parsing text from "ethtool" command

[Jean-Michel Pichavant]

extraspecialbitter wrote:
> I'm still trying to write that seemingly simple Python script to print
> out network interfaces (as found in the "ifconfig -a" command) and
> their speed ("ethtool <interface>").  The idea is to loop for each
> interface and
> print out its speed.  I'm looping correctly, but have some issues
> parsing the output for all interfaces except for the "pan0"
> interface.  I'm running on eth1, and the "ifconfig -a" command also
> shows an eth0, and of course lo.  My script is trying to match on the
> string "Speed", but I never seem to successfully enter the "if"
> clause.
>
> First, here is the output of "ethtool eth1":
>
> =================
>
> Settings for eth1:
> 	Supported ports: [ TP ]
> 	Supported link modes:   10baseT/Half 10baseT/Full
> 	                        100baseT/Half 100baseT/Full
> 	Supports auto-negotiation: Yes
> 	Advertised link modes:  10baseT/Half 10baseT/Full
> 	                        100baseT/Half 100baseT/Full
> 	Advertised pause frame use: No
> 	Advertised auto-negotiation: Yes
> 	Speed: 100Mb/s
> 	Duplex: Full
> 	Port: Twisted Pair
> 	PHYAD: 1
> 	Transceiver: internal
> 	Auto-negotiation: on
> 	MDI-X: off
> 	Supports Wake-on: pumbag
> 	Wake-on: g
> 	Current message level: 0x00000001 (1)
> 	Link detected: yes
>
> =================
>
> The script *should* match on the string "Speed" and then assign "100Mb/
> s" to a variable, but is never getting past the second if statement
> below:
>
> =================
>
> #!/usr/bin/python
>
> # Quick and dirty script to print out available interfaces and their
> speed
>
> # Initializations
>
> output = " Interface: %s Speed: %s"
> noinfo = "(Speed Unknown)"
> speed  = noinfo
>
> import os, socket, types, subprocess
>
> fp = os.popen("ifconfig -a")
> dat=fp.read()
> dat=dat.split('\n')
> for line in dat:
>     if line[10:20] == "Link encap":
>        interface=line[:9]
>        cmd = "ethtool " + interface
>        gp = os.popen(cmd)
>        fat=gp.read()
>        fat=fat.split('\n')
>        for line in fat:
>            if line[0:6] == "Speed":
>                try:
>                    speed=line[8:]
>                except:
>                    speed=noinfo
> print output % (interface, speed)
>
> =================
>
> Again, I appreciate everyone's patience, as I'm obviously I'm a python
> newbie.  Thanks in advance!
>   
Hi, without starting a flamewar about regular expression, they sometimes 
can become usefull and really simplify code:

s1 = """eth0      Link encap:Ethernet  HWaddr 00:1d:09:2b:d2:be
          inet addr:192.168.200.176  Bcast:192.168.200.255  
Mask:255.255.255.0
          inet6 addr: fe80::21d:9ff:fe2b:d2be/64 Scope:Link
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
          RX packets:297475688 errors:0 dropped:7 overruns:0 frame:2
          TX packets:248662722 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000
          RX bytes:2795194692 (2.6 GiB)  TX bytes:2702265420 (2.5 GiB)
          Interrupt:17

lo        Link encap:Local Loopback
          inet addr:127.0.0.1  Mask:255.0.0.0
          inet6 addr: ::1/128 Scope:Host
          UP LOOPBACK RUNNING  MTU:16436  Metric:1
          RX packets:5595504 errors:0 dropped:0 overruns:0 frame:0
          TX packets:5595504 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:0
          RX bytes:1601266268 (1.4 GiB)  TX bytes:1601266268 (1.4 GiB)

"""

import re

itfs = [section for section in s1.split('\n\n') if section and section 
!= '\n'] # list of interfaces sections, filter the empty sections

for itf in itfs:
    match = re.search('^(\w+)', itf) # search the word at the begining 
of the section
    interface = match and match.group(1)
    match = re.search('MTU:(\d+)', itf) # search for the field MTU: and 
capture its digital value
    mtu = (match and match.group(1)) or 'MTU not found'
    print interface, mtu


 >>> eth0 1500
 >>> lo 16436

If you're not familiar with python regexp, I would advise to use 
kodos.py (google it), it really does help.
The strong point about the code above, is that it removes all the 
tedious if then else logic and the arbitrary slice indexes.

JM

PS : I cannot test the 'Speed' because it's absent from my ifconfig 
display, but you should be able to figure it out :o)