Add timeout fundamentals for daemon client communication

Author: cottsay

ros2cli/ros2cli/node/daemon.py

@@ -27,15 +27,17 @@
 from ros2cli.helpers import wait_for
 
 from ros2cli.xmlrpc.client import ServerProxy
+from ros2cli.xmlrpc.client import TimeoutTransport
 
 
 class DaemonNode:
 
-    def __init__(self, args):
+    def __init__(self, args, *, timeout=None):
         self._args = args
         self._proxy = ServerProxy(
             daemon.get_xmlrpc_server_url(),
-            allow_none=True)
+            allow_none=True,
+            transport=TimeoutTransport(timeout=timeout))
         self._methods = []
 
     @property
@@ -65,13 +67,16 @@ def __exit__(self, exc_type, exc_value, traceback):
         self._proxy.__exit__(exc_type, exc_value, traceback)
 
 
-def is_daemon_running(args):
+def is_daemon_running(args, timeout=None):
     """
     Check if the daemon node is running.
 
     :param args: `DaemonNode` arguments namespace.
+    :param timeout: option duration, in seconds, to wait
+      for the daemon node to respond. If it is not given,
+      the global default timeout setting is used.
     """
-    with DaemonNode(args) as node:
+    with DaemonNode(args, timeout=timeout) as node:
         return node.connected
 
 

ros2cli/ros2cli/xmlrpc/client.py

@@ -15,9 +15,24 @@
 # Alias xmlrpc.client module objects to ensure client code uses ros2cli.xmlrpc
 from xmlrpc.client import ProtocolError
 from xmlrpc.client import ServerProxy
+from xmlrpc.client import Transport
 
 
 __all__ = [
     'ProtocolError',
-    'ServerProxy'
+    'ServerProxy',
+    'TimeoutTransport',
 ]
+
+
+class TimeoutTransport(Transport):
+
+    def __init__(self, *args, timeout=None, **kwargs):
+        super().__init__(*args, **kwargs)
+        self._timeout = timeout
+
+    def make_connection(self, *args, **kwargs):
+        connection = super().make_connection(*args, **kwargs)
+        if self._timeout is not None:
+            connection.timeout = self._timeout
+        return connection

ros2cli/test/test_strategy.py

@@ -24,14 +24,14 @@
 
 @pytest.fixture
 def enforce_no_daemon_is_running():
-    if is_daemon_running(args=[]):
+    if is_daemon_running(args=[], timeout=5.0):
         assert shutdown_daemon(args=[], timeout=5.0)
     yield
 
 
 @pytest.fixture
 def enforce_daemon_is_running():
-    if not is_daemon_running(args=[]):
+    if not is_daemon_running(args=[], timeout=5.0):
         assert spawn_daemon(args=[], timeout=5.0)
     yield