python: Fix teardown of ephemeral contexts.

* lang/python/tests/support.py (EphemeralContext): New function.
* lang/python/tests/t-quick-key-creation.py: Use the new function to
manage ephemeral contexts.
* lang/python/tests/t-quick-key-manipulation.py: Likewise.
* lang/python/tests/t-quick-subkey-creation.py: Likewise.
--

Previously, there was a problem with cleaning up ephemeral home
directories.  shutil.rmtree deleted the agents main socket, gpg-agent
detected that, and deleted the other sockets as well, racing
shutil.rmtree which did not cope will with that.

Fix this by asking the agent nicely to shut down.

Signed-off-by: Justus Winter <justus@g10code.com>

lang/python/tests/support.py

@@ -18,9 +18,12 @@
 from __future__ import absolute_import, print_function, unicode_literals
 del absolute_import, print_function, unicode_literals
 
+import contextlib
+import shutil
 import sys
 import os
 import tempfile
+import time
 import gpg
 
 # known keys
@@ -85,5 +88,24 @@ else:
             self.path = tempfile.mkdtemp()
             return self.path
         def __exit__(self, *args):
-            import shutil
             shutil.rmtree(self.path)
+
+@contextlib.contextmanager
+def EphemeralContext():
+    with TemporaryDirectory() as tmp:
+        home = os.environ['GNUPGHOME']
+        shutil.copy(os.path.join(home, "gpg.conf"), tmp)
+        shutil.copy(os.path.join(home, "gpg-agent.conf"), tmp)
+
+        with gpg.Context(home_dir=tmp) as ctx:
+            yield ctx
+
+            # Ask the agent to quit.
+            agent_socket = os.path.join(tmp, "S.gpg-agent")
+            ctx.protocol = gpg.constants.protocol.ASSUAN
+            ctx.set_engine_info(ctx.protocol, file_name=agent_socket)
+            ctx.assuan_transact(["KILLAGENT"])
+
+            # Block until it is really gone.
+            while os.path.exists(agent_socket):
+                time.sleep(.01)

lang/python/tests/t-quick-key-creation.py

@@ -22,22 +22,13 @@ del absolute_import, print_function, unicode_literals
 
 import gpg
 import itertools
-import os
-import shutil
 import time
 
 import support
 
 alpha = "Alpha <alpha@invalid.example.net>"
 
-def copy_configuration(destination):
+with support.EphemeralContext() as ctx:
-    home = os.environ['GNUPGHOME']
-    shutil.copy(os.path.join(home, "gpg.conf"), destination)
-    shutil.copy(os.path.join(home, "gpg-agent.conf"), destination)
-
-with support.TemporaryDirectory() as tmp:
-    copy_configuration(tmp)
-    with gpg.Context(home_dir=tmp) as ctx:
     res = ctx.create_key(alpha)
 
     keys = list(ctx.keylist())
@@ -67,10 +58,7 @@ def make_uid():
     uid_counter += 1
     return "user{0}@invalid.example.org".format(uid_counter)
 
-with support.TemporaryDirectory() as tmp:
+with support.EphemeralContext() as ctx:
-    copy_configuration(tmp)
-    with gpg.Context(home_dir=tmp) as ctx:
-
     # Check gpg.constants.create.NOEXPIRE...
     res = ctx.create_key(make_uid(), expires=False)
     key = ctx.get_key(res.fpr, secret=True)

lang/python/tests/t-quick-key-manipulation.py

@@ -21,24 +21,13 @@ from __future__ import absolute_import, print_function, unicode_literals
 del absolute_import, print_function, unicode_literals
 
 import gpg
-import itertools
-import os
-import shutil
-import time
 
 import support
 
 alpha = "Alpha <alpha@invalid.example.net>"
 bravo = "Bravo <bravo@invalid.example.net>"
 
-def copy_configuration(destination):
+with support.EphemeralContext() as ctx:
-    home = os.environ['GNUPGHOME']
-    shutil.copy(os.path.join(home, "gpg.conf"), destination)
-    shutil.copy(os.path.join(home, "gpg-agent.conf"), destination)
-
-with support.TemporaryDirectory() as tmp:
-    copy_configuration(tmp)
-    with gpg.Context(home_dir=tmp) as ctx:
     res = ctx.create_key(alpha, certify=True)
     key = ctx.get_key(res.fpr)
     assert len(key.subkeys) == 1, "Expected one primary key and no subkeys"

lang/python/tests/t-quick-subkey-creation.py

@@ -22,8 +22,6 @@ del absolute_import, print_function, unicode_literals
 
 import gpg
 import itertools
-import os
-import shutil
 import time
 
 import support
@@ -31,14 +29,7 @@ import support
 alpha = "Alpha <alpha@invalid.example.net>"
 bravo = "Bravo <bravo@invalid.example.net>"
 
-def copy_configuration(destination):
+with support.EphemeralContext() as ctx:
-    home = os.environ['GNUPGHOME']
-    shutil.copy(os.path.join(home, "gpg.conf"), destination)
-    shutil.copy(os.path.join(home, "gpg-agent.conf"), destination)
-
-with support.TemporaryDirectory() as tmp:
-    copy_configuration(tmp)
-    with gpg.Context(home_dir=tmp) as ctx:
     res = ctx.create_key(alpha, certify=True)
     keys = list(ctx.keylist())
     assert len(keys) == 1, "Weird number of keys created"