Don't use dot as a path separator as it is a valid character in resource identifiers

Signed-off-by: Joffrey F <joffrey@docker.com>

compose/config/interpolation.py

@@ -48,7 +48,7 @@ def interpolate_environment_variables(version, config, section, environment):
 
 
 def get_config_path(config_key, section, name):
-    return '{}.{}.{}'.format(section, name, config_key)
+    return '{}/{}/{}'.format(section, name, config_key)
 
 
 def interpolate_value(name, config_key, value, section, interpolator):
@@ -75,7 +75,7 @@ def interpolate_value(name, config_key, value, section, interpolator):
 
 def recursive_interpolate(obj, interpolator, config_path):
     def append(config_path, key):
-        return '{}.{}'.format(config_path, key)
+        return '{}/{}'.format(config_path, key)
 
     if isinstance(obj, six.string_types):
         return converter.convert(config_path, interpolator.interpolate(obj))
@@ -160,12 +160,12 @@ class UnsetRequiredSubstitution(Exception):
         self.err = custom_err_msg
 
 
-PATH_JOKER = '[^.]+'
+PATH_JOKER = '[^/]+'
 FULL_JOKER = '.+'
 
 
 def re_path(*args):
-    return re.compile('^{}$'.format('\.'.join(args)))
+    return re.compile('^{}$'.format('/'.join(args)))
 
 
 def re_path_basic(section, name):
@@ -288,7 +288,7 @@ class ConversionMap(object):
                 except ValueError as e:
                     raise ConfigurationError(
                         'Error while attempting to convert {} to appropriate type: {}'.format(
-                            path, e
+                            path.replace('/', '.'), e
                         )
                     )
         return value

tests/unit/config/interpolation_test.py

@@ -332,6 +332,37 @@ def test_interpolate_environment_external_resource_convert_types(mock_env):
     assert value == expected
 
 
+def test_interpolate_service_name_uses_dot(mock_env):
+    entry = {
+        'service.1': {
+            'image': 'busybox',
+            'ulimits': {
+                'nproc': '${POSINT}',
+                'nofile': {
+                    'soft': '${POSINT}',
+                    'hard': '${DEFAULT:-40000}'
+                },
+            },
+        }
+    }
+
+    expected = {
+        'service.1': {
+            'image': 'busybox',
+            'ulimits': {
+                'nproc': 50,
+                'nofile': {
+                    'soft': 50,
+                    'hard': 40000
+                },
+            },
+        }
+    }
+
+    value = interpolate_environment_variables(V3_4, entry, 'service', mock_env)
+    assert value == expected
+
+
 def test_escaped_interpolation(defaults_interpolator):
     assert defaults_interpolator('$${foo}') == '${foo}'