Support links when creating containers or connecting to networks

Signed-off-by: Aanand Prasad <aanand.prasad@gmail.com>

docker/api/network.py

 import json
 
-from ..utils import check_resource, minimum_version
+from ..utils import check_resource, minimum_version, normalize_links
 
 
 class NetworkApiMixin(object):
@@ -47,11 +47,13 @@ class NetworkApiMixin(object):
 
     @check_resource
     @minimum_version('1.21')
-    def connect_container_to_network(self, container, net_id, aliases=None):
+    def connect_container_to_network(self, container, net_id,
+                                     aliases=None, links=None):
         data = {
             "Container": container,
             "EndpointConfig": {
                 "Aliases": aliases,
+                "Links": normalize_links(links) if links else None,
             },
         }
         url = self._url("/networks/{0}/connect", net_id)

docker/utils/__init__.py

@@ -4,7 +4,7 @@ from .utils import (
     kwargs_from_env, convert_filters, datetime_to_timestamp, create_host_config,
     create_container_config, parse_bytes, ping_registry, parse_env_file,
     version_lt, version_gte, decode_json_header, split_command,
-    create_ipam_config, create_ipam_pool, parse_devices
+    create_ipam_config, create_ipam_pool, parse_devices, normalize_links,
 ) # flake8: noqa
 
 from .types import Ulimit, LogConfig # flake8: noqa

docker/utils/utils.py

@@ -674,12 +674,7 @@ def create_host_config(binds=None, port_bindings=None, lxc_conf=None,
         host_config['ExtraHosts'] = extra_hosts
 
     if links is not None:
-        if isinstance(links, dict):
-            links = six.iteritems(links)
-
-        formatted_links = ['{0}:{1}'.format(k, v) for k, v in sorted(links)]
-
-        host_config['Links'] = formatted_links
+        host_config['Links'] = normalize_links(links)
 
     if isinstance(lxc_conf, dict):
         formatted = []
@@ -731,6 +726,13 @@ def create_host_config(binds=None, port_bindings=None, lxc_conf=None,
     return host_config
 
 
+def normalize_links(links):
+    if isinstance(links, dict):
+        links = six.iteritems(links)
+
+    return ['{0}:{1}'.format(k, v) for k, v in sorted(links)]
+
+
 def create_networking_config(endpoints_config=None):
     networking_config = {}
 
@@ -740,7 +742,7 @@ def create_networking_config(endpoints_config=None):
     return networking_config
 
 
-def create_endpoint_config(version, aliases=None):
+def create_endpoint_config(version, aliases=None, links=None):
     endpoint_config = {}
 
     if aliases:
@@ -748,6 +750,11 @@ def create_endpoint_config(version, aliases=None):
             raise host_config_version_error('endpoint_config.aliases', '1.22')
         endpoint_config["Aliases"] = aliases
 
+    if links:
+        if version_lt(version, '1.22'):
+            raise host_config_version_error('endpoint_config.links', '1.22')
+        endpoint_config["Links"] = normalize_links(links)
+
     return endpoint_config
 
 

tests/helpers.py

@@ -168,3 +168,18 @@ class BaseTestCase(unittest.TestCase):
                 .format(exitcode, output))
 
         return container
+
+    def create_and_start(self, image='busybox', command='top', **kwargs):
+        container = self.client.create_container(
+            image=image, command=command, **kwargs)
+        self.tmp_containers.append(container)
+        self.client.start(container)
+        return container
+
+    def execute(self, container, cmd, exit_code=0, **kwargs):
+        exc = self.client.exec_create(container, cmd, **kwargs)
+        output = self.client.exec_start(exc)
+        actual_exit_code = self.client.exec_inspect(exc)['ExitCode']
+        msg = "Expected `{}` to exit with code {} but returned {}:\n{}".format(
+            " ".join(cmd), exit_code, actual_exit_code, output)
+        assert actual_exit_code == exit_code, msg

tests/integration/network_test.py

@@ -180,3 +180,52 @@ class TestNetworks(helpers.BaseTestCase):
         self.assertEqual(
             container_data['NetworkSettings']['Networks'][net_name]['Aliases'],
             ['foo', 'bar'])
+
+    @requires_api_version('1.22')
+    def test_create_with_links(self):
+        net_name, net_id = self.create_network()
+
+        container = self.create_and_start(
+            host_config=self.client.create_host_config(network_mode=net_name),
+            networking_config=self.client.create_networking_config({
+                net_name: self.client.create_endpoint_config(
+                    links=[('docker-py-test-upstream', 'bar')],
+                ),
+            }),
+        )
+
+        container_data = self.client.inspect_container(container)
+        self.assertEqual(
+            container_data['NetworkSettings']['Networks'][net_name]['Links'],
+            ['docker-py-test-upstream:bar'])
+
+        self.create_and_start(
+            name='docker-py-test-upstream',
+            host_config=self.client.create_host_config(network_mode=net_name),
+        )
+
+        self.execute(container, ['nslookup', 'bar'])
+
+    @requires_api_version('1.22')
+    def test_connect_with_links(self):
+        net_name, net_id = self.create_network()
+
+        container = self.create_and_start(
+            host_config=self.client.create_host_config(network_mode=net_name))
+
+        self.client.disconnect_container_from_network(container, net_name)
+        self.client.connect_container_to_network(
+            container, net_name,
+            links=[('docker-py-test-upstream', 'bar')])
+
+        container_data = self.client.inspect_container(container)
+        self.assertEqual(
+            container_data['NetworkSettings']['Networks'][net_name]['Links'],
+            ['docker-py-test-upstream:bar'])
+
+        self.create_and_start(
+            name='docker-py-test-upstream',
+            host_config=self.client.create_host_config(network_mode=net_name),
+        )
+
+        self.execute(container, ['nslookup', 'bar'])

tests/unit/network_test.py

@@ -150,6 +150,7 @@ class NetworkTest(DockerClientTest):
                 {'Id': container_id},
                 network_id,
                 aliases=['foo', 'bar'],
+                links=[('baz', 'quux')]
             )
 
         self.assertEqual(
@@ -162,6 +163,7 @@ class NetworkTest(DockerClientTest):
                 'Container': container_id,
                 'EndpointConfig': {
                     'Aliases': ['foo', 'bar'],
+                    'Links': ['baz:quux'],
                 },
             })