Minor touchups for code clarity

Author: sodabrew

utils/service_discovery/config.py

@@ -16,17 +16,17 @@ def extract_agent_config(config):
     agentConfig = {}
 
     backend = config.get('Main', 'service_discovery_backend')
-    agentConfig['service_discovery'] = True
+    if backend in SD_BACKENDS:
+        agentConfig['service_discovery'] = True
+    else:
+        log.error("The backend {0} is not supported. "
+                  "Service discovery won't be enabled.".format(backend))
+        agentConfig['service_discovery'] = False
 
     conf_backend = None
     if config.has_option('Main', 'sd_config_backend'):
         conf_backend = config.get('Main', 'sd_config_backend')
 
-    if backend not in SD_BACKENDS:
-        log.error("The backend {0} is not supported. "
-                  "Service discovery won't be enabled.".format(backend))
-        agentConfig['service_discovery'] = False
-
     if conf_backend is None:
         log.debug('No configuration backend provided for service discovery. '
                   'Only auto config templates will be used.')

utils/service_discovery/sd_docker_backend.py

@@ -408,10 +408,9 @@ def get_configs(self):
                         else:
                             configs[check_name] = (source, (init_config, [instance]))
                     else:
-                        conflict_init_msg = 'Different versions of `init_config` found for check {}. ' \
-                            'Keeping the first one found.'
                         if configs[check_name][1][0] != init_config:
-                            log.warning(conflict_init_msg.format(check_name))
+                            log.warning('Different versions of `init_config` found for check %s. '
+                                'Keeping the first one found.' % check_name)
                         if isinstance(instance, list):
                             for inst in instance:
                                 configs[check_name][1][1].append(inst)