X-Git-Url: https://gerrit.fd.io/r/gitweb?a=blobdiff_plain;f=resources%2Ftools%2Fscripts%2Ftopo_reservation.py;h=77d84efebadcdfd8645de9b77942db884c498b6d;hb=4929e57e9c8d721000adcbdf2bcbe0dc6952a831;hp=bf31918c7308abc8d1cff38840ddf624d8fa753d;hpb=e4091a25520e8cf1c62254df74b7ccf57f2ce1c7;p=csit.git

diff --git a/resources/tools/scripts/topo_reservation.py b/resources/tools/scripts/topo_reservation.py
index bf31918c73..77d84efeba 100755
--- 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 python2
 
-# Copyright (c) 2018 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:
@@ -22,48 +22,105 @@ 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"
 
+
+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
+    _, 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']
 
     # 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"]
+        tgn = topology["TG"]
     except KeyError:
         print "Topology file does not contain 'TG' 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
+    if args.cancel:
+        ret, _, err = exec_cmd(tgn, "rm -r {}".format(RESERVATION_DIR))
+        if ret:
+            print "Cancellation unsuccessful:\n{}".format(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(tgn, "ls --full-time -cd '{dir}'/*".format(dir=RESERVATION_DIR))
+    print("Attempting reservation.")
+    # Entering critical section.
+    ret, _, err = exec_cmd(tgn, "mkdir '{dir}'".format(dir=RESERVATION_DIR))
+    # Critical section is over.
+    if 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.")
+    ret2, _, err = exec_cmd(
+        tgn, "touch '{dir}/{runtag}'"\
+        .format(dir=RESERVATION_DIR, runtag=args.runtag))
+    if ret2:
+        print("Writing test run info failed, but continuing anyway:\n{}".format(
+            err))
+    return 0
+
 
 if __name__ == "__main__":
     sys.exit(main())