Merge pull request #113 from icgood/transient

Retry SWIM configuration on transient failure

pymap/cluster/swim.py

@@ -2,20 +2,23 @@
 from __future__ import annotations
 
 import asyncio
-from argparse import ArgumentParser
+import logging
+from argparse import ArgumentParser, Namespace
 from collections.abc import Mapping
 from contextlib import AsyncExitStack
 
 from pymap.context import cluster_metadata
 from pymap.interfaces.backend import ServiceInterface
-from swimprotocol.config import ConfigError
+from swimprotocol.config import ConfigError, TransientConfigError
 from swimprotocol.members import Member, Members
 from swimprotocol.status import Status
 from swimprotocol.transport import load_transport
 
 
 __all__ = ['transport_type', 'SwimService']
 
+_log = logging.getLogger(__name__)
+
 #: The :class:`~swimprotocol.transport.Transport` implementation.
 transport_type = load_transport()
 
@@ -42,16 +45,29 @@ def _local_update(self, members: Members,
                       metadata: Mapping[str, bytes]) -> None:
         members.update(members.local, new_metadata=metadata)
 
-    async def start(self, stack: AsyncExitStack) -> None:
-        args = self.config.args
-        try:
-            config = transport_type.config_type.from_args(args)
-        except ConfigError:
-            return  # do not run SWIM if not configured properly
+    async def _start(self, args: Namespace, stack: AsyncExitStack) -> None:
+        while True:
+            try:
+                config = transport_type.config_type.from_args(args)
+            except TransientConfigError as exc:
+                _log.debug('SWIM configuration failure: %s', exc)
+                await asyncio.sleep(exc.wait_hint)
+            except ConfigError:
+                return  # do not run SWIM if not configured properly
+            else:
+                break
+
         transport = transport_type(config)
         members = Members(config)
         cluster_metadata.get().listen(self._local_update, members)
         stack.enter_context(members.listener.on_notify(self._remote_update))
         worker = await stack.enter_async_context(transport.enter(members))
         task = asyncio.create_task(worker.run())
         stack.callback(task.cancel)
+
+    async def start(self, stack: AsyncExitStack) -> None:
+        args = self.config.args
+        swim_stack = AsyncExitStack()
+        await stack.enter_async_context(swim_stack)
+        task = asyncio.create_task(self._start(args, swim_stack))
+        stack.callback(task.cancel)

setup.py

@@ -28,7 +28,7 @@
     license = f.read()
 
 setup(name='pymap',
-      version='0.24.4',
+      version='0.24.5',
       author='Ian Good',
       author_email='ian@icgood.net',
       description='Lightweight, asynchronous IMAP serving in Python.',
@@ -56,7 +56,7 @@
           'macaroon': ['pymacaroons'],
           'redis': ['aioredis ~= 1.3.1', 'msgpack ~= 1.0'],
           'sieve': ['sievelib'],
-          'swim': ['swim-protocol ~= 0.3.5'],
+          'swim': ['swim-protocol ~= 0.3.6'],
           'systemd': ['systemd-python'],
           'optional': ['hiredis', 'passlib', 'pid']},
       entry_points={