Merge pull request #3340 from johnharris85/2922-config-does-not-catch-missing-links

Fix #2922: Config does not catch missing links

compose/config/config.py

@@ -37,6 +37,7 @@ from .validation import validate_against_config_schema
 from .validation import validate_config_section
 from .validation import validate_depends_on
 from .validation import validate_extends_file_path
+from .validation import validate_links
 from .validation import validate_network_mode
 from .validation import validate_service_constraints
 from .validation import validate_top_level_object
@@ -580,6 +581,7 @@ def validate_service(service_config, service_names, version):
     validate_ulimits(service_config)
     validate_network_mode(service_config, service_names)
     validate_depends_on(service_config, service_names)
+    validate_links(service_config, service_names)
 
     if not service_dict.get('image') and has_uppercase(service_name):
         raise ConfigurationError(

compose/config/validation.py

@@ -171,6 +171,14 @@ def validate_network_mode(service_config, service_names):
             "is undefined.".format(s=service_config, dep=dependency))
 
 
+def validate_links(service_config, service_names):
+    for link in service_config.config.get('links', []):
+        if link.split(':')[0] not in service_names:
+            raise ConfigurationError(
+                "Service '{s.name}' has a link to service '{link}' which is "
+                "undefined.".format(s=service_config, link=link))
+
+
 def validate_depends_on(service_config, service_names):
     for dependency in service_config.config.get('depends_on', []):
         if dependency not in service_names:

tests/fixtures/extends/invalid-links.yml

@@ -1,3 +1,5 @@
+mydb:
+  build: '.'
 myweb:
   build: '.'
   extends:

tests/unit/config/config_test.py

@@ -1360,6 +1360,17 @@ class ConfigTest(unittest.TestCase):
             config.load(config_details)
         assert "Service 'one' depends on service 'three'" in exc.exconly()
 
+    def test_linked_service_is_undefined(self):
+        with self.assertRaises(ConfigurationError):
+            config.load(
+                build_config_details({
+                    'version': '2',
+                    'services': {
+                        'web': {'image': 'busybox', 'links': ['db:db']},
+                    },
+                })
+            )
+
     def test_load_dockerfile_without_context(self):
         config_details = build_config_details({
             'version': '2',