examples: Convert to ArgumentParser

Replace getopt() and hand-rolled-parser with argparse.ArgumentParser.

Fix wrong header comments copy-pasted from domstart.py

Signed-off-by: Philipp Hahn <hahn@univention.de>

12 files changed, 143 insertions, 236 deletions

diff --git a/examples/consolecallback.py b/examples/consolecallback.py
index e8820f7..9947f75 100644
--- a/examples/consolecallback.py
+++ b/examples/consolecallback.py
@@ -2,6 +2,7 @@
 # consolecallback - provide a persistent console that survives guest reboots
 
 import sys, os, logging, libvirt, tty, termios, atexit
+from argparse import ArgumentParser
 from typing import Optional  # noqa F401
 
 def reset_term() -> None:
@@ -64,18 +65,15 @@ def lifecycle_callback(connection: libvirt.virConnect, domain: libvirt.virDomain
                  console.uuid, console.state[0], console.state[1])
 
 # main
-if len(sys.argv) != 3:
-    print("Usage:", sys.argv[0], "URI UUID")
-    print("for example:", sys.argv[0], "'qemu:///system' '32ad945f-7e78-c33a-e96d-39f25e025d81'")
-    sys.exit(1)
-
-uri = sys.argv[1]
-uuid = sys.argv[2]
+parser = ArgumentParser(epilog="Example: %(prog)s 'qemu:///system' '32ad945f-7e78-c33a-e96d-39f25e025d81'")
+parser.add_argument("uri")
+parser.add_argument("uuid")
+args = parser.parse_args()
 
 print("Escape character is ^]")
 logging.basicConfig(filename='msg.log', level=logging.DEBUG)
-logging.info("URI: %s", uri)
-logging.info("UUID: %s", uuid)
+logging.info("URI: %s", args.uri)
+logging.info("UUID: %s", args.uuid)
 
 libvirt.virEventRegisterDefaultImpl()
 libvirt.registerErrorHandler(error_handler, None)
@@ -84,7 +82,7 @@ atexit.register(reset_term)
 attrs = termios.tcgetattr(0)
 tty.setraw(0)
 
-console = Console(uri, uuid)
+console = Console(args.uri, args.uuid)
 console.stdin_watch = libvirt.virEventAddHandle(0, libvirt.VIR_EVENT_HANDLE_READABLE, stdin_callback, console)
 
 while check_console(console):
diff --git a/examples/dhcpleases.py b/examples/dhcpleases.py
index 82ba002..d023e4d 100755
--- a/examples/dhcpleases.py
+++ b/examples/dhcpleases.py
@@ -1,37 +1,29 @@
 #!/usr/bin/env python3
-# netdhcpleases - print leases info for given virtual network
+"""
+Print leases info for a given virtual network
+"""
 
 import libvirt
 import sys
 import time
+from argparse import ArgumentParser
 
-def usage() -> None:
-    print("Usage: %s [URI] NETWORK" % sys.argv[0])
-    print("        Print leases info for a given virtual network")
 
-uri = None
-network = None
-args = len(sys.argv)
-
-if args == 2:
-    network = sys.argv[1]
-elif args == 3:
-    uri = sys.argv[1]
-    network = sys.argv[2]
-else:
-    usage()
-    sys.exit(2)
+parser = ArgumentParser(description=__doc__)
+parser.add_argument("uri", nargs="?", default=None)
+parser.add_argument("network")
+args = parser.parse_args()
 
 try:
-    conn = libvirt.open(uri)
+    conn = libvirt.open(args.uri)
 except libvirt.libvirtError:
     print("Unable to open connection to libvirt")
     sys.exit(1)
 
 try:
-    net = conn.networkLookupByName(network)
+    net = conn.networkLookupByName(args.network)
 except libvirt.libvirtError:
-    print("Network %s not found" % network)
+    print("Network %s not found" % args.network)
     sys.exit(0)
 
 leases = net.DHCPLeases()
diff --git a/examples/dominfo.py b/examples/dominfo.py
index 7e8a9a1..bb00b59 100755
--- a/examples/dominfo.py
+++ b/examples/dominfo.py
@@ -1,16 +1,21 @@
 #!/usr/bin/env python3
-# dominfo - print some information about a domain
+"""
+Print information about the domain DOMAIN
+"""
 
 import libvirt
 import sys
 import os
 import libxml2
 import pdb
+from argparse import ArgumentParser
 from typing import Any
 
-def usage() -> None:
-   print('Usage: %s DOMAIN' % sys.argv[0])
-   print('       Print information about the domain DOMAIN')
+
+parser = ArgumentParser(description=__doc__)
+parser.add_argument("domain")
+args = parser.parse_args()
+
 
 def print_section(title: str) -> None:
     print("\n%s" % title)
@@ -28,11 +33,6 @@ def print_xml(key: str, ctx, path: str) -> str:
     print_entry(key, value)
     return value
 
-if len(sys.argv) != 2:
-    usage()
-    sys.exit(2)
-
-name = sys.argv[1]
 
 # Connect to libvirt
 try:
@@ -42,10 +42,10 @@ except libvirt.libvirtError:
     sys.exit(1)
 
 try:
-    dom = conn.lookupByName(name)
+    dom = conn.lookupByName(args.domain)
     # Annoyiingly, libvirt prints its own error message here
 except libvirt.libvirtError:
-    print("Domain %s is not running" % name)
+    print("Domain %s is not running" % args.domain)
     sys.exit(0)
 
 info = dom.info()
diff --git a/examples/domipaddrs.py b/examples/domipaddrs.py
index 611916f..2b9f276 100755
--- a/examples/domipaddrs.py
+++ b/examples/domipaddrs.py
@@ -1,8 +1,11 @@
 #!/usr/bin/env python3
-# domipaddrs - print domain interfaces along with their MAC and IP addresses
+"""
+Print domain interfaces along with their MAC and IP addresses
+"""
 
 import libvirt
 import sys
+from argparse import ArgumentParser
 
 IPTYPE = {
     libvirt.VIR_IP_ADDR_TYPE_IPV4: "ipv4",
@@ -33,29 +36,20 @@ def print_dom_ifaces(dom: libvirt.virDomain) -> None:
 
 
 if __name__ == "__main__":
-    uri = None
-    name = None
-    args = len(sys.argv)
-
-    if args == 2:
-        name = sys.argv[1]
-    elif args == 3:
-        uri = sys.argv[1]
-        name = sys.argv[2]
-    else:
-        print("Usage: %s [URI] DOMAIN" % sys.argv[0])
-        print("        Print domain interfaces along with their MAC and IP addresses")
-        sys.exit(2)
+    parser = ArgumentParser(description=__doc__)
+    parser.add_argument("uri", nargs="?", default=None)
+    parser.add_argument("domain")
+    args = parser.parse_args()
 
     try:
-        conn = libvirt.open(uri)
+        conn = libvirt.open(args.uri)
     except libvirt.libvirtError:
         raise SystemExit("Unable to open connection to libvirt")
 
     try:
-        dom = conn.lookupByName(name)
+        dom = conn.lookupByName(args.domain)
     except libvirt.libvirtError:
-        print("Domain %s not found" % name)
+        print("Domain %s not found" % args.domain)
         sys.exit(0)
 
     print_dom_ifaces(dom)
diff --git a/examples/domrestore.py b/examples/domrestore.py
index 3c6b410..c89405d 100755
--- a/examples/domrestore.py
+++ b/examples/domrestore.py
@@ -1,24 +1,22 @@
 #!/usr/bin/env python3
-# domstart - make sure a given domU is running, if not start it
+"""
+Restore all the domains contained in DIR.
+It is assumed that all files in DIR are images of domU's previously created with save.
+"""
 
 import libvirt
 import sys
 import os
 import libxml2
 import pdb
+from argparse import ArgumentParser
 
-def usage() -> None:
-   print('Usage: %s DIR' % sys.argv[0])
-   print('       Restore all the domains contained in DIR')
-   print('       It is assumed that all files in DIR are')
-   print('       images of domU\'s previously created with save')
 
-if len(sys.argv) != 2:
-    usage()
-    sys.exit(2)
+parser = ArgumentParser(description=__doc__)
+parser.add_argument("dir")
+args = parser.parse_args()
 
-dir = sys.argv[1]
-imgs = os.listdir(dir)
+imgs = os.listdir(args.dir)
 
 try:
     conn = libvirt.open(None)
@@ -27,7 +25,7 @@ except libvirt.libvirtError:
     sys.exit(1)
 
 for img in imgs:
-    file = os.path.join(dir, img)
+    file = os.path.join(args.dir, img)
     print("Restoring %s ... " % img)
     ret = conn.restore(file)
     if ret == 0:
diff --git a/examples/domsave.py b/examples/domsave.py
index 2a85554..2f140a2 100755
--- a/examples/domsave.py
+++ b/examples/domsave.py
@@ -1,22 +1,20 @@
 #!/usr/bin/env python3
-# domstart - make sure a given domU is running, if not start it
+"""
+Save all currently running domU's into DIR.
+DIR must exist and be writable by this process.
+"""
 
 import libvirt
 import sys
 import os
 import libxml2
 import pdb
+from argparse import ArgumentParser
 
-def usage() -> None:
-   print('Usage: %s DIR' % sys.argv[0])
-   print('       Save all currently running domU\'s into DIR')
-   print('       DIR must exist and be writable by this process')
 
-if len(sys.argv) != 2:
-    usage()
-    sys.exit(2)
-
-dir = sys.argv[1]
+parser = ArgumentParser(description=__doc__)
+parser.add_argument("dir")
+args = parser.parse_args()
 
 try:
     conn = libvirt.open(None)
@@ -30,7 +28,7 @@ for id in doms:
         continue
     dom = conn.lookupByID(id)
     print("Saving %s[%d] ... " % (dom.name(), id))
-    path = os.path.join(dir, dom.name())
+    path = os.path.join(args.dir, dom.name())
     ret = dom.save(path)
     if ret == 0:
         print("done")
diff --git a/examples/domstart.py b/examples/domstart.py
index cd6de59..446a793 100755
--- a/examples/domstart.py
+++ b/examples/domstart.py
@@ -1,11 +1,15 @@
 #!/usr/bin/env python3
-# domstart - make sure a given domU is running, if not start it
+"""
+Check that the domain described by DOMAIN.XML is running.
+If the domain is not running, create it.
+"""
 
 import libvirt
 import sys
 import os
 import libxml2
 import pdb
+from argparse import ArgumentParser
 from typing import Tuple
 
 # Parse the XML description of domU from FNAME
@@ -20,18 +24,12 @@ def read_domain(fname: str) -> Tuple[str, str]:
     name = doc.xpathNewContext().xpathEval("/domain/name")[0].content
     return (name, xmldesc)
 
-def usage() -> None:
-   print('Usage: %s domain.xml' % sys.argv[0])
-   print('       Check that the domain described by DOMAIN.XML is running')
-   print('       If the domain is not running, create it')
-   print('       DOMAIN.XML must be a XML description of the domain')
-   print('       in libvirt\'s XML format')
 
-if len(sys.argv) != 2:
-    usage()
-    sys.exit(2)
+parser = ArgumentParser(description=__doc__)
+parser.add_argument("file", metavar="DOMAIN.XML", help="XML configuration of the domain in libvirt's XML format")
+args = parser.parse_args()
 
-(name, xmldesc) = read_domain(sys.argv[1])
+(name, xmldesc) = read_domain(args.file)
 
 try:
     conn = libvirt.open(None)
diff --git a/examples/esxlist.py b/examples/esxlist.py
index 0d49f32..59c8210 100755
--- a/examples/esxlist.py
+++ b/examples/esxlist.py
@@ -1,20 +1,18 @@
 #!/usr/bin/env python3
-# esxlist - list active domains of an ESX host and print some info.
-#           also demonstrates how to use the libvirt.openAuth() method
+"""
+List active domains of an ESX host and print some info.
+"""
+# also demonstrates how to use the libvirt.openAuth() method
 
 import libvirt
 import sys
 import os
 import libxml2
 import getpass
+from argparse import ArgumentParser
 from typing import Any, List
 
 
-def usage() -> None:
-    print("Usage: %s HOSTNAME" % sys.argv[0])
-    print("       List active domains of HOSTNAME and print some info")
-
-
 # This is the callback method passed to libvirt.openAuth() (see below).
 #
 # The credentials argument is a list of credentials that libvirt (actually
@@ -73,15 +71,12 @@ def print_xml(key: str, ctx, path: str) -> str:
     return value
 
 
-if len(sys.argv) != 2:
-    usage()
-    sys.exit(2)
-
-
-hostname = sys.argv[1]
+parser = ArgumentParser(description=__doc__)
+parser.add_argument("hostname")
+args = parser.parse_args()
 
 # Connect to libvirt
-uri = "esx://%s/?no_verify=1" % hostname
+uri = "esx://%s/?no_verify=1" % args.hostname
 
 # The auth argument is a list that contains 3 items:
 #   - a list of supported credential types
@@ -101,7 +96,7 @@ auth = [[libvirt.VIR_CRED_AUTHNAME, libvirt.VIR_CRED_NOECHOPROMPT],
 try:
     conn = libvirt.openAuth(uri, auth, 0)
 except libvirt.libvirtError:
-    print("Failed to open connection to %s" % hostname)
+    print("Failed to open connection to %s" % args.hostname)
     sys.exit(1)
 
 state_names = { libvirt.VIR_DOMAIN_RUNNING  : "running",
diff --git a/examples/event-test.py b/examples/event-test.py
index eb464d1..18f657a 100755
--- a/examples/event-test.py
+++ b/examples/event-test.py
@@ -7,14 +7,13 @@
 ##############################################################################
 
 import atexit
-import sys
-import getopt
 import os
 import libvirt
 import select
 import errno
 import time
 import threading
+from argparse import ArgumentParser
 from typing import Any, Callable, Dict, List, Optional, TypeVar  # noqa F401
 _T = TypeVar("_T")
 _EventCallback = Callable[[int, int, int, _T], None]
@@ -725,53 +724,29 @@ def myConnectionCloseCallback(conn: libvirt.virConnect, reason: int, opaque: _T)
     run = False
 
 
-def usage() -> None:
-    print("usage: %s [-hdl] [uri]" % (os.path.basename(__file__),))
-    print("   uri will default to qemu:///system")
-    print("   --help, -h   Print this help message")
-    print("   --debug, -d  Print debug output")
-    print("   --loop=TYPE, -l   Choose event-loop-implementation (native, poll, asyncio)")
-    print("   --timeout=SECS  Quit after SECS seconds running")
-
-
 def main() -> None:
-    try:
-        opts, args = getopt.getopt(sys.argv[1:], "hdl:", ["help", "debug", "loop=", "timeout="])
-    except getopt.GetoptError as err:
-        # print help information and exit:
-        print(str(err))  # will print something like "option -a not recognized"
-        usage()
-        sys.exit(2)
-    timeout = None
-    for o, a in opts:
-        if o in ("-h", "--help"):
-            usage()
-            sys.exit()
-        if o in ("-d", "--debug"):
+    parser = ArgumentParser()
+    parser.add_argument("--debug", "-d", action="store_true", help="Print debug output")
+    parser.add_argument("--loop", "-l", choices=("native", "poll", "asyncio"), default=event_impl, help="Choose event-loop-implementation")
+    parser.add_argument("--timeout", type=int, default=None, help="Quit after SECS seconds running")
+    parser.add_argument("uri", nargs="?", default="qemu:///system")
+    args = parser.parse_args()
+
+    if args.debug:
             global do_debug
             do_debug = True
-        if o in ("-l", "--loop"):
-            global event_impl
-            event_impl = a
-        if o in ("--timeout"):
-            timeout = int(a)
-
-    if len(args) >= 1:
-        uri = args[0]
-    else:
-        uri = "qemu:///system"
 
-    print("Using uri '%s' and event loop '%s'" % (uri, event_impl))
+    print("Using uri '%s' and event loop '%s'" % (args.uri, args.loop))
 
     # Run a background thread with the event loop
-    if event_impl == "poll":
+    if args.loop == "poll":
         virEventLoopPollStart()
-    elif event_impl == "asyncio":
+    elif args.loop == "asyncio":
         virEventLoopAIOStart()
     else:
         virEventLoopNativeStart()
 
-    vc = libvirt.openReadOnly(uri)
+    vc = libvirt.openReadOnly(args.uri)
 
     # Close connection on exit (to test cleanup paths)
     def exit() -> None:
@@ -839,7 +814,7 @@ def main() -> None:
     # run the event loop in your main thread if your app is
     # totally event based.
     count = 0
-    while run and (timeout is None or count < timeout):
+    while run and (args.timeout is None or count < args.timeout):
         count = count + 1
         time.sleep(1)
 
diff --git a/examples/guest-vcpus/guest-vcpu-daemon.py b/examples/guest-vcpus/guest-vcpu-daemon.py
index 30fcb9c..b2507fe 100755
--- a/examples/guest-vcpus/guest-vcpu-daemon.py
+++ b/examples/guest-vcpus/guest-vcpu-daemon.py
@@ -1,26 +1,22 @@
 #!/usr/bin/env python3
+"""
+This service waits for the guest agent lifecycle event and reissues
+guest agent calls to modify the cpu count according to the metadata
+set by guest-vcpu.py example
+"""
 
 import libvirt
 import threading
 from xml.dom import minidom
 import time
 import sys
-import getopt
 import os
+from argparse import ArgumentParser
 
 uri = "qemu:///system"
 customXMLuri = "guest-cpu.python.libvirt.org"
 connectRetryTimeout = 5
 
-def usage():
-    print("usage: "+os.path.basename(sys.argv[0])+" [-h] [uri]")
-    print("   uri will default to qemu:///system")
-    print("   --help, -h   Print(this help message")
-    print("")
-    print("This service waits for the guest agent lifecycle event and reissues " +
-           "guest agent calls to modify the cpu count according to the metadata " +
-           "set by guest-vcpu.py example")
-
 class workerData:
     def __init__(self):
         self.doms = list()
@@ -140,21 +136,10 @@ def main():
        time.sleep(1)
 
 if __name__ == "__main__":
-    try:
-        opts, args = getopt.getopt(sys.argv[1:], "h", ["help"])
-    except getopt.GetoptError as err:
-        print(str(err))
-        usage()
-        sys.exit(2)
-    for o, a in opts:
-        if o in ("-h", "--help"):
-            usage()
-            sys.exit()
-
-    if len(args) > 1:
-        usage()
-        sys.exit(1)
-    elif len(args) == 1:
-        uri = args[0]
+    parser = ArgumentParser(description=__doc__)
+    parser.add_argument("uri", nargs="?", default=uri)
+    args = parser.parse_args()
+
+    uri = args.uri
 
     main()
diff --git a/examples/guest-vcpus/guest-vcpu.py b/examples/guest-vcpus/guest-vcpu.py
index 786ef0c..68bb5bf 100755
--- a/examples/guest-vcpus/guest-vcpu.py
+++ b/examples/guest-vcpus/guest-vcpu.py
@@ -1,74 +1,45 @@
 #!/usr/bin/env python3
+"""
+Sets the vCPU count via the guest agent and sets the metadata element
+used by guest-vcpu-daemon.py example
+"""
 
 import libvirt
 import sys
-import getopt
-import os
+from argparse import ArgumentParser
 
 customXMLuri = "guest-cpu.python.libvirt.org"
 
-def usage():
-    print("usage: "+os.path.basename(sys.argv[0])+" [-hcl] domain count [uri]")
-    print("   uri will default to qemu:///system")
-    print("   --help, -h   Print(this help message")
-    print("   --config, -c Modify persistent domain configuration")
-    print("   --live, -l   Modify live domain configuration")
-    print("")
-    print("Sets the vCPU count via the guest agent and sets the metadata element " +
-           "used by guest-vcpu-daemon.py example")
+parser = ArgumentParser(description=__doc__)
+parser.add_argument("--config", "-c", action="store_true", help="Modify persistent domain configuration")
+parser.add_argument("--live", "-l", action="store_true", help="Modify live domain configuration")
+parser.add_argument("domain")
+parser.add_argument("count", type=int)
+parser.add_argument("uri", nargs="?", default="qemu:///system")
+args = parser.parse_args()
 
-uri = "qemu:///system"
-flags = 0
-live = False
-config = False
+flags = (libvirt.VIR_DOMAIN_AFFECT_CONFIG if args.config else 0) | (libvirt.VIR_DOMAIN_AFFECT_LIVE if args.live else 0)
 
-try:
-    opts, args = getopt.getopt(sys.argv[1:], "hcl", ["help", "config", "live"])
-except getopt.GetoptError as err:
-    # print help information and exit:
-    print(str(err)) # will print something like "option -a not recognized"
-    usage()
-    sys.exit(2)
-for o, a in opts:
-    if o in ("-h", "--help"):
-        usage()
-        sys.exit()
-    if o in ("-c", "--config"):
-        config = True
-        flags |= libvirt.VIR_DOMAIN_AFFECT_CONFIG
-    if o in ("-l", "--live"):
-        live = True
-        flags |= libvirt.VIR_DOMAIN_AFFECT_LIVE
+conn = libvirt.open(args.uri)
+dom = conn.lookupByName(args.domain)
 
-if len(args) < 2:
-    usage()
-    sys.exit(1)
-elif len(args) >= 3:
-    uri = args[2]
-
-domain = args[0]
-count = int(args[1])
-
-conn = libvirt.open(uri)
-dom = conn.lookupByName(domain)
-
-if flags == 0 or config:
+if flags == 0 or args.config:
     confvcpus = dom.vcpusFlags(libvirt.VIR_DOMAIN_AFFECT_CONFIG)
 
-    if confvcpus < count:
+    if confvcpus < args.count:
         print("Persistent domain configuration has only " + str(confvcpus) + " vcpus configured")
         sys.exit(1)
 
-if flags == 0 or live:
+if flags == 0 or args.live:
     livevcpus = dom.vcpusFlags(libvirt.VIR_DOMAIN_AFFECT_LIVE)
 
-    if livevcpus < count:
+    if livevcpus < args.count:
         print("Live domain configuration has only " + str(livevcpus) + " vcpus configured")
         sys.exit(1)
 
-if flags == 0 or live:
-    dom.setVcpusFlags(count, libvirt.VIR_DOMAIN_AFFECT_LIVE | libvirt.VIR_DOMAIN_VCPU_GUEST)
+if flags == 0 or args.live:
+    dom.setVcpusFlags(args.count, libvirt.VIR_DOMAIN_AFFECT_LIVE | libvirt.VIR_DOMAIN_VCPU_GUEST)
 
-meta = "<ncpus count='" + str(count) + "'/>"
+meta = "<ncpus count='" + str(args.count) + "'/>"
 
 dom.setMetadata(libvirt.VIR_DOMAIN_METADATA_ELEMENT, meta, "guestvcpudaemon", customXMLuri, flags)
diff --git a/examples/sparsestream.py b/examples/sparsestream.py
index 618c291..80ce0c5 100755
--- a/examples/sparsestream.py
+++ b/examples/sparsestream.py
@@ -1,10 +1,15 @@
 #!/usr/bin/env python3
+"""
+Either uploads local FILE to libvirt VOLUME, or downloads libvirt
+VOLUME into local FILE while preserving FILE/VOLUME sparseness
+"""
 # Example of sparse streams usage
 #
 # Authors:
 #   Michal Privoznik <mprivozn@redhat.com>
 
 import libvirt, sys, os
+from argparse import ArgumentParser
 
 def bytesWriteHandler(stream: libvirt.virStream, buf: bytes, opaque: int) -> int:
     fd = opaque
@@ -94,24 +99,22 @@ def upload(vol: libvirt.virStorageVol, st: libvirt.virStream, filename: str) ->
     os.close(fd)
 
 # main
-if len(sys.argv) != 5:
-    print("Usage: ", sys.argv[0], " URI --upload/--download VOLUME FILE")
-    print("Either uploads local FILE to libvirt VOLUME, or downloads libvirt ")
-    print("VOLUME into local FILE while preserving FILE/VOLUME sparseness")
-    sys.exit(1)
+parser = ArgumentParser(description=__doc__)
+parser.add_argument("uri")
+group = parser.add_mutually_exclusive_group(required=True)
+group.add_argument("--upload", action="store_const", const=upload, dest="operation")
+group.add_argument("--download", action="store_const", const=download, dest="operation")
+parser.add_argument("volume")
+parser.add_argument("file")
+args = parser.parse_args()
 
-conn = libvirt.open(sys.argv[1])
-vol = conn.storageVolLookupByKey(sys.argv[3])
+
+conn = libvirt.open(args.uri)
+vol = conn.storageVolLookupByKey(args.volume)
 
 st = conn.newStream()
 
-if sys.argv[2] == "--download":
-    download(vol, st, sys.argv[4])
-elif sys.argv[2] == "--upload":
-    upload(vol, st, sys.argv[4])
-else:
-    print("Unknown operation: %s " % sys.argv[1])
-    sys.exit(1)
+args.operation(vol, st, args.file)
 
 st.finish()
 conn.close()