-#!/usr/bin/env python
+#!/usr/bin/env python3
-# Copyright (c) 2018 Cisco and/or its affiliates.
+# Copyright (c) 2022 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:
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 sys
+import yaml
+
+from resources.libraries.python.ssh import exec_cmd
+
+
+RESERVATION_DIR = u"/tmp/reservation_dir"
+RESERVATION_NODE = u"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 node: dict
+ :type cmd: str
+ """
+ print(f"+ {cmd}")
+ _, stdout, _ = exec_cmd(node, cmd)
+ print(stdout)
-RESERVATION_DIR = "/tmp/reservation_dir"
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(u"-t", u"--topo", required=True, help=u"Topology file")
+ parser.add_argument(
+ u"-c", u"--cancel", help=u"Cancel reservation", action=u"store_true"
+ )
+ parser.add_argument(
+ u"-r", u"--runtag", required=False, default=u"Unknown",
+ help=u"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, u"rt") as topo_file:
+ topology = yaml.safe_load(topo_file.read())[u"nodes"]
# 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["TG"]
+ node = topology[RESERVATION_NODE]
except KeyError:
- print "Topology file does not contain 'TG' node"
+ print(f"Topology file does not contain '{RESERVATION_NODE}' 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 args.cancel:
+ ret, _, err = exec_cmd(node, f"rm -r {RESERVATION_DIR}")
+ # If connection is refused, ret==None.
+ if ret != 0:
+ print(f"Cancellation unsuccessful:\n{err!r}")
+ return 1
+ return 0
+ # Before critical section, output can be outdated already.
+ print(u"Diagnostic commands:")
+ # -d and * are to suppress "total <size>", see https://askubuntu.com/a/61190
+ diag_cmd(node, f"ls --full-time -cd '{RESERVATION_DIR}'/*")
+ print(u"Attempting testbed reservation.")
+ # Entering critical section.
+ ret, _, _ = exec_cmd(node, f"mkdir '{RESERVATION_DIR}'")
+ # Critical section is over.
+ if ret is None:
+ print(u"Failed to connect to testbed.")
+ return 1
if ret != 0:
- print("{} unsuccessful:\n{}".
- format(("Cancellation " if cancel_reservation else "Reservation"),
- err))
- return ret
+ _, stdo, _ = exec_cmd(node, f"ls '{RESERVATION_DIR}'/*")
+ print(f"Testbed already reserved by:\n{stdo}")
+ return 2
+ # Here the script knows it is the only owner of the testbed.
+ print(u"Reservation success, writing additional info to reservation dir.")
+ ret, _, err = exec_cmd(
+ node, f"touch '{RESERVATION_DIR}/{args.runtag}'")
+ if ret != 0:
+ print(f"Writing test run info failed, but continuing anyway:\n{err!r}")
+ return 0
+
-if __name__ == "__main__":
+if __name__ == u"__main__":
sys.exit(main())
Code Review / csit.git / blobdiff