Shield internal block procedures from cancellation

due to connection close() (that the Monitor triggers) because of any
connection issues on the underlying websocket.

Author: cderici

juju/jasyncio.py

@@ -21,7 +21,7 @@
     gather, sleep, wait_for, create_subprocess_exec, subprocess, \
     wait, FIRST_COMPLETED, Lock, as_completed, new_event_loop, \
     get_event_loop_policy, CancelledError, get_running_loop, \
-    create_task, ALL_COMPLETED, all_tasks, current_task     # noqa
+    create_task, ALL_COMPLETED, all_tasks, current_task, shield     # noqa
 
 
 def create_task_with_handler(coro, task_name, logger=ROOT_LOGGER):

juju/utils.py

@@ -128,7 +128,7 @@ async def block_until(*conditions, timeout=None, wait_period=0.5):
     async def _block():
         while not all(c() for c in conditions):
             await jasyncio.sleep(wait_period)
-    await jasyncio.wait_for(_block(), timeout)
+    await jasyncio.shield(jasyncio.wait_for(_block(), timeout))
 
 
 async def block_until_with_coroutine(condition_coroutine, timeout=None, wait_period=0.5):
@@ -139,7 +139,7 @@ async def block_until_with_coroutine(condition_coroutine, timeout=None, wait_per
     async def _block():
         while not await condition_coroutine():
             await jasyncio.sleep(wait_period)
-    await jasyncio.wait_for(_block(), timeout=timeout)
+    await jasyncio.shield(jasyncio.wait_for(_block(), timeout=timeout))
 
 
 async def wait_for_bundle(model, bundle, **kwargs):