caddy-frontend: Make test server serving in threads

Since haproxy checks the test server for availability and does it
asynchronously, the test server has to reply ASAP for given request, but when
one request blocks, then whole server is blocked, so just simply switch it to
threading model.

It's not the best, but good enough for test usage.

software/caddy-frontend/test/test.py

@@ -37,6 +37,7 @@ from unittest import skip
 import ssl
 from BaseHTTPServer import HTTPServer
 from BaseHTTPServer import BaseHTTPRequestHandler
+from SocketServer import ThreadingMixIn
 import time
 import tempfile
 import ipaddress
@@ -198,6 +199,10 @@ def createCSR(common_name, ip=None):
   return key, key_pem, csr, csr_pem
 
 
+class ThreadedHTTPServer(ThreadingMixIn, HTTPServer):
+  pass
+
+
 class CertificateAuthority(object):
   def __init__(self, common_name):
     self.key, self.key_pem = createKey()
@@ -599,11 +604,11 @@ class HttpFrontendTestCase(SlapOSInstanceTestCase):
 
   @classmethod
   def startServerProcess(cls):
-    server = HTTPServer(
+    server = ThreadedHTTPServer(
       (cls._ipv4_address, cls._server_http_port),
       TestHandler)
 
-    server_https = HTTPServer(
+    server_https = ThreadedHTTPServer(
       (cls._ipv4_address, cls._server_https_port),
       TestHandler)
 
@@ -655,7 +660,7 @@ class HttpFrontendTestCase(SlapOSInstanceTestCase):
     class OwnTestHandler(TestHandler):
       identification = 'Auth Backend'
 
-    server_https_auth = HTTPServer(
+    server_https_auth = ThreadedHTTPServer(
       (self._ipv4_address, self._server_https_auth_port),
       OwnTestHandler)
 
@@ -7139,14 +7144,14 @@ backend _health-check-default-http
 
 
 if __name__ == '__main__':
-  class HTTP6Server(HTTPServer):
+  class HTTP6Server(ThreadedHTTPServer):
     address_family = socket.AF_INET6
   ip, port = sys.argv[1], int(sys.argv[2])
   if ':' in ip:
     klass = HTTP6Server
     url_template = 'http://[%s]:%s/'
   else:
-    klass = HTTPServer
+    klass = ThreadedHTTPServer
     url_template = 'http://%s:%s/'
 
   server = klass((ip, port), TestHandler)