From cf6a784d4e78ef77630e19cc73955ad60c244ee6 Mon Sep 17 00:00:00 2001
From: Andrew Jeffery <andrew@aj.id.au>
Date: Thu, 12 Oct 2017 14:47:43 +1030
Subject: pytools: obmcutil: Optionally wait for standby before getting objects

If the user passes --wait, try to immediately get the object but wait
until we reach standby before trying again if the first attempt fails.

The correct strategy is probably to look for registration of names on
the bus, but this ghetto approach also works.

Change-Id: I71b6f5d4fcf5841510da6f9877726b875b019d51
Signed-off-by: Andrew Jeffery <andrew@aj.id.au>
---
 pytools/obmcutil | 43 ++++++++++++++++++++++++++++++++++++++++++-
 1 file changed, 42 insertions(+), 1 deletion(-)

(limited to 'pytools')

diff --git a/pytools/obmcutil b/pytools/obmcutil
index 2661da0..e2b422a 100644
--- a/pytools/obmcutil
+++ b/pytools/obmcutil
@@ -114,11 +114,37 @@ def run_set_property(dbus_bus, dbus_iface, descriptor, args):
 
     return property_listener.success
 
+def get_dbus_obj(dbus_bus, bus, obj, args):
+    if not args.wait:
+        return dbus_bus.get_object(bus, obj)
+
+    mainloop = gobject.MainLoop()
+
+    def property_listener(job, path, unit, state):
+        if 'obmc-standby.target' == unit:
+            mainloop.quit()
+
+    sig_match = dbus_bus.add_signal_receiver(property_listener, "JobRemoved")
+    try:
+        return dbus_bus.get_object(bus, obj)
+    except dbus.exceptions.DBusException as e:
+        if args.verbose:
+            pid = Popen(["/bin/journalctl", "-f", "--no-pager"]).pid
+
+        mainloop.run()
+
+        if args.verbose:
+            os.kill(pid, signal.SIGTERM)
+    finally:
+        sig_match.remove()
+
+    return dbus_bus.get_object(bus, obj)
+
 def run_one_command(dbus_bus, descriptor, args):
     bus = descriptor['bus_name']
     obj = descriptor['object_name']
     iface = descriptor['interface_name']
-    dbus_obj = dbus_bus.get_object(bus, obj)
+    dbus_obj = get_dbus_obj(dbus_bus, bus, obj, args)
     result = None
 
     if 'property' in descriptor:
@@ -167,8 +193,23 @@ def main():
     args = parser.parse_args()
 
     dbus_bus = dbus.SystemBus()
+
+    # The only way to get a sensible backtrace with python 2 without stupid
+    # hoops is to let the uncaught exception handler do the work for you.
+    # Catching and binding an exception appears to overwrite the stack trace at
+    # the point of bind.
+    #
+    # So, if we're in verbose mode, don't try to catch the DBus exception. That
+    # way we can understand where it originated.
+    if args.verbose:
+        return run_all_commands(dbus_bus, descriptors[args.recipe], args)
+
+    # Otherwise, we don't care about the traceback. Just catch it and print the
+    # error message.
     try:
         return run_all_commands(dbus_bus, descriptors[args.recipe], args)
+    except dbus.exceptions.DBusException as e:
+        print >> sys.stderr, "DBus error occurred: {}".format(e.get_dbus_message())
     finally:
         dbus_bus.close()
 
-- 
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