Debug mode now has an off mode to silence tracebacks on 500, per redbo's suggestion.

eventlet/wsgi.py

@@ -359,13 +359,16 @@ class HttpProtocol(BaseHTTPServer.BaseHTTPRequestHandler):
                     write('')
             except Exception:
                 self.close_connection = 1
-                exc = traceback.format_exc()
-                self.server.log_message(exc)
+                tb = traceback.format_exc()
+                self.server.log_message(tb)
                 if not headers_set:
+                    err_body = ""
+                    if(self.server.debug):
+                        err_body = tb
                     start_response("500 Internal Server Error",
                                    [('Content-type', 'text/plain'),
-                                    ('Content-length', len(exc))])
-                    write(exc)
+                                    ('Content-length', len(err_body))])
+                    write(err_body)
         finally:
             if hasattr(result, 'close'):
                 result.close()
@@ -455,6 +458,7 @@ class HttpProtocol(BaseHTTPServer.BaseHTTPRequestHandler):
         self.connection.close()
 
 
+
 class Server(BaseHTTPServer.HTTPServer):
     def __init__(self,
                  socket,
@@ -467,7 +471,8 @@ class Server(BaseHTTPServer.HTTPServer):
                  minimum_chunk_size=None,
                  log_x_forwarded_for=True,
                  keepalive=True,
-                 log_format=DEFAULT_LOG_FORMAT):
+                 log_format=DEFAULT_LOG_FORMAT,
+                 debug=True):
 
         self.outstanding_requests = 0
         self.socket = socket
@@ -486,6 +491,7 @@ class Server(BaseHTTPServer.HTTPServer):
             protocol.minimum_chunk_size = minimum_chunk_size
         self.log_x_forwarded_for = log_x_forwarded_for
         self.log_format = log_format
+        self.debug = debug
 
     def get_environ(self):
         d = {
@@ -531,7 +537,8 @@ def server(sock, site,
            log_x_forwarded_for=True,
            custom_pool=None,
            keepalive=True,
-           log_format=DEFAULT_LOG_FORMAT):
+           log_format=DEFAULT_LOG_FORMAT,
+           debug=True):
     """  Start up a wsgi server handling requests from the supplied server
     socket.  This function loops forever.  The *sock* object will be closed after server exits,
     but the underlying file descriptor will remain open, so if you have a dup() of *sock*,
@@ -550,6 +557,7 @@ def server(sock, site,
     :param custom_pool: A custom GreenPool instance which is used to spawn client green threads.  If this is supplied, max_size is ignored.
     :param keepalive: If set to False, disables keepalives on the server; all connections will be closed after serving one request.
     :param log_format: A python format string that is used as the template to generate log lines.  The following values can be formatted into it: client_ip, date_time, request_line, status_code, body_length, wall_seconds.  The default is a good example of how to use it.
+    :param debug: True if the server should send exception tracebacks to the clients on 500 errors.  If False, the server will respond with empty bodies.
     """
     serv = Server(sock, sock.getsockname(),
                   site, log,
@@ -559,7 +567,8 @@ def server(sock, site,
                   minimum_chunk_size=minimum_chunk_size,
                   log_x_forwarded_for=log_x_forwarded_for,
                   keepalive=keepalive,
-                  log_format=log_format)
+                  log_format=log_format,
+                  debug=debug)
     if server_event is not None:
         server_event.send(serv)
     if max_size is None:

tests/wsgi_test.py

@@ -124,7 +124,7 @@ def read_http(sock):
             raise ConnectionClosed
         raise
     if not response_line:
-        raise ConnectionClosed
+        raise ConnectionClosed(response_line)
     
     header_lines = []
     while True:
@@ -174,7 +174,6 @@ class _TestBase(LimitedTestCase):
         eventlet.sleep(0) # give previous server a chance to start
         if self.killer:
             greenthread.kill(self.killer)
-            eventlet.sleep(0) # give killer a chance to kill
 
         new_kwargs = dict(max_size=128,
                           log=self.logfile,
@@ -952,6 +951,58 @@ class TestHttpd(_TestBase):
         self.assertEqual(headers['connection'], 'close')
         self.assert_('unicode' in body)
 
+    def test_ipv6(self):
+        try:
+            sock = eventlet.listen(('::1', 0), family=socket.AF_INET6)
+        except (socket.gaierror, socket.error):  # probably no ipv6
+            return
+        log = StringIO()
+        # first thing the server does is try to log the IP it's bound to
+        def run_server():
+            try:
+                server = wsgi.server(sock=sock, log=log, site=Site())
+            except ValueError:
+                log.write('broked')
+        eventlet.spawn_n(run_server)
+        logval = log.getvalue()
+        while not logval:
+            eventlet.sleep(0.0)
+            logval = log.getvalue()
+        if 'broked' in logval:
+            self.fail('WSGI server raised exception with ipv6 socket')
+
+    def test_debug(self):
+        self.spawn_server(debug=False)
+        def crasher(env, start_response):
+            raise RuntimeError("intentional crash")
+        self.site.application = crasher
+
+        sock = eventlet.connect(('localhost', self.port))
+        fd = sock.makefile('w')
+        fd.write('GET / HTTP/1.1\r\nHost: localhost\r\n\r\n')
+        fd.flush()
+        response_line, headers, body = read_http(sock)
+        self.assert_(response_line.startswith('HTTP/1.1 500 Internal Server Error'))
+        self.assertEqual(body, '')
+        self.assertEqual(headers['connection'], 'close')
+        self.assert_('transfer-encoding' not in headers)
+
+        # verify traceback when debugging enabled
+        self.spawn_server(debug=True)
+        self.site.application = crasher
+        sock = eventlet.connect(('localhost', self.port))
+        fd = sock.makefile('w')
+        fd.write('GET / HTTP/1.1\r\nHost: localhost\r\n\r\n')
+        fd.flush()
+        response_line, headers, body = read_http(sock)
+        self.assert_(response_line.startswith('HTTP/1.1 500 Internal Server Error'))
+        self.assert_('intentional crash' in body)
+        self.assert_('RuntimeError' in body)
+        self.assert_('Traceback' in body)
+        self.assertEqual(headers['connection'], 'close')
+        self.assert_('transfer-encoding' not in headers)
+
+
 def read_headers(sock):
     fd = sock.makefile()
     try:
@@ -1136,27 +1187,7 @@ class TestChunkedInput(_TestBase):
             signal.alarm(0)
             signal.signal(signal.SIGALRM, signal.SIG_DFL)
 
-        assert not got_signal, "caught alarm signal. infinite loop detected."
-
-    def test_ipv6(self):
-        try:
-            sock = eventlet.listen(('::1', 0), family=socket.AF_INET6)
-        except (socket.gaierror, socket.error):  # probably no ipv6
-            return
-        log = StringIO()
-        # first thing the server does is try to log the IP it's bound to
-        def run_server():
-            try:
-                server = wsgi.server(sock=sock, log=log, site=Site())
-            except ValueError:
-                log.write('broked')
-        eventlet.spawn_n(run_server)
-        logval = log.getvalue()
-        while not logval:
-            eventlet.sleep(0.0)
-            logval = log.getvalue()
-        if 'broked' in logval:
-            self.fail('WSGI server raised exception with ipv6 socket')
+        assert not got_signal, "caught alarm signal. infinite loop detected."        
 
 
 if __name__ == '__main__':