openpgp: Obtain debug logs from GnuPG

Signed-off-by: Michał Górny <mgorny@gentoo.org>

gemato/cli.py

@@ -99,7 +99,7 @@ def parse_args(self, args, argp):
             env_class = gemato.openpgp.OpenPGPEnvironment
         else:
             env_class = gemato.openpgp.OpenPGPSystemEnvironment
-        self.openpgp_env = env_class()
+        self.openpgp_env = env_class(debug=args.debug)
 
         if args.openpgp_key is not None:
             with io.open(args.openpgp_key, 'rb') as f:

gemato/openpgp.py

@@ -34,9 +34,10 @@ class OpenPGPSystemEnvironment(object):
     (user's home directory or GNUPGHOME).
     """
 
-    __slots__ = ['_impl']
+    __slots__ = ['debug', '_impl']
 
-    def __init__(self):
+    def __init__(self, debug=False):
+        self.debug = debug
         self._impl = None
 
     def __enter__(self):
@@ -189,28 +190,43 @@ class OpenPGPEnvironment(OpenPGPSystemEnvironment):
 
     __slots__ = ['_home']
 
-    def __init__(self):
-        super(OpenPGPEnvironment, self).__init__()
+    def __init__(self, debug=False):
+        super(OpenPGPEnvironment, self).__init__(debug=debug)
         self._home = tempfile.mkdtemp()
 
         with open(os.path.join(self._home, 'dirmngr.conf'), 'w') as f:
             f.write('''# autogenerated by gemato
 
 # honor user's http_proxy setting
 honor-http-proxy
-''')
+
+# enable debugging, in case we needed it
+log-file {debug_file}
+debug-level guru
+debug-all
+'''.format(debug_file=os.path.join(self._home, 'dirmngr.log')))
         with open(os.path.join(self._home, 'gpg.conf'), 'w') as f:
             f.write('''# autogenerated by gemato
 
 # we are using an isolated keyring, so always trust our keys
 trust-model always
-''')
+
+# enable debugging, in case we needed it
+log-file {debug_file}
+debug-level guru
+debug-all
+'''.format(debug_file=os.path.join(self._home, 'gpg.log')))
         with open(os.path.join(self._home, 'gpg-agent.conf'), 'w') as f:
             f.write('''# autogenerated by gemato
 
 # avoid any smartcard operations, we are running in isolation
 disable-scdaemon
-''')
+
+# enable debugging, in case we needed it
+log-file {debug_file}
+debug-level guru
+debug-all
+'''.format(debug_file=os.path.join(self._home, 'gpg-agent.log')))
 
     def __exit__(self, exc_type, exc_value, exc_cb):
         if self._home is not None:
@@ -234,9 +250,14 @@ def _rmtree_error_handler(func, path, exc_info):
 
     def close(self):
         if self._home is not None:
-            # we need to loop due to ENOTEMPTY potential
-            while os.path.isdir(self._home):
-                shutil.rmtree(self._home, onerror=self._rmtree_error_handler)
+            if not self.debug:
+                # we need to loop due to ENOTEMPTY potential
+                while os.path.isdir(self._home):
+                    shutil.rmtree(self._home,
+                                  onerror=self._rmtree_error_handler)
+            else:
+                logging.debug('GNUPGHOME left for debug purposes: {}'
+                              .format(self._home))
             self._home = None
 
     def import_key(self, keyfile):