Don't initialize networks that aren't used by any services.

Signed-off-by: Daniel Nephin <dnephin@docker.com>

compose/cli/main.py

@@ -693,7 +693,7 @@ def run_one_off_container(container_options, project, service, options):
                 start_deps=True,
                 strategy=ConvergenceStrategy.never)
 
-    project.initialize_networks()
+    project.initialize()
 
     container = service.create_container(
         quiet=True,

compose/network.py

@@ -133,12 +133,17 @@ class ProjectNetworks(object):
 
     @classmethod
     def from_services(cls, services, networks, use_networking):
-        networks = {
+        service_networks = {
-            network: networks[network]
+            network: networks.get(network)
             for service in services
             for network in service.get('networks', ['default'])
         }
-        return cls(networks, use_networking)
+        unused = set(networks) - set(service_networks) - {'default'}
+        if unused:
+            log.warn(
+                "Some networks were defined but are not used by any service: "
+                "{}".format(", ".join(unused)))
+        return cls(service_networks, use_networking)
 
     def remove(self):
         if not self.use_networking:

compose/project.py

@@ -351,13 +351,12 @@ class Project(object):
            timeout=DEFAULT_TIMEOUT,
            detached=False):
 
-        services = self.get_services_without_duplicate(service_names, include_deps=start_deps)
+        self.initialize()
+        services = self.get_services_without_duplicate(
+            service_names,
+            include_deps=start_deps)
 
         plans = self._get_convergence_plans(services, strategy)
-
-        self.networks.initialize()
-        self.initialize_volumes()
-
         return [
             container
             for service in services
@@ -369,6 +368,10 @@ class Project(object):
             )
         ]
 
+    def initialize(self):
+        self.networks.initialize()
+        self.initialize_volumes()
+
     def _get_convergence_plans(self, services, strategy):
         plans = {}
 

tests/acceptance/cli_test.py

@@ -406,7 +406,8 @@ class CLITestCase(DockerClientTestCase):
 
         services = self.project.get_services()
 
-        networks = self.client.networks(names=[self.project.default_network.full_name])
+        network_name = self.project.networks.networks['default']
+        networks = self.client.networks(names=[network_name])
         self.assertEqual(len(networks), 1)
         self.assertEqual(networks[0]['Driver'], 'bridge')
         assert 'com.docker.network.bridge.enable_icc' not in networks[0]['Options']
@@ -439,7 +440,9 @@ class CLITestCase(DockerClientTestCase):
 
         self.dispatch(['-f', filename, 'up', '-d'], None)
 
-        networks = self.client.networks(names=[self.project.default_network.full_name])
+        network_name = self.project.networks.networks['default']
+        networks = self.client.networks(names=[network_name])
+
         assert networks[0]['Options']['com.docker.network.bridge.enable_icc'] == 'false'
 
     @v2_only()
@@ -586,18 +589,15 @@ class CLITestCase(DockerClientTestCase):
             n['Name'] for n in self.client.networks()
             if n['Name'].startswith('{}_'.format(self.project.name))
         ]
-
+        assert network_names == []
-        assert sorted(network_names) == [
-            '{}_{}'.format(self.project.name, name)
-            for name in ['bar', 'foo']
-        ]
 
     def test_up_with_links_v1(self):
         self.base_dir = 'tests/fixtures/links-composefile'
         self.dispatch(['up', '-d', 'web'], None)
 
         # No network was created
-        networks = self.client.networks(names=[self.project.default_network.full_name])
+        network_name = self.project.networks.networks['default']
+        networks = self.client.networks(names=[network_name])
         assert networks == []
 
         web = self.project.get_service('web')

tests/integration/project_test.py

@@ -565,6 +565,7 @@ class ProjectTest(DockerClientTestCase):
                 'name': 'web',
                 'image': 'busybox:latest',
                 'command': 'top',
+                'networks': ['foo', 'bar', 'baz'],
             }],
             volumes={},
             networks={
@@ -594,7 +595,11 @@ class ProjectTest(DockerClientTestCase):
     def test_up_with_ipam_config(self):
         config_data = config.Config(
             version=V2_0,
-            services=[],
+            services=[{
+                'name': 'web',
+                'image': 'busybox:latest',
+                'networks': ['front'],
+            }],
             volumes={},
             networks={
                 'front': {