Skip bad testbeds in reservation

Previously, ssh-inaccesible testbeds
were handled the same way as reserved,
never ending the wait loop.

With this, if no testbed is accessible,
the job fails early.

Change-Id: I01bc79094fe0232a47d795e53e3daa52e8742bac
Signed-off-by: Vratko Polak <vrpolak@cisco.com>

1 files changed, 12 insertions, 3 deletions

diff --git a/resources/tools/scripts/topo_reservation.py b/resources/tools/scripts/topo_reservation.py
index a04709b2d5..9f26677f42 100755
--- a/resources/tools/scripts/topo_reservation.py
+++ b/resources/tools/scripts/topo_reservation.py
@@ -74,6 +74,15 @@ def main():
     via a graphical terminal, which does not allow copying of text,
     as they need less keypresses to identify the test run holding the testbed.
     Also, the listing shows timestamps, which is useful for both audiences.
+
+    This all assumes the target system accepts ssh connections.
+    If it does not, the caller probably wants to stop trying
+    to reserve this system. Therefore this script can return 3 different codes.
+    Return code 0 means the reservation was successful.
+    Return code 1 means the system is inaccessible (or similarly unsuitable).
+    Return code 2 means the system is accessible, but already reserved.
+    The reason unsuitable systems return 1 is because that is also the value
+    Python returns on encountering and unexcepted exception.
     """
     parser = argparse.ArgumentParser()
     parser.add_argument("-t", "--topo", required=True,
@@ -117,8 +126,8 @@ def main():
     ret, _, err = exec_cmd(tgn, "mkdir '{dir}'".format(dir=RESERVATION_DIR))
     # Critical section is over.
     if ret:
-        print "Reservation unsuccessful:\n{}".format(err)
-        return ret
+        print "Already reserved by another job:\n{}".format(err)
+        return 2
     # Here the script knows it is the only owner of the testbed.
     print "Success, writing test run info to reservation dir."
     # TODO: Add optional argument to exec_cmd_no_error to print message
@@ -129,7 +138,7 @@ def main():
     if ret2:
         print "Writing test run info failed, but continuing anyway:\n{}".format(
             err)
-    return ret
+    return 0
 
 
 if __name__ == "__main__":