Improve error when service is not a dict

Fixes #127

fig/cli/main.py

@@ -8,7 +8,7 @@ import signal
 from inspect import getdoc
 
 from .. import __version__
-from ..project import NoSuchService, DependencyError
+from ..project import NoSuchService, ConfigurationError
 from ..service import CannotBeScaledError
 from .command import Command
 from .formatter import Formatter
@@ -40,7 +40,7 @@ def main():
     except KeyboardInterrupt:
         log.error("\nAborting.")
         sys.exit(1)
-    except (UserError, NoSuchService, DependencyError) as e:
+    except (UserError, NoSuchService, ConfigurationError) as e:
         log.error(e.msg)
         sys.exit(1)
     except NoSuchCommand as e:

fig/project.py

@@ -67,6 +67,8 @@ class Project(object):
     def from_config(cls, name, config, client):
         dicts = []
         for service_name, service in list(config.items()):
+            if not isinstance(service, dict):
+                raise ConfigurationError('Service "%s" doesn\'t have any configuration options. All top level keys in your fig.yml must map to a dictionary of configuration options.')
             service['name'] = service_name
             dicts.append(service)
         return cls.from_dicts(name, dicts, client)
@@ -156,9 +158,13 @@ class NoSuchService(Exception):
         return self.msg
 
 
-class DependencyError(Exception):
+class ConfigurationError(Exception):
     def __init__(self, msg):
         self.msg = msg
 
     def __str__(self):
         return self.msg
+
+class DependencyError(ConfigurationError):
+    pass
+