dhcp client: allow trying once to get a lease then exiting, like dhcl…

…ient -1

pyroute2/dhcp/cli.py

@@ -50,10 +50,11 @@ def get_psr() -> ArgumentParser:
     )
     psr.add_argument(
         '-x',
-        '--exit-on-lease',
-        help='Exit as soon as getting a lease.',
-        default=False,
-        action='store_true',
+        '--exit-on-timeout',
+        metavar='N',
+        help='Wait for max N seconds for a lease, '
+        'exit if none could be obtained.',
+        type=int,
     )
     psr.add_argument(
         '--log-level',
@@ -91,21 +92,25 @@ async def main():
     # Open the socket, read existing lease, etc
     async with AsyncDHCPClient(cfg) as acli:
         # Bootstrap the client by sending a DISCOVER or a REQUEST
-        await acli.bootstrap()
-        if args.exit_on_lease:
-            # Wait until we're bound once, then exit
-            await acli.wait_for_state(State.BOUND)
-        else:
-            # Wait until the client is stopped otherwise
+        try:
+            await acli.bootstrap()
+            if args.exit_on_timeout:
+                # Wait a bit for a lease, and exit if we have none
+                try:
+                    await acli.wait_for_state(
+                        State.BOUND, timeout=args.exit_on_timeout
+                    )
+                except TimeoutError as err:
+                    psr.error(str(err))
+            # Wait until the client is stopped
             await acli.wait_for_state(State.OFF)
+        except (asyncio.CancelledError, KeyboardInterrupt):
+            pass
 
 
 def run():
     # for the setup.cfg entrypoint
-    try:
-        asyncio.run(main())
-    except KeyboardInterrupt:
-        pass
+    asyncio.run(main())
 
 
 if __name__ == '__main__':

pyroute2/dhcp/client.py

@@ -291,6 +291,7 @@ async def _send_forever(self) -> None:
                     floor(time() - self.last_state_change), 0xFFFF
                 )
                 msg_to_send.dhcp['xid'] = self.xid.for_state(self.state)
+                # TODO: don't send aynthing else than RELEASEs when stopping
                 LOG.info('Sending %s', msg_to_send)
                 await self._sock.put(msg_to_send)
 

tests/test_linux/test_dhcp/test_cli.py

@@ -1,5 +1,6 @@
 import asyncio
 import json
+import signal
 from ipaddress import IPv4Address
 
 import pytest
@@ -18,10 +19,14 @@ async def test_client_console(dnsmasq: DnsmasqFixture, veth_pair: VethPair):
         veth_pair.client,
         '--lease-type',
         'pyroute2.dhcp.leases.JSONStdoutLease',
-        '--exit-on-lease',
+        '--exit-on-timeout=5',
         '--log-level=DEBUG',
         stdout=asyncio.subprocess.PIPE,
     )
+
+    asyncio.get_running_loop().call_later(
+        2, process.send_signal, signal.SIGINT
+    )
     try:
         stdout, _ = await asyncio.wait_for(process.communicate(), timeout=5)
     except TimeoutError: