close #170 .

add --check-config option to check the config and app loading.

gunicorn/app/base.py

@@ -102,6 +102,19 @@ class Application(object):
         return self.callable
 
     def run(self):
+        if self.cfg.check_config:
+            try:
+
+                self.load()
+            except:
+                sys.stderr.write("\nError while loading the application:\n\n")
+                traceback.print_exc()
+
+                sys.stderr.flush()
+                sys.exit(1)
+
+            sys.exit(0)
+
         if self.cfg.spew:
             debug.spew()
         if self.cfg.daemon:

gunicorn/config.py

@@ -507,6 +507,17 @@ class Spew(Setting):
         This is the nuclear option.
         """
 
+class ConfigCheck(Setting):
+    name = "check_config"
+    section = "Debugging"
+    cli = ["--check-config",]
+    validator = validate_bool
+    action = "store_true"
+    default = False
+    desc = """\
+        Check the configuration..
+        """
+
 class PreloadApp(Setting):
     name = "preload_app"
     section = "Server Mechanics"