Merge pull request #747 from tseaver/741-hoist_gae_gcd_detection

#741: hoist GAE/GCD detection into `gcloud._helpers`

Author: tseaver

gcloud/_helpers.py

@@ -15,13 +15,21 @@
 
 This module is not part of the public API surface of `gcloud`.
 """
+import socket
 
 try:
     from threading import local as Local
 except ImportError:     # pragma: NO COVER (who doesn't have it?)
     class Local(object):
         """Placeholder for non-threaded applications."""
 
+from six.moves.http_client import HTTPConnection  # pylint: disable=F0401
+
+try:
+    from google.appengine.api import app_identity
+except ImportError:
+    app_identity = None
+
 
 class _LocalStack(Local):
     """Manage a thread-local LIFO stack of resources.
@@ -102,3 +110,49 @@ def _lazy_property_deco(deferred_callable):
         #      For Python2.7+ deferred_callable.__func__ would suffice.
         deferred_callable = deferred_callable.__get__(True)
     return _LazyProperty(deferred_callable.__name__, deferred_callable)
+
+
+def _app_engine_id():
+    """Gets the App Engine application ID if it can be inferred.
+
+    :rtype: string or ``NoneType``
+    :returns: App Engine application ID if running in App Engine,
+              else ``None``.
+    """
+    if app_identity is None:
+        return None
+
+    return app_identity.get_application_id()
+
+
+def _compute_engine_id():
+    """Gets the Compute Engine project ID if it can be inferred.
+
+    Uses 169.254.169.254 for the metadata server to avoid request
+    latency from DNS lookup.
+
+    See https://cloud.google.com/compute/docs/metadata#metadataserver
+    for information about this IP address. (This IP is also used for
+    Amazon EC2 instances, so the metadata flavor is crucial.)
+
+    See https://github.com/google/oauth2client/issues/93 for context about
+    DNS latency.
+
+    :rtype: string or ``NoneType``
+    :returns: Compute Engine project ID if the metadata service is available,
+              else ``None``.
+    """
+    host = '169.254.169.254'
+    uri_path = '/computeMetadata/v1/project/project-id'
+    headers = {'Metadata-Flavor': 'Google'}
+    connection = HTTPConnection(host, timeout=0.1)
+
+    try:
+        connection.request('GET', uri_path, headers=headers)
+        response = connection.getresponse()
+        if response.status == 200:
+            return response.read()
+    except socket.error:  # socket.timeout or socket.error(64, 'Host is down')
+        pass
+    finally:
+        connection.close()

gcloud/datastore/_implicit_environ.py

@@ -19,15 +19,9 @@
 """
 
 import os
-import socket
-
-from six.moves.http_client import HTTPConnection  # pylint: disable=F0401
-
-try:
-    from google.appengine.api import app_identity
-except ImportError:
-    app_identity = None
 
+from gcloud._helpers import _app_engine_id
+from gcloud._helpers import _compute_engine_id
 from gcloud._helpers import _lazy_property_deco
 from gcloud import credentials
 from gcloud.datastore.connection import Connection
@@ -41,52 +35,6 @@
 _GCD_DATASET_ENV_VAR_NAME = 'DATASTORE_DATASET'
 
 
-def app_engine_id():
-    """Gets the App Engine application ID if it can be inferred.
-
-    :rtype: string or ``NoneType``
-    :returns: App Engine application ID if running in App Engine,
-              else ``None``.
-    """
-    if app_identity is None:
-        return None
-
-    return app_identity.get_application_id()
-
-
-def compute_engine_id():
-    """Gets the Compute Engine project ID if it can be inferred.
-
-    Uses 169.254.169.254 for the metadata server to avoid request
-    latency from DNS lookup.
-
-    See https://cloud.google.com/compute/docs/metadata#metadataserver
-    for information about this IP address. (This IP is also used for
-    Amazon EC2 instances, so the metadata flavor is crucial.)
-
-    See https://github.com/google/oauth2client/issues/93 for context about
-    DNS latency.
-
-    :rtype: string or ``NoneType``
-    :returns: Compute Engine project ID if the metadata service is available,
-              else ``None``.
-    """
-    host = '169.254.169.254'
-    uri_path = '/computeMetadata/v1/project/project-id'
-    headers = {'Metadata-Flavor': 'Google'}
-    connection = HTTPConnection(host, timeout=0.1)
-
-    try:
-        connection.request('GET', uri_path, headers=headers)
-        response = connection.getresponse()
-        if response.status == 200:
-            return response.read()
-    except socket.error:  # socket.timeout or socket.error(64, 'Host is down')
-        pass
-    finally:
-        connection.close()
-
-
 def _get_production_dataset_id():
     """Gets the production application ID if it can be inferred."""
     return os.getenv(_DATASET_ENV_VAR_NAME)
@@ -121,10 +69,10 @@ def _determine_default_dataset_id(dataset_id=None):
         dataset_id = _get_gcd_dataset_id()
 
     if dataset_id is None:
-        dataset_id = app_engine_id()
+        dataset_id = _app_engine_id()
 
     if dataset_id is None:
-        dataset_id = compute_engine_id()
+        dataset_id = _compute_engine_id()
 
     return dataset_id
 

gcloud/datastore/test__implicit_environ.py

@@ -121,68 +121,6 @@ def test_value_set(self):
             self.assertEqual(dataset_id, MOCK_DATASET_ID)
 
 
-class Test_app_engine_id(unittest2.TestCase):
-
-    def _callFUT(self):
-        from gcloud.datastore import _implicit_environ
-        return _implicit_environ.app_engine_id()
-
-    def test_no_value(self):
-        from gcloud._testing import _Monkey
-        from gcloud.datastore import _implicit_environ
-
-        with _Monkey(_implicit_environ, app_identity=None):
-            dataset_id = self._callFUT()
-            self.assertEqual(dataset_id, None)
-
-    def test_value_set(self):
-        from gcloud._testing import _Monkey
-        from gcloud.datastore import _implicit_environ
-
-        APP_ENGINE_ID = object()
-        APP_IDENTITY = _AppIdentity(APP_ENGINE_ID)
-        with _Monkey(_implicit_environ, app_identity=APP_IDENTITY):
-            dataset_id = self._callFUT()
-            self.assertEqual(dataset_id, APP_ENGINE_ID)
-
-
-class Test_compute_engine_id(unittest2.TestCase):
-
-    def _callFUT(self):
-        from gcloud.datastore import _implicit_environ
-        return _implicit_environ.compute_engine_id()
-
-    def _monkeyConnection(self, connection):
-        from gcloud._testing import _Monkey
-        from gcloud.datastore import _implicit_environ
-
-        def _factory(host, timeout):
-            connection.host = host
-            connection.timeout = timeout
-            return connection
-
-        return _Monkey(_implicit_environ, HTTPConnection=_factory)
-
-    def test_bad_status(self):
-        connection = _HTTPConnection(404, None)
-        with self._monkeyConnection(connection):
-            dataset_id = self._callFUT()
-            self.assertEqual(dataset_id, None)
-
-    def test_success(self):
-        COMPUTE_ENGINE_ID = object()
-        connection = _HTTPConnection(200, COMPUTE_ENGINE_ID)
-        with self._monkeyConnection(connection):
-            dataset_id = self._callFUT()
-            self.assertEqual(dataset_id, COMPUTE_ENGINE_ID)
-
-    def test_socket_raises(self):
-        connection = _TimeoutHTTPConnection()
-        with self._monkeyConnection(connection):
-            dataset_id = self._callFUT()
-            self.assertEqual(dataset_id, None)
-
-
 class Test__determine_default_dataset_id(unittest2.TestCase):
 
     def _callFUT(self, dataset_id=None):
@@ -216,8 +154,8 @@ def gce_mock():
         patched_methods = {
             '_get_production_dataset_id': prod_mock,
             '_get_gcd_dataset_id': gcd_mock,
-            'app_engine_id': gae_mock,
-            'compute_engine_id': gce_mock,
+            '_app_engine_id': gae_mock,
+            '_compute_engine_id': gce_mock,
         }
 
         with _Monkey(_implicit_environ, **patched_methods):
@@ -412,57 +350,3 @@ def test_set_implicit(self):
             self._callFUT()
 
         self.assertEqual(_implicit_environ.get_default_connection(), fake_cnxn)
-
-
-class _AppIdentity(object):
-
-    def __init__(self, app_id):
-        self.app_id = app_id
-
-    def get_application_id(self):
-        return self.app_id
-
-
-class _HTTPResponse(object):
-
-    def __init__(self, status, data):
-        self.status = status
-        self.data = data
-
-    def read(self):
-        return self.data
-
-
-class _BaseHTTPConnection(object):
-
-    host = timeout = None
-
-    def __init__(self):
-        self._close_count = 0
-        self._called_args = []
-        self._called_kwargs = []
-
-    def request(self, method, uri, **kwargs):
-        self._called_args.append((method, uri))
-        self._called_kwargs.append(kwargs)
-
-    def close(self):
-        self._close_count += 1
-
-
-class _HTTPConnection(_BaseHTTPConnection):
-
-    def __init__(self, status, project_id):
-        super(_HTTPConnection, self).__init__()
-        self.status = status
-        self.project_id = project_id
-
-    def getresponse(self):
-        return _HTTPResponse(self.status, self.project_id)
-
-
-class _TimeoutHTTPConnection(_BaseHTTPConnection):
-
-    def getresponse(self):
-        import socket
-        raise socket.timeout('timed out')