as many servers as desired.  One can
+also specify the ports on the command line.  Here are examples::
 
   $ sudo ./code_server.py
   # Runs servers based on settings.py:SERVER_PORTS one server per port given.
@@ -17,18 +19,32 @@ All these servers should be running as nobody.  This will also start a server
 pool that defaults to port 50000 and is configurable in
 settings.py:SERVER_POOL_PORT.  This port exposes a `get_server_port` function
 that returns an available server.
+
 """
-import sys
+
+# Standard library imports
 from SimpleXMLRPCServer import SimpleXMLRPCServer
-import pwd
+import json
+from multiprocessing import Process, Queue
 import os
-import stat
 from os.path import isdir, dirname, abspath, join, isfile
+import pwd
+import re
 import signal
-from multiprocessing import Process, Queue
+import stat
 import subprocess
-import re
-import json
+import sys
+
+try:
+    from urllib import unquote
+except ImportError:
+    # The above import will not work on Python-3.x.
+    from urllib.parse import unquote
+
+# Library imports
+from tornado.ioloop import IOLoop
+from tornado.web import Application, RequestHandler
+
 # Local imports.
 from settings import SERVER_PORTS, SERVER_POOL_PORT
 from language_registry import create_evaluator_instance, unpack_json
@@ -62,7 +78,7 @@ class CodeServer(object):
         """Calls relevant EvaluateCode class based on language to check the
          answer code
         """
-        code_evaluator = create_evaluator_instance(language, 
+        code_evaluator = create_evaluator_instance(language,
             test_case_type,
             json_data,
             in_dir
@@ -104,15 +120,30 @@ class ServerPool(object):
         """
         self.my_port = pool_port
         self.ports = ports
-        queue = Queue(maxsize=len(ports))
+        queue = Queue(maxsize=len(self.ports))
         self.queue = queue
         servers = []
-        for port in ports:
+        processes = []
+        for port in self.ports:
             server = CodeServer(port, queue)
             servers.append(server)
             p = Process(target=server.run)
-            p.start()
+            processes.append(p)
         self.servers = servers
+        self.processes = processes
+        self.app = self._make_app()
+
+    def _make_app(self):
+        app = Application([
+            (r"/.*", MainHandler, dict(server=self)),
+        ])
+        app.listen(self.my_port)
+        return app
+
+    def _start_code_servers(self):
+        for proc in self.processes:
+            if proc.pid is None:
+                proc.start()
 
     # Public Protocol ##########
 
@@ -120,36 +151,63 @@ class ServerPool(object):
         """Get available server port from ones in the pool.  This will block
         till it gets an available server.
         """
-        q = self.queue
-        was_waiting = True if q.empty() else False
-        port = q.get()
-        if was_waiting:
-            print '*'*80
-            print "No available servers, was waiting but got server \
-                   later at %d." % port
-            print '*'*80
-            sys.stdout.flush()
-        return port
+        return self.queue.get()
+
+    def get_status(self):
+        """Returns current queue size and total number of ports used."""
+        try:
+            qs = self.queue.qsize()
+        except NotImplementedError:
+            # May not work on OS X so we return a dummy.
+            qs = len(self.ports)
+
+        return qs, len(self.ports)
 
     def run(self):
         """Run server which returns an available server port where code
         can be executed.
         """
-        server = SimpleXMLRPCServer(("0.0.0.0", self.my_port))
+        # We start the code servers here to ensure they are run as nobody.
+        self._start_code_servers()
+        IOLoop.current().start()
+
+    def stop(self):
+        """Stop all the code server processes.
+        """
+        for proc in self.processes:
+            proc.terminate()
+        IOLoop.current().stop()
+
+
+class MainHandler(RequestHandler):
+    def initialize(self, server):
         self.server = server
-        server.register_instance(self)
-        server.serve_forever()
+
+    def get(self):
+        path = self.request.path[1:]
+        if len(path) == 0:
+            port = self.server.get_server_port()
+            self.write(str(port))
+        elif path == "status":
+            q_size, total = self.server.get_status()
+            result = "%d servers out of %d are free.\n"%(q_size, total)
+            load = float(total - q_size)/total*100
+            result += "Load: %s%%\n"%load
+            self.write(result)
 
 
 ###############################################################################
 def main(args=None):
-    run_as_nobody()
     if args:
-        ports = [int(x) for x in args[1:]]
+        ports = [int(x) for x in args]
     else:
         ports = SERVER_PORTS
 
     server_pool = ServerPool(ports=ports, pool_port=SERVER_POOL_PORT)
+    # This is done *after* the server pool is created because when the tornado
+    # app calls listen(), it cannot be nobody.
+    run_as_nobody()
+
     server_pool.run()
 
 if __name__ == '__main__':