[PATCH] Controller: wait for device initialization

[Ondrej Lichtner]

From: Ondrej Lichtner <olichtne(a)redhat.com&gt;

After creating all the soft interfaces specified in the recipe, the
Controller will now wait until the associated Device object on the Slave
is initialized - this means waiting until there are no more devices left
in the _tmp_mapping dictionary of InterfaceManager.

To do this we introduced a new NetTestSlave method - wait_interface_init
that only returns after the InterfaceManager is ready.

This method is also called every time you create a device from inside a
python task.

This should avoid potential race conditions that we've experienced.

Signed-off-by: Ondrej Lichtner <olichtne(a)redhat.com&gt;
Tested-by: Jiri Pirko <jiri(a)mellanox.com&gt;
---
 lnst/Controller/Machine.py           |  3 +++
 lnst/Controller/NetTestController.py |  2 ++
 lnst/Controller/Task.py              |  3 +++
 lnst/Slave/InterfaceManager.py       | 12 ++++++++++++
 lnst/Slave/NetTestSlave.py           |  4 ++++
 5 files changed, 24 insertions(+)

diff --git a/lnst/Controller/Machine.py b/lnst/Controller/Machine.py
index d0e5b1b..755a2dd 100644
--- a/lnst/Controller/Machine.py
+++ b/lnst/Controller/Machine.py
@@ -500,6 +500,9 @@ class Machine(object):
         self._namespaces = []
         return True
 
+    def wait_interface_init(self):
+        return self._rpc_call("wait_interface_init")
+
 class Interface(object):
     """ Abstraction of a test network interface on a slave machine
 
diff --git a/lnst/Controller/NetTestController.py b/lnst/Controller/NetTestController.py
index 04aa473..1e90688 100644
--- a/lnst/Controller/NetTestController.py
+++ b/lnst/Controller/NetTestController.py
@@ -223,6 +223,8 @@ class NetTestController:
             for iface in ifaces:
                 iface.up()
 
+            m.wait_interface_init()
+
     def provision_machines(self):
         sp = self._slave_pool
         machines = self._machines
diff --git a/lnst/Controller/Task.py b/lnst/Controller/Task.py
index e354180..9aac8c4 100644
--- a/lnst/Controller/Task.py
+++ b/lnst/Controller/Task.py
@@ -404,6 +404,9 @@ class HostAPI(object):
 
         interface.configure()
         interface.up()
+
+        self._m.wait_interface_init()
+
         return iface
 
     def _remove_iface(self, iface):
diff --git a/lnst/Slave/InterfaceManager.py b/lnst/Slave/InterfaceManager.py
index dfc2d10..144f5a7 100644
--- a/lnst/Slave/InterfaceManager.py
+++ b/lnst/Slave/InterfaceManager.py
@@ -13,11 +13,13 @@ olichtne(a)redhat.com (Ondrej Lichtner)
 """
 
 import re
+import select
 from lnst.Slave.NetConfigDevice import NetConfigDevice
 from lnst.Slave.NetConfigCommon import get_option
 from lnst.Common.NetUtils import normalize_hwaddr
 from lnst.Common.NetUtils import scan_netdevs
 from lnst.Common.ExecCmd import exec_cmd
+from lnst.Common.ConnectionHandler import recv_data
 from pyroute2 import IPRSocket
 try:
     from pyroute2.netlink.iproute import RTM_NEWLINK
@@ -210,6 +212,16 @@ class InterfaceManager(object):
         self._tmp_mapping[if_id2] = device2
         return name1, name2
 
+    def wait_interface_init(self):
+        while len(self._tmp_mapping) > 0:
+            rl, wl, xl = select.select([self._nl_socket], [], [], 1)
+
+            if len(rl) == 0:
+                continue
+
+            msgs = recv_data(self._nl_socket)["data"]
+            self.handle_netlink_msgs(msgs)
+
     def _is_name_used(self, name):
         for device in self._devices.itervalues():
             if name == device.get_name():
diff --git a/lnst/Slave/NetTestSlave.py b/lnst/Slave/NetTestSlave.py
index 12b3381..5569f07 100644
--- a/lnst/Slave/NetTestSlave.py
+++ b/lnst/Slave/NetTestSlave.py
@@ -763,6 +763,10 @@ class SlaveMethods:
             return False
         return True
 
+    def wait_interface_init(self):
+        self._if_manager.wait_interface_init()
+        return True
+
 class ServerHandler(ConnectionHandler):
     def __init__(self, addr):
         super(ServerHandler, self).__init__()
-- 
2.7.0