Add integration test and docs for build with a git url.

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

compose/config/config.py

@@ -564,7 +564,8 @@ def validate_paths(service_dict):
             (not os.path.exists(build_path) or not os.access(build_path, os.R_OK))
         ):
             raise ConfigurationError(
-                "build path %s either does not exist or is not accessible." % build_path)
+                "build path %s either does not exist, is not accessible, "
+                "or is not a valid URL." % build_path)
 
 
 def merge_path_mappings(base, override):

docs/compose-file.md

@@ -31,15 +31,18 @@ definition.
 
 ### build
 
-Path to a directory containing a Dockerfile. When the value supplied is a
+Either a path to a directory containing a Dockerfile, or a url to a git repository.
-relative path, it is interpreted as relative to the location of the yml file
+
-itself. This directory is also the build context that is sent to the Docker daemon.
+When the value supplied is a relative path, it is interpreted as relative to the
+location of the Compose file. This directory is also the build context that is
+sent to the Docker daemon.
 
 Compose will build and tag it with a generated name, and use that image thereafter.
 
     build: /path/to/build/dir
 
-Using `build` together with `image` is not allowed. Attempting to do so results in an error.
+Using `build` together with `image` is not allowed. Attempting to do so results in
+an error.
 
 ### cap_add, cap_drop
 

tests/integration/service_test.py

@@ -507,6 +507,13 @@ class ServiceTest(DockerClientTestCase):
         self.create_service('web', build=text_type(base_dir)).build()
         self.assertEqual(len(self.client.images(name='composetest_web')), 1)
 
+    def test_build_with_git_url(self):
+        build_url = "https://github.com/dnephin/docker-build-from-url.git"
+        service = self.create_service('buildwithurl', build=build_url)
+        self.addCleanup(self.client.remove_image, service.image_name)
+        service.build()
+        assert service.image()
+
     def test_start_container_stays_unpriviliged(self):
         service = self.create_service('web')
         container = create_and_start_container(service).inspect()

tests/unit/config/config_test.py

@@ -1497,13 +1497,14 @@ class BuildPathTest(unittest.TestCase):
         service_dict = load_from_filename('tests/fixtures/build-path/docker-compose.yml')
         self.assertEquals(service_dict, [{'name': 'foo', 'build': self.abs_context_path}])
 
-    def test_valid_url_path(self):
+    def test_valid_url_in_build_path(self):
         valid_urls = [
             'git://github.com/docker/docker',
             'git@github.com:docker/docker.git',
             'git@bitbucket.org:atlassianlabs/atlassian-docker.git',
             'https://github.com/docker/docker.git',
             'http://github.com/docker/docker.git',
+            'github.com/docker/docker.git',
         ]
         for valid_url in valid_urls:
             service_dict = config.load(build_config_details({
@@ -1511,6 +1512,19 @@ class BuildPathTest(unittest.TestCase):
             }, '.', None))
             assert service_dict[0]['build'] == valid_url
 
+    def test_invalid_url_in_build_path(self):
+        invalid_urls = [
+            'example.com/bogus',
+            'ftp://example.com/',
+            '/path/does/not/exist',
+        ]
+        for invalid_url in invalid_urls:
+            with pytest.raises(ConfigurationError) as exc:
+                config.load(build_config_details({
+                    'invalidurl': {'build': invalid_url},
+                }, '.', None))
+            assert 'build path' in exc.exconly()
+
 
 class GetDefaultConfigFilesTestCase(unittest.TestCase):