updating network emulation

netem

-#! /usr/bin/env python
-
-import json
-import subprocess
-
-def main():
-    module = AnsibleModule(argument_spec=dict(
-        state=dict(required=True),
-        name=dict(required=True,type='str'),
-        device=dict(required=True,type='str'),
-    ))
-
-    j = json.loads(module.params['state'])
-    name = module.params['name']
-    device = module.params['device']
-    changed = False
-    args = ["/sbin/ip",
-            "netns", "exec", name,
-            "tc", "qdisc", "change", "dev", device, "root",
-            "netem"]
-    if 'delay' in j:
-        args.append("delay")
-        args.append(j['delay'])
-        changed = True
-    if 'rate' in j:
-        args.append("rate")
-        args.append(j['rate'])
-        changed = True
-    if 'loss' in j:
-        args.append("loss")
-        args.append(j['loss'])
-        changed = True
-    if changed:
-        cmd = reduce( lambda x,y: "%s %s" % (x,y), args )
-        sargs = map( lambda x: str(x), args )
-        try:
-            subprocess.check_output(sargs,stderr=subprocess.STDOUT)
-        except subprocess.CalledProcessError as e:
-            module.fail_json(msg=e.output)
-    module.exit_json(changed=changed,cmd=cmd)
-
-from ansible.module_utils.basic import *
-main()

netem.py

+#! /usr/bin/env python
+
+import json
+import subprocess
+from argparse import ArgumentParser
+
+parser = ArgumentParser()
+parser.add_argument('-n', '--namespace',
+                    dest='namespace',
+                    help='network namespace for the link to modify'
+                    )
+parser.add_argument('-d', '--device',
+                    dest='device',
+                    help='device to modify'
+                    )
+parser.add_argument('-B, '--bandwidth',
+                    dest='bandwidth',
+                    help='bandwidth to set'
+                    )
+parser.add_argument('-D, '--delay',
+                    dest='delay',
+                    help='link latency'
+                    )
+parser.add_argument('-L, '--loss',
+                    dest='loss',
+                    help='loss rate'
+                    )
+
+args = parser.parse_args()
+
+# Enable network emulation on the device.
+cmd = ["sudo", "/sbin/ip",
+       "netns", "exec", args.namespace,
+       "tc", "qdisc", "change", "dev", args.device, "root",
+       "netem"]
+if args.delay is not None:
+    cmd.append("delay")
+    cmd.append(str(args.delay))
+if args.bandwidth is not None:
+    cmd.append("rate")
+    cmd.append(str(args.bandwidth))
+if args.loss is not None:
+    cmd.append("loss")
+    cmd.append(str(args.loss))
+
+subprocess.check_output(cmd,stderr=subprocess.STDOUT)
+