ValueError exception on tcshow with empty qdisc configuration

[eroullit]

/ # tc qdisc show dev eth0
/ # tcset --device eth0 --delay 100
/ # tcshow --device eth0
{
    "eth0": {
        "outgoing": {
            "network=0.0.0.0/0": {
                "delay": "100.0",
                "rate": "10G"
            }
        },
        "incoming": {}
    }
}
/ # tc qdisc show dev eth0
qdisc htb 1a1a: root refcnt 2 r2q 10 default 1 direct_packets_stat 0 direct_qlen 2
qdisc netem 1a9a: parent 1a1a:2 limit 1000 delay 100.0ms
/ # tcdel --device eth0
[NOTICE] tcconfig: failed to delete qdisc: no qdisc for incomming packets
/ # tc qdisc show dev eth0
/ # tcshow --device eth0
Traceback (most recent call last):
  File "/usr/bin/tcshow", line 11, in <module>
    sys.exit(main())
  File "/usr/lib/python2.7/site-packages/tcconfig/tcshow.py", line 213, in main
    tc_param.update(TcShapingRuleParser(device, logger).get_tc_parameter())
  File "/usr/lib/python2.7/site-packages/tcconfig/tcshow.py", line 74, in get_tc_parameter
    TrafficDirection.OUTGOING: self.__get_shaping_rule(self.device),
  File "/usr/lib/python2.7/site-packages/tcconfig/tcshow.py", line 126, in __get_shaping_rule
    qdisc_param_list = self.__parse_tc_qdisc(device)
  File "/usr/lib/python2.7/site-packages/tcconfig/tcshow.py", line 178, in __parse_tc_qdisc
    run_tc_show(Tc.Subcommand.QDISC, device)))
  File "/usr/lib/python2.7/site-packages/tcconfig/parser.py", line 201, in parse
    raise ValueError("empty text")
ValueError: empty text

It can happen that no qdisc is configured for a specific device and I would have expected that an empty JSON dict to be output.

Regards,

• Emmanuel

[thombashi]

@eroullit
Thank you for your report.

Unfortunately, I could not reproduce the problem in my environment
(Debian 8.6/Fedora 24, tcconfig 0.7.1, python 2.7.12/3.6.0).

# tcdel --device eth0
[NOTICE] tcconfig: failed to delete qdisc: no qdisc for outgoing packets
[NOTICE] tcconfig: failed to delete qdisc: no qdisc for incomming packets
# tcshow --device eth0
{
    "eth0": {
        "outgoing": {},
        "incoming": {}
    }
}

However, it is true that an exception is not properly handled when parsing value is empty.
I've fixed the problem in tcconfig 0.7.2.
Would you upgrade to this version and re-execute the command?

[eroullit]

The published fix works great thanks!

/ # tcshow --debug --device eth0
[DEBUG] subprocrunner: tc class show dev eth0
[DEBUG] tcconfig: tc class parse result: []
[DEBUG] subprocrunner: tc filter show dev eth0
[DEBUG] tcconfig: tc filter parse result: []
[DEBUG] subprocrunner: tc qdisc show dev eth0
[DEBUG] subprocrunner: tc filter show dev eth0 root
{
    "eth0": {
        "outgoing": {},
        "incoming": {}
    }
}
/ # pip freeze | grep tcconfig
tcconfig==0.7.2

[ortaltur]

maybe i'm missing something but the latest version is 0.18.0,
how do i get 0.7.2?

[thombashi]

@ortaltur
You can install tcconfig 0.7.2 with the following command:

pip install tcconfig==0.7.2

However, I would recommend using the latest version (0.18.0).
Is there any problem with the latest version?

[ortaltur]

when i'm executing the tcset and tcdel commands in python script (using subprocess.Popen), i get the following error:
[ERROR] tcconfig: RTNETLINK answers: No such file or directory

[ERROR] tcconfig: Cannot find device "ifb6682"

[WARNING] subprocrunner: command='/sbin/tc filter add dev ifb6682 protocol ip parent 1a1a: prio 2 u32 match ip dst 0.0.0.0/0 match ip src 0.0.0.0/0 match ip dport 30302 0xffff flowid 1a1a:1', returncode=1, stderr=Cannot find device "ifb6682"

p.s:
in 0.7.2 the tcdel command doesn't accept --all

[thombashi]

@ortaltur
Could you try the following troubleshooting procedure:
http:https://tcconfig.readthedocs.io/en/latest/pages/troubleshooting.html#rtnetlink-answers-no-such-file-or-directory

And, please use the latest version of tcconfig.
Looks like there is no need to use the old version.