-#!/usr/bin/env python
+#!/usr/bin/env python2
-# Copyright (c) 2016 Cisco and/or its affiliates.
+# Copyright (c) 2019 Cisco and/or its affiliates.
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at:
# See the License for the specific language governing permissions and
# limitations under the License.
-"""This script provides simple reservation mechanism to avoid
- simultaneous use of nodes listed in topology file.
- As source of truth is used DUT1 node from the topology file."""
+"""Script managing reservation and un-reservation of testbeds.
+
+This script provides simple reservation mechanism to avoid
+simultaneous use of nodes listed in topology file.
+As source of truth, TG node from the topology file is used.
+"""
import sys
import argparse
-from resources.libraries.python.ssh import SSH
-from yaml import load
+import yaml
+
+from resources.libraries.python.ssh import exec_cmd
+
RESERVATION_DIR = "/tmp/reservation_dir"
+RESERVATION_NODE = "TG"
+
+
+def diag_cmd(node, cmd):
+ """Execute cmd, print cmd and stdout, ignore stderr and rc; return None.
+
+ :param node: Node object as parsed from topology file to execute cmd on.
+ :param cmd: Command to execute.
+ :type ssh: dict
+ :type cmd: str
+ """
+ print('+ {cmd}'.format(cmd=cmd))
+ _, stdout, _ = exec_cmd(node, cmd)
+ print(stdout)
+
def main():
+ """Parse arguments, perform the action, write useful output, propagate RC.
+
+ If the intended action is cancellation, reservation dir is deleted.
+
+ If the intended action is reservation, the list is longer:
+ 1. List contents of reservation dir.
+ 2. List contents of test.url file in the dir.
+ 3. Create reservation dir.
+ 4. Touch file according to -r option.
+ From these 4 steps, 1 and 2 are performed always, their RC ignored.
+ RC of step 3 gives the overall result.
+ If the result is success, step 4 is executed without any output,
+ their RC is ignored.
+
+ The "run tag" as a filename is useful for admins accessing the testbed
+ 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,
help="Topology file")
parser.add_argument("-c", "--cancel", help="Cancel reservation",
action="store_true")
+ parser.add_argument("-r", "--runtag", required=False, default="Unknown",
+ help="Identifier for test run suitable as filename")
args = parser.parse_args()
- topology_file = args.topo
- cancel_reservation = args.cancel
- work_file = open(topology_file)
- topology = load(work_file.read())['nodes']
+ with open(args.topo, "r") as topo_file:
+ topology = yaml.load(topo_file.read())['nodes']
- #we are using DUT1 node because we expect DUT1 to be a linux host
- #we don't use TG because we don't expect TG to be linux only host
+ # Even if TG is not guaranteed to be a Linux host,
+ # we are using it, because testing shows SSH access to DUT
+ # during test affects its performance (bursts of lost packets).
try:
- tg_node = topology["DUT1"]
+ node = topology[RESERVATION_NODE]
except KeyError:
- print "Topology file does not contain 'DUT1' node"
+ print("Topology file does not contain '{node}' node".
+ format(node=RESERVATION_NODE))
return 1
- ssh = SSH()
- ssh.connect(tg_node)
-
- #For system reservation we use mkdir it is an atomic operation and we can
- #store additional data (time, client_ID, ..) within reservation directory
- if cancel_reservation:
- ret, _, err = ssh.exec_command("rm -r {}".format(RESERVATION_DIR))
- else:
- ret, _, err = ssh.exec_command("mkdir {}".format(RESERVATION_DIR))
-
- if ret != 0:
- print("{} unsuccessful:\n{}".
- format(("Cancellation " if cancel_reservation else "Reservation"),
- err))
- return ret
+ # For system reservation we use mkdir it is an atomic operation and we can
+ # store additional data (time, client_ID, ..) within reservation directory.
+ if args.cancel:
+ ret, _, err = exec_cmd(node, "rm -r {dir}".format(dir=RESERVATION_DIR))
+ if ret:
+ print("Cancellation unsuccessful:\n{err}".format(err=err))
+ return ret
+ # Before critical section, output can be outdated already.
+ print("Diagnostic commands:")
+ # -d and * are to supress "total <size>", see https://askubuntu.com/a/61190
+ diag_cmd(node, "ls --full-time -cd '{dir}'/*".format(dir=RESERVATION_DIR))
+ print("Attempting testbed reservation.")
+ # Entering critical section.
+ ret, _, _ = exec_cmd(node, "mkdir '{dir}'".format(dir=RESERVATION_DIR))
+ # Critical section is over.
+ if ret:
+ _, stdo, _ = exec_cmd(node, "ls '{dir}'/*".format(dir=RESERVATION_DIR))
+ print("Testbed already reserved by:\n{stdo}".format(stdo=stdo))
+ return 2
+ # Here the script knows it is the only owner of the testbed.
+ print("Reservation success, writing additional info to reservation dir.")
+ ret, _, err = exec_cmd(
+ node, "touch '{dir}/{runtag}'"\
+ .format(dir=RESERVATION_DIR, runtag=args.runtag))
+ if ret:
+ print("Writing test run info failed, but continuing anyway:\n{err}".
+ format(err=err))
+ return 0
+
if __name__ == "__main__":
sys.exit(main())
Code Review / csit.git / blobdiff