[dpdk-dev] [PATCH v2 1/6] dpdk-devbind: use argparse instead of getopt

[Stephen Hemminger <stephen@networkplumber.org>]

Using the python standard argument parser instead of C library
style getopt gives a number of advantages such as checking
for conflicting arguments, restricting choices, and automatically
generating help messages.

The result is similar to the original the only visible change
is that some of the help messages are now less wordy.

Signed-off-by: Stephen Hemminger <stephen@networkplumber.org>
---
 usertools/dpdk-devbind.py | 203 ++++++++++++++++----------------------
 1 file changed, 86 insertions(+), 117 deletions(-)

diff --git a/usertools/dpdk-devbind.py b/usertools/dpdk-devbind.py
index 99112b7ab794..e0b74c5a3e41 100755
--- a/usertools/dpdk-devbind.py
+++ b/usertools/dpdk-devbind.py
@@ -5,8 +5,9 @@
 
 import sys
 import os
-import getopt
 import subprocess
+import argparse
+
 from glob import glob
 from os.path import exists, abspath, dirname, basename
 from os.path import join as path_join
@@ -82,82 +83,6 @@
 force_flag = False
 args = []
 
-
-def usage():
-    '''Print usage information for the program'''
-    argv0 = basename(sys.argv[0])
-    print("""
-Usage:
-------
-
-     %(argv0)s [options] DEVICE1 DEVICE2 ....
-
-where DEVICE1, DEVICE2 etc, are specified via PCI "domain:bus:slot.func" syntax
-or "bus:slot.func" syntax. For devices bound to Linux kernel drivers, they may
-also be referred to by Linux interface name e.g. eth0, eth1, em0, em1, etc.
-If devices are specified using PCI <domain:>bus:device:func format, then
-shell wildcards and ranges may be used, e.g. 80:04.*, 80:04.[0-3]
-
-Options:
-    --help, --usage:
-        Display usage information and quit
-
-    -s, --status:
-        Print the current status of all known network, crypto, event
-        and mempool devices.
-        For each device, it displays the PCI domain, bus, slot and function,
-        along with a text description of the device. Depending upon whether the
-        device is being used by a kernel driver, the igb_uio driver, or no
-        driver, other relevant information will be displayed:
-        * the Linux interface name e.g. if=eth0
-        * the driver being used e.g. drv=igb_uio
-        * any suitable drivers not currently using that device
-            e.g. unused=igb_uio
-        NOTE: if this flag is passed along with a bind/unbind option, the
-        status display will always occur after the other operations have taken
-        place.
-
-    --status-dev:
-        Print the status of given device group. Supported device groups are:
-        "net", "baseband", "crypto", "event", "mempool" and "compress"
-
-    -b driver, --bind=driver:
-        Select the driver to use or \"none\" to unbind the device
-
-    -u, --unbind:
-        Unbind a device (Equivalent to \"-b none\")
-
-    --force:
-        By default, network devices which are used by Linux - as indicated by
-        having routes in the routing table - cannot be modified. Using the
-        --force flag overrides this behavior, allowing active links to be
-        forcibly unbound.
-        WARNING: This can lead to loss of network connection and should be used
-        with caution.
-
-Examples:
----------
-
-To display current device status:
-        %(argv0)s --status
-
-To display current network device status:
-        %(argv0)s --status-dev net
-
-To bind eth1 from the current driver and move to use igb_uio
-        %(argv0)s --bind=igb_uio eth1
-
-To unbind 0000:01:00.0 from using any driver
-        %(argv0)s -u 0000:01:00.0
-
-To bind 0000:02:00.0 and 0000:02:00.1 to the ixgbe kernel driver
-        %(argv0)s -b ixgbe 02:00.0 02:00.1
-
-To bind all functions on device 0000:02:00 to ixgbe kernel driver
-        %(argv0)s -b ixgbe 02:00.*
-
-    """ % locals())  # replace items from local variables
-
 # check if a specific kernel module is loaded
 def module_is_loaded(module):
     global loaded_modules
@@ -677,38 +602,93 @@ def parse_args():
     global status_dev
     global force_flag
     global args
-    if len(sys.argv) <= 1:
-        usage()
-        sys.exit(0)
 
-    try:
-        opts, args = getopt.getopt(sys.argv[1:], "b:us",
-                                   ["help", "usage", "status", "status-dev=",
-                                    "force", "bind=", "unbind", ])
-    except getopt.GetoptError as error:
-        print(str(error))
-        print("Run '%s --usage' for further information" % sys.argv[0])
+    parser = argparse.ArgumentParser(
+        description='Utility to bind and unbind devices from Linux kernel',
+        formatter_class=argparse.RawDescriptionHelpFormatter,
+        epilog="""
+Examples:
+---------
+
+To display current device status:
+        %(prog)s --status
+
+To display current network device status:
+        %(prog)s --status-dev net
+
+To bind eth1 from the current driver and move to use vfio-pci
+        %(prog)s --bind=vfio-pci eth1
+
+To unbind 0000:01:00.0 from using any driver
+        %(prog)s -u 0000:01:00.0
+
+To bind 0000:02:00.0 and 0000:02:00.1 to the ixgbe kernel driver
+        %(prog)s -b ixgbe 02:00.0 02:00.1
+""")
+
+    parser.add_argument(
+        '-s',
+        '--status',
+        action='store_true',
+        help="Print the current status of all known devices.")
+    parser.add_argument(
+        '--status-dev',
+        help="Print the status of given device group.",
+        choices=['net', 'baseband', 'crypto', 'event', 'mempool', 'compress'])
+    bind_group = parser.add_mutually_exclusive_group()
+    bind_group.add_argument(
+        '-b',
+        '--bind',
+        metavar='DRIVER',
+        help="Select the driver to use or \"none\" to unbind the device")
+    bind_group.add_argument(
+        '-u',
+        '--unbind',
+        action='store_true',
+        help="Unbind a device (equivalent to \"-b none\")")
+    parser.add_argument(
+        '--force',
+        action='store_true',
+        help="""
+Override restriction on binding devices in use by Linux"
+WARNING: This can lead to loss of network connection and should be used with caution.
+""")
+    parser.add_argument(
+        'devices',
+        metavar='DEVICE',
+        nargs='*',
+        help="""
+Device specified as PCI "domain:bus:slot.func" syntax or "bus:slot.func" syntax.
+For devices bound to Linux kernel drivers, they may be referred to by interface name.
+""")
+
+    opt = parser.parse_args()
+
+    if opt.status_dev:
+        status_flag = True
+        status_dev = opt.status_dev
+    if opt.status:
+        status_flag = True
+        status_dev = "all"
+    if opt.force:
+        force_flag = True
+    if opt.bind:
+        b_flag = opt.bind
+    elif opt.unbind:
+        b_flag = "none"
+    args = opt.devices
+
+    if not b_flag and not status_flag:
+        print("Error: No action specified for devices. "
+              "Please give a --bind, --ubind or --status option",
+              file=sys.stderr)
+        parser.print_usage()
         sys.exit(1)
 
-    for opt, arg in opts:
-        if opt == "--help" or opt == "--usage":
-            usage()
-            sys.exit(0)
-        if opt == "--status-dev":
-            status_flag = True
-            status_dev = arg
-        if opt == "--status" or opt == "-s":
-            status_flag = True
-            status_dev = "all"
-        if opt == "--force":
-            force_flag = True
-        if opt == "-b" or opt == "-u" or opt == "--bind" or opt == "--unbind":
-            if b_flag is not None:
-                sys.exit("Error: binding and unbinding are mutually exclusive")
-            if opt == "-u" or opt == "--unbind":
-                b_flag = "none"
-            else:
-                b_flag = arg
+    if b_flag and not args:
+        print("Error: No devices specified.", file=sys.stderr)
+        parser.print_usage()
+        sys.exit(1)
 
     # resolve any PCI globs in the args
     new_args = []
@@ -723,17 +703,6 @@ def do_arg_actions():
     global force_flag
     global args
 
-    if b_flag is None and not status_flag:
-        print("Error: No action specified for devices. "
-              "Please give a -b or -u option", file=sys.stderr)
-        usage()
-        sys.exit(1)
-
-    if b_flag is not None and len(args) == 0:
-        print("Error: No devices specified.", file=sys.stderr)
-        usage()
-        sys.exit(1)
-
     if b_flag == "none" or b_flag == "None":
         unbind_all(args, force_flag)
     elif b_flag is not None:
-- 
2.27.0