Last fixes; concurrency test for the server

3 files changed, 55 insertions, 6 deletions

diff --git a/project2/proj2_s4498062/dns/cache.py b/project2/proj2_s4498062/dns/cache.py
index a8b62be..9e3a508 100644
--- a/project2/proj2_s4498062/dns/cache.py
+++ b/project2/proj2_s4498062/dns/cache.py
@@ -20,7 +20,7 @@ class ResourceEncoder(json.JSONEncoder):
     Usage:
         string = json.dumps(records, cls=ResourceEncoder, indent=4)
     """
-    def default(self, obj):
+    def default(self, obj):  # pylint: disable=method-hidden
         if isinstance(obj, ResourceRecord):
             return {
                 "name":       obj.name,
@@ -90,6 +90,7 @@ class RecordCache(object):
             if r.match(name=dname, type_=type_, class_=class_)]
 
     def add_records_from(self, msg):
+        """Apply add_record to answers, authorities and additionals of msg"""
         for record in msg.answers + msg.authorities + msg.additionals:
             if record.type_ in [Type.A, Type.AAAA, Type.CNAME, Type.NS] and \
                     record.class_ == Class.IN:
diff --git a/project2/proj2_s4498062/dns/server.py b/project2/proj2_s4498062/dns/server.py
index 10cad8b..f1d33c1 100644
--- a/project2/proj2_s4498062/dns/server.py
+++ b/project2/proj2_s4498062/dns/server.py
@@ -19,7 +19,7 @@ from dns.resource import \
 class RequestHandler(Thread):
     """ A handler for requests to the DNS server """
 
-    def __init__(self, skt, ttl, data, addr, zone):
+    def __init__(self, skt, ttl, data, addr, zone, resolv):
         # pylint: disable=too-many-arguments
         """ Initialize the handler thread """
         super(RequestHandler, self).__init__()
@@ -29,11 +29,10 @@ class RequestHandler(Thread):
         self.data = data
         self.addr = addr
         self.zone = zone
+        self.resolv = resolv
 
     def run(self):
         """ Run the handler thread """
-        resolver = Resolver(True, self.ttl)
-
         request = Message.from_bytes(self.data)
         answs, adds, auths = [], [], []
 
@@ -44,7 +43,7 @@ class RequestHandler(Thread):
             if rrs != []:
                 auths += rrs
             elif req.qtype in [Type.A, Type.CNAME] and req.qclass == Class.IN:
-                name, cnames, addrs = resolver.gethostbyname(req.qname)
+                name, cnames, addrs = self.resolv.gethostbyname(req.qname)
                 if name != req.qname:
                     answs.append(ResourceRecord(
                         str(req.qname), Type.CNAME, Class.IN, self.ttl,
@@ -86,6 +85,7 @@ class Server(object):
         self.port = port
         self.done = False
         self.zone = []
+        self.resolv = Resolver(True, self.ttl)
 
         self.skt = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
 
@@ -95,7 +95,7 @@ class Server(object):
         while not self.done:
             data, addr = self.skt.recvfrom(512)
             reqh = RequestHandler(
-                self.skt, self.ttl, data, addr, zone=self.zone)
+                self.skt, self.ttl, data, addr, self.zone, self.resolv)
             reqh.start()
 
     def shutdown(self):
diff --git a/project2/proj2_s4498062/dns_tests.py b/project2/proj2_s4498062/dns_tests.py
index 6a5a16e..fe4ffc2 100755
--- a/project2/proj2_s4498062/dns_tests.py
+++ b/project2/proj2_s4498062/dns_tests.py
@@ -3,6 +3,7 @@
 
 # pylint: disable=too-many-public-methods, invalid-name
 
+import copy
 from random import randint
 import socket
 import sys
@@ -143,6 +144,53 @@ class TestServer(unittest.TestCase):
                 elif record.type_ == Type.CNAME:
                     self.assertIn(record.rdata.data, aliases)
 
+    def test_concurrency(self):
+        """Test the server's concurrent abilities
+
+        Note: we can never be sure that the server handles these requests in
+        parallel. What we do is (1) sending a request for a domain outside the
+        zone, and (2) sending a request for inside the zone. We would expect
+        the latter to be quicker.
+        """
+        sock = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
+        sock.settimeout(self.TIMEOUT)
+
+        header = Header(0, 0, 1, 0, 0, 0)
+        header.qr = 0
+        header.opcode = 0
+        header.rd = 1
+
+        header.ident = 1
+        req1 = Message(header, [Question('camilstaps.nl', Type.A, Class.IN)])
+
+        header = copy.copy(header)
+        header.ident = 2
+        req2 = Message(header, [Question('cloogle.org', Type.A, Class.IN)])
+
+        sock.sendto(req1.to_bytes(), ('127.0.0.1', portnr))
+        sock.sendto(req2.to_bytes(), ('127.0.0.1', portnr))
+
+        try:
+            # The second request
+            data = sock.recv(512)
+            resp = Message.from_bytes(data)
+            self.assertEqual(resp.header.ident, 2)
+            self.assert_match(
+                resp.authorities[0],
+                'cloogle.org', Type.A, Class.IN, '84.22.111.158')
+            self.assertEqual(resp.answers + resp.additionals, [])
+
+            # The first request
+            data = sock.recv(512)
+            resp = Message.from_bytes(data)
+            self.assertEqual(resp.header.ident, 1)
+            self.assert_match(
+                resp.answers[0],
+                'camilstaps.nl', Type.A, Class.IN, '84.22.111.158')
+            self.assertEqual(resp.authorities + resp.additionals, [])
+        except socket.timeout:
+            self.fail('timeout')
+
 if __name__ == "__main__":
     # Parse command line arguments
     import argparse