Add config check before reload

Fix tests

Author: Mark van Rossum

haproxy/config.py

@@ -129,6 +129,7 @@ def parse_additional_backend_settings(envvars):
 CACERT_DIR = "/cacerts/"
 HAPROXY_CONFIG_FILE = "/haproxy.cfg"
 HAPROXY_RUN_COMMAND = ['/usr/sbin/haproxy', '-f', HAPROXY_CONFIG_FILE, '-db', '-q']
+HAPROXY_CONFIG_CHECK_COMMAND = ['/usr/sbin/haproxy', '-c', '-f', HAPROXY_CONFIG_FILE]
 API_RETRY = 10  # seconds
 PID_FILE = "/tmp/dockercloud-haproxy.pid"
 SERVICE_PORTS_ENVVAR_NAME = "SERVICE_PORTS"

haproxy/helper/update_helper.py

@@ -4,7 +4,7 @@
 import time
 import errno
 
-from haproxy.config import HAPROXY_RUN_COMMAND, RELOAD_TIMEOUT
+from haproxy.config import HAPROXY_RUN_COMMAND, RELOAD_TIMEOUT, HAPROXY_CONFIG_CHECK_COMMAND
 
 logger = logging.getLogger("haproxy")
 
@@ -22,6 +22,16 @@
 #
 def run_reload(old_process, timeout=int(RELOAD_TIMEOUT)):
     if old_process:
+        p = subprocess.Popen(HAPROXY_CONFIG_CHECK_COMMAND, stdin=subprocess.PIPE, stdout=subprocess.PIPE, stderr=subprocess.PIPE)
+        output, err = p.communicate()
+        return_code = p.returncode
+        if (return_code != 0):
+          logger.error("Config check failed. NOT reloading haproxy")
+          logger.error(output)
+          logger.error(err)
+          return
+        else:
+          logger.info("Config check passed")
         # Reload haproxy
         logger.info("Reloading HAProxy")
         if timeout == -1:

tests/unit/helper/test_update_helper.py

@@ -24,11 +24,19 @@ def poll(self):
 
         def terminate(self):
             self.terminated = True
+            
+        def communicate(self):
+            return ("", "")
 
         pass
 
     class Object(object):
-        pass
+      returncode = 0
+      
+      def communicate(self):
+        return ("", "")
+      
+      pass
 
     @mock.patch("haproxy.helper.update_helper.subprocess.Popen")
     def test_run_graceful_reload_within_timeout(self, mock_popen):