config: Add Config.rt_wrapper method.

This returns a cached version of the new rtutil.RT class,
so that a single process can easily grab references to one
instance with one cache of ticket/attachment data, etc.

conservancy_beancount/config.py

@@ -14,6 +14,7 @@
 # You should have received a copy of the GNU Affero General Public License
 # along with this program.  If not, see <https://www.gnu.org/licenses/>.
 
+import functools
 import os
 import urllib.parse as urlparse
 
@@ -27,6 +28,8 @@ from typing import (
     Type,
 )
 
+from . import rtutil
+
 class RTCredentials(NamedTuple):
     server: Optional[str] = None
     user: Optional[str] = None
@@ -99,3 +102,19 @@ class Config:
             return retval
         else:
             return None
+
+    @functools.lru_cache(4)
+    def _rt_wrapper(self, credentials: RTCredentials, client: Type[rt.Rt]) -> Optional[rtutil.RT]:
+        wrapper_client = self.rt_client(credentials, client)
+        if wrapper_client is None:
+            return None
+        else:
+            return rtutil.RT(wrapper_client)
+
+    def rt_wrapper(self,
+                  credentials: RTCredentials=None,
+                  client: Type[rt.Rt]=rt.Rt,
+    ) -> Optional[rtutil.RT]:
+        if credentials is None:
+            credentials = self.rt_credentials()
+        return self._rt_wrapper(credentials, client)

tests/test_config.py

@@ -158,3 +158,49 @@ def test_no_rt_client_without_server():
     rt_credentials = RT_GENERIC_CREDS._replace(server=None, auth='rt')
     config = config_mod.Config()
     assert config.rt_client(rt_credentials, testutil.RTClient) is None
+
+def test_rt_wrapper():
+    config = config_mod.Config()
+    rt = config.rt_wrapper(RT_GENERIC_CREDS._replace(auth='rt'), testutil.RTClient)
+    assert rt.exists(1)
+
+def test_rt_wrapper_default_creds():
+    config = config_mod.Config()
+    rt = config.rt_wrapper(None, testutil.RTClient)
+    assert rt.rt.url.startswith(RT_FILE_CREDS[0])
+
+def test_rt_wrapper_default_creds_from_environ(rt_environ):
+    with update_environ(**rt_environ):
+        config = config_mod.Config()
+        rt = config.rt_wrapper(None, testutil.RTClient)
+    assert rt.rt.url.startswith(RT_ENV_CREDS[0])
+
+def test_rt_wrapper_no_creds():
+    with update_environ(HOME=testutil.TESTS_DIR):
+        config = config_mod.Config()
+        assert config.rt_wrapper(None, testutil.RTClient) is None
+
+def test_rt_wrapper_bad_creds():
+    rt_credentials = RT_GENERIC_CREDS._replace(passwd='badpass', auth='rt')
+    config = config_mod.Config()
+    assert config.rt_wrapper(rt_credentials, testutil.RTClient) is None
+
+def test_rt_wrapper_caches():
+    rt_credentials = RT_GENERIC_CREDS._replace(auth='rt')
+    config = config_mod.Config()
+    rt1 = config.rt_wrapper(rt_credentials, testutil.RTClient)
+    rt2 = config.rt_wrapper(rt_credentials, testutil.RTClient)
+    assert rt1 is rt2
+
+def test_rt_wrapper_caches_by_creds():
+    config = config_mod.Config()
+    rt1 = config.rt_wrapper(RT_GENERIC_CREDS._replace(auth='rt'), testutil.RTClient)
+    rt2 = config.rt_wrapper(None, testutil.RTClient)
+    assert rt1 is not rt2
+
+def test_rt_wrapper_cache_responds_to_external_credential_changes(rt_environ):
+    config = config_mod.Config()
+    rt1 = config.rt_wrapper(None, testutil.RTClient)
+    with update_environ(**rt_environ):
+        rt2 = config.rt_wrapper(None, testutil.RTClient)
+    assert rt1 is not rt2