Networks: spawn with asyncio

lxc_net/network.py

@@ -4,6 +4,8 @@ from . import settings
 from . import util
 from .jinja_template import JinjaTemplate
 
+import asyncio
+
 
 class Network(util.LibvirtObject):
     class AlreadyExists(Exception):
@@ -40,6 +42,11 @@ class Network(util.LibvirtObject):
 
         self.lxc_network = self.conn.networkCreateXML(xml)
 
+    async def async_create(self):
+        """ Same as `create`, asyncio-enabled """
+        executor_create = util.run_in_executor(self.create)
+        await executor_create()
+
     def cleanup(self):
         if self.lxc_network:
             self.lxc_network.destroy()

lxc_net/util.py

@@ -5,6 +5,8 @@ import uuid
 
 import subprocess
 import sys
+import asyncio
+import functools
 
 
 class NumberedClass:
@@ -136,3 +138,14 @@ def run_cmd_retry(command, *args, **kwargs):
         print("Command failed. Try again:", file=sys.stderr)
         rc = subprocess.run(command, *args, **kwargs)
     return rc
+
+
+def run_in_executor(f):
+    """ Decorator: transforms a blocking function into an awaitable one """
+
+    @functools.wraps(f)
+    def inner(*args, **kwargs):
+        loop = asyncio.get_running_loop()
+        return loop.run_in_executor(None, functools.partial(f, *args, **kwargs))
+
+    return inner

spawn_network.py

@@ -5,6 +5,7 @@ import sys
 import signal
 import libvirt
 import argparse
+import asyncio
 
 
 def parse_args():
@@ -15,6 +16,18 @@ def parse_args():
     return args
 
 
+async def spawn_network(link):
+    await link.async_create()
+    print(link.name, end="... ")
+    sys.stdout.flush()
+
+
+async def spawn_networks(links):
+    link_tasks = [asyncio.create_task(spawn_network(link)) for link in links]
+    for link_task in link_tasks:
+        await link_task
+
+
 def main():
     args = parse_args()
 
@@ -35,12 +48,7 @@ def main():
 
     print(">> Spawning networks: ", end="")
     sys.stdout.flush()
-    for link in topology.links:
-        if received_sigint:
-            return
-        print(link.name, end="... ")
-        sys.stdout.flush()
-        link.create()
+    asyncio.run(spawn_networks(topology.links))
     print("Done.")
 
     print(">> Spawning containers: ", end="")