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authorankitjavalkar2015-09-14 12:28:41 +0530
committerankitjavalkar2015-09-15 11:33:59 +0530
commit7a60f782995eed0352f3172f445bb35ae8ee6aa9 (patch)
tree91d6d12b0a494dd9777fd1120e92db5763bf009a /yaksh/code_server.py
parent32cde26f9807a29eb1fae0833e353212d43d7802 (diff)
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Remove testapp dir, remove reference to testapp in paths, files
Diffstat (limited to 'yaksh/code_server.py')
-rwxr-xr-xyaksh/code_server.py162
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diff --git a/yaksh/code_server.py b/yaksh/code_server.py
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+#!/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::
+
+ $ sudo ./code_server.py
+ # Runs servers based on settings.py:SERVER_PORTS one server per port given.
+
+or::
+
+ $ sudo ./code_server.py 8001 8002 8003 8004 8005
+ # Runs 5 servers on ports specified.
+
+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
+from SimpleXMLRPCServer import SimpleXMLRPCServer
+import pwd
+import os
+import stat
+from os.path import isdir, dirname, abspath, join, isfile
+import signal
+from multiprocessing import Process, Queue
+import subprocess
+import re
+import json
+# Local imports.
+from settings import SERVER_PORTS, SERVER_POOL_PORT
+from language_registry import set_registry, get_registry
+
+
+MY_DIR = abspath(dirname(__file__))
+
+
+# Private Protocol ##########
+def run_as_nobody():
+ """Runs the current process as nobody."""
+ # Set the effective uid and to that of nobody.
+ nobody = pwd.getpwnam('nobody')
+ os.setegid(nobody.pw_gid)
+ os.seteuid(nobody.pw_uid)
+
+
+###############################################################################
+# `CodeServer` class.
+###############################################################################
+class CodeServer(object):
+ """A code server that executes user submitted test code, tests it and
+ reports if the code was correct or not.
+ """
+ def __init__(self, port, queue):
+ self.port = port
+ self.queue = queue
+
+ # Public Protocol ##########
+ def check_code(self, language, json_data, in_dir=None):
+ """Calls relevant EvaluateCode class based on language to check the
+ answer code
+ """
+ code_evaluator = self._create_evaluator_instance(language, json_data,
+ in_dir)
+ result = code_evaluator.evaluate()
+
+ # Put us back into the server pool queue since we are free now.
+ self.queue.put(self.port)
+
+ return json.dumps(result)
+
+ def run(self):
+ """Run XMLRPC server, serving our methods."""
+ server = SimpleXMLRPCServer(("localhost", self.port))
+ self.server = server
+ server.register_instance(self)
+ self.queue.put(self.port)
+ server.serve_forever()
+
+ # Private Protocol ##########
+ def _create_evaluator_instance(self, language, json_data, in_dir):
+ """Create instance of relevant EvaluateCode class based on language"""
+ set_registry()
+ registry = get_registry()
+ cls = registry.get_class(language)
+ instance = cls.from_json(language, json_data, in_dir)
+ return instance
+
+
+###############################################################################
+# `ServerPool` class.
+###############################################################################
+class ServerPool(object):
+ """Manages a pool of CodeServer objects."""
+ def __init__(self, ports, pool_port=50000):
+ """Create a pool of servers. Uses a shared Queue to get available
+ servers.
+
+ Parameters
+ ----------
+
+ ports : list(int)
+ List of ports at which the CodeServer's should run.
+
+ pool_port : int
+ Port at which the server pool should serve.
+ """
+ self.my_port = pool_port
+ self.ports = ports
+ queue = Queue(maxsize=len(ports))
+ self.queue = queue
+ servers = []
+ for port in ports:
+ server = CodeServer(port, queue)
+ servers.append(server)
+ p = Process(target=server.run)
+ p.start()
+ self.servers = servers
+
+ # Public Protocol ##########
+
+ def get_server_port(self):
+ """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
+
+ def run(self):
+ """Run server which returns an available server port where code
+ can be executed.
+ """
+ server = SimpleXMLRPCServer(("localhost", self.my_port))
+ self.server = server
+ server.register_instance(self)
+ server.serve_forever()
+
+
+###############################################################################
+def main(args=None):
+ run_as_nobody()
+ if args:
+ ports = [int(x) for x in args[1:]]
+ else:
+ ports = SERVER_PORTS
+
+ server_pool = ServerPool(ports=ports, pool_port=SERVER_POOL_PORT)
+ server_pool.run()
+
+if __name__ == '__main__':
+ args = sys.argv[1:]
+ main(args)