X-Git-Url: https://osm.etsi.org/gitweb/?a=blobdiff_plain;f=juju%2Futils.py;h=1d1b24ecd647089ebb335a706350fa61dc29a52a;hb=d6348ef405d6e87a4f72e7842ea4376678456283;hp=c0a500c252e6bb1ba494a1737d8e56d722768f4f;hpb=896db9ff2ab6afeb9756948c771bddae942e2723;p=osm%2FN2VC.git

diff --git a/juju/utils.py b/juju/utils.py
index c0a500c..1d1b24e 100644
--- a/juju/utils.py
+++ b/juju/utils.py
@@ -1,5 +1,7 @@
 import asyncio
 import os
+from collections import defaultdict
+from functools import partial
 from pathlib import Path
 
 
@@ -45,3 +47,52 @@ async def read_ssh_key(loop):
 
     '''
     return await loop.run_in_executor(None, _read_ssh_key)
+
+
+class IdQueue:
+    """
+    Wrapper around asyncio.Queue that maintains a separate queue for each ID.
+    """
+    def __init__(self, maxsize=0, *, loop=None):
+        self._queues = defaultdict(partial(asyncio.Queue, maxsize, loop=loop))
+
+    async def get(self, id):
+        value = await self._queues[id].get()
+        del self._queues[id]
+        if isinstance(value, Exception):
+            raise value
+        return value
+
+    async def put(self, id, value):
+        await self._queues[id].put(value)
+
+    async def put_all(self, value):
+        for queue in self._queues.values():
+            await queue.put(value)
+
+
+async def run_with_interrupt(task, event, loop=None):
+    """
+    Awaits a task while allowing it to be interrupted by an `asyncio.Event`.
+
+    If the task finishes without the event becoming set, the results of the
+    task will be returned.  If the event becomes set, the task will be
+    cancelled ``None`` will be returned.
+
+    :param task: Task to run
+    :param event: An `asyncio.Event` which, if set, will interrupt `task`
+        and cause it to be cancelled.
+    :param loop: Optional event loop to use other than the default.
+    """
+    loop = loop or asyncio.get_event_loop()
+    event_task = loop.create_task(event.wait())
+    done, pending = await asyncio.wait([task, event_task],
+                                       loop=loop,
+                                       return_when=asyncio.FIRST_COMPLETED)
+    for f in pending:
+        f.cancel()
+    result = [f.result() for f in done if f is not event_task]
+    if result:
+        return result[0]
+    else:
+        return None