Added has_image method to client-side Docker manager (fixes #316) (#317)

* added head method to API

* added has_image to client-side Docker manager

* added HEAD /docker/images/:name

* bug fix: bad var name

* updated changelog

* bug fix: use .get and catch error

CHANGELOG.md

@@ -4,6 +4,8 @@
 
 * Added `__contains__` to client- and server-side `BugManager`.
 * Added `__delitem__` to client- and server-side `BugManager`.
+* Added `head` method to client API interface.
+* Added `has_image` method to client-side Docker manager.
 
 
 ## 2.1.23 (2019-02-28)

bugzoo/client/api.py

@@ -14,6 +14,7 @@
 from ..exceptions import ConnectionFailure, UnexpectedResponse, BugZooException
 
 logger = logging.getLogger(__name__)  # type: logging.Logger
+logger.setLevel(logging.DEBUG)
 
 __all__ = ['APIClient']
 
@@ -109,6 +110,11 @@ def put(self, path: str, **kwargs) -> requests.Response:
         logger.debug('PUT: %s', url)
         return requests.put(url, **kwargs)
 
+    def head(self, path: str, **kwargs) -> requests.Response:
+        url = self._url(path)
+        logger.debug('HEAD: %s', url)
+        return requests.head(url, **kwargs)
+
     def patch(self, path: str, data, **kwargs ) -> requests.Response:
         url = self._url(path)
         logger.debug('PATCH: %s', url)

bugzoo/client/dockerm.py

@@ -5,6 +5,7 @@
 from .api import APIClient
 
 logger = logging.getLogger(__name__)  # type: logging.Logger
+logger.setLevel(logging.DEBUG)
 
 
 class DockerManager(object):
@@ -14,14 +15,26 @@ class DockerManager(object):
     def __init__(self, api: APIClient) -> None:
         self.__api = api
 
+    def has_image(self, name: str) -> bool:
+        """
+        Determines whether the server has a Docker image with a given name.
+        """
+        path = "docker/images/{}".format(name)
+        r = self.__api.head(path)
+        if r.status_code == 204:
+            return True
+        elif r.status_code == 404:
+            return False
+        self.__api.handle_erroneous_response(r)
+
     def delete_image(self, name: str) -> None:
         """
         Deletes a Docker image with a given name.
 
         Parameters:
             name: the name of the Docker image.
         """
-        logger.info("deleting Docker image: %s", name)
+        logger.debug("deleting Docker image: %s", name)
         path = "docker/images/{}".format(name)
         response = self.__api.delete(path)
         if response.status_code != 204:

bugzoo/server/__init__.py

@@ -580,6 +580,18 @@ def docker_images(name: str):
         return UnexpectedServerError.from_exception(ex), 500
 
 
+@app.route('/docker/images/<path:name>', methods=['GET', 'HEAD'])
+@throws_errors
+def has_docker_image(name: str):
+    try:
+        daemon.docker.images.get(name)
+        return '', 204
+    except docker.errors.ImageNotFound:
+        return '', 404
+    except Exception as ex:
+        return UnexpectedServerError.from_exception(ex), 500
+
+
 @app.route('/bugs/<uid>', methods=['DELETE'])
 @throws_errors
 def deregister_bug(uid: str):