Reload key cache periodically

Use [default]cache_refresh_minutes configuration parameter to define periods
between cache reloads.  After this number of minutes cache will be reloaded.

lacre/daemon.py

@@ -3,7 +3,6 @@
 import logging
 import lacre
 import lacre.config as conf
-import lacre.keycache as kcache
 import sys
 from aiosmtpd.controller import Controller
 from aiosmtpd.smtp import Envelope
@@ -24,6 +23,7 @@ lacre.init_logging(conf.get_item("logging", "config"))
 LOG = logging.getLogger(__name__)
 
 import lacre.mailgate as gate
+import lacre.keycache as kcache
 
 
 class MailEncryptionProxy:
@@ -48,11 +48,11 @@ class MailEncryptionProxy:
         return RESULT_NOT_IMPLEMENTED
 
 
-def _init_controller(keys: kcache.KeyCache):
+def _init_controller(keys: kcache.KeyCache, tout: float = 2.5):
     proxy = MailEncryptionProxy(keys)
     host, port = conf.daemon_params()
     LOG.info(f"Initialising a mail Controller at {host}:{port}")
-    return Controller(proxy, hostname=host, port=port)
+    return Controller(proxy, hostname=host, port=port, ready_timeout=tout)
 
 
 def _validate_config():
@@ -67,27 +67,26 @@ def _full_param_name(tup):
     return f"[{tup[0]}]{tup[1]}"
 
 
-async def _sleep():
+async def _sleep(minutes, heartbeat_func):
     while True:
-        await asyncio.sleep(5)
+        await asyncio.sleep(minutes * 60)
+        heartbeat_func()
 
 
 def _main():
     _validate_config()
 
+    refresh_min = float(conf.get_item('gpg', 'cache_refresh_minutes', 2))
+
     keys = kcache.KeyCache(conf.get_item('gpg', 'keyhome'))
     keys.load()
     controller = _init_controller(keys)
 
     LOG.info("Starting the daemon...")
-    # starts the controller in a new thread
     controller.start()
 
-    # _this_ thread now continues operation, so it may be used to control key
-    # and certificate cache
-
     try:
-        asyncio.run(_sleep())
+        asyncio.run(_sleep(refresh_min, keys.load))
     except KeyboardInterrupt:
         LOG.info("Finishing...")
 

lacre/keycache.py

@@ -8,6 +8,10 @@ import GnuPG
 LOG = logging.getLogger(__name__)
 
 
+class KeyCacheMisconfiguration(Exception):
+    """Exception used to signal that KeyCache is misconfigured."""
+
+
 class KeyCache:
     """A store for OpenPGP keys.
 
@@ -44,11 +48,15 @@ class KeyCache:
 
     def load(self):
         """Load keyring, replacing any previous contents of the cache."""
+        LOG.debug('Reloading keys...')
+        if self._keyring_dir is None:
+            LOG.error('Keyringn directory not set!')
+            raise KeyCacheMisconfiguration("Keyring directory not configured")
         self.replace_keyring(self._load_keyring_from(self._keyring_dir))
 
     reload = load
 
-    def load_keyring(self, keyhome: str):
+    def load_keyring_from(self, keyhome: str):
         """Add all identities from keyring stored in KEYHOME."""
         self.extend_keyring(self._load_keyring_from(keyhome))
 
@@ -60,7 +68,7 @@ class KeyCache:
         for fingerprint in keys:
             keys[fingerprint] = text.sanitize_case_sense(keys[fingerprint])
 
-        LOG.info(f'Loaded {len(keys)} keys')
+        LOG.info(f'Storing {len(keys)} keys')
         self._keys = keys
 
     def extend_keyring(self, keys: dict):
@@ -68,5 +76,5 @@ class KeyCache:
         for fingerprint in keys:
             keys[fingerprint] = text.sanitize_case_sense(keys[fingerprint])
 
-        LOG.info(f'Loaded {len(keys)} keys')
+        LOG.info(f'Adding {len(keys)} keys')
         self._keys.update(keys)

lacre/mailgate.py

@@ -132,7 +132,7 @@ def _customise_headers(msg_copy):
 def _load_keys():
     """Return a map from a key's fingerprint to email address."""
     keys = kcache.KeyCache()
-    keys.load_keyring(conf.get_item('gpg', 'keyhome'))
+    keys.load_keyring_from(conf.get_item('gpg', 'keyhome'))
     return keys