Update VPP_STABLE_VER files

[csit.git] / resources / tools / scripts / topo_reservation.py

diff --git a/resources/tools/scripts/topo_reservation.py b/resources/tools/scripts/topo_reservation.py
index bf31918..f2d18bc 100755 (executable)
--- a/resources/tools/scripts/topo_reservation.py
+++ b/resources/tools/scripts/topo_reservation.py
@@ -1,6 +1,6 @@
-#!/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:
 # 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:


@@ -20,50 +20,114 @@ simultaneous use of nodes listed in topology file.
 As source of truth, TG node from the topology file is used.
 """
 
 As source of truth, TG node from the topology file is used.
 """
 

-import sys

 import argparse
 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():
 
 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 = 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()
     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:
 
     # 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:
     except KeyError:

-        print "Topology file does not contain 'TG' node"
+        print(f"Topology file does not contain '{RESERVATION_NODE}' node")

         return 1
 
         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.
     # 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:
     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())
     sys.exit(main())