[Tutor] Code critique

[Peter Otten]

Bo Morris wrote:

> Thank you all for the helpful criticism. I wish I was able to catch on to
> what you are suggesting more quickly.
> 
> Based on your recommendations, I have come up with the following so far,
> however I just dont see it as easily as I did while using the if/elif
> statements.
> 
> This is what I have so far. I can not figure out how to iterate through
> the dictionary inserting each value where "png_file" should be and execute
> the code for each ip address in the list. I was able to do it using the
> if/elif statements, but I am afraid I am lost trying to do it another way.
> 
> ipList = ['ip-1', 'ip-2', 'ip-3', 'ip-4', 'ip-5', 'ip-6', 'ip-7', 'ip-8',
> 'ip-9']
> 
> host = {'3102EHD-01108':'3102EHD-01108.png',
> '3102EHD-01109':'3102DHD-01109.png',
> '3102EHD-MUTV-1082':'3102EHD-01082.png',
> '3102DHD-01033':'3102DHD-MUTV-1033.png',
> 'Encoder':'3102EHD-01302.png',
> '3102DHD-01149':'3102DHD-01149.png',
> '3102EHD-01125':'3102EHD-01125.png',
> '3102DHD-01144':'3102DHD-01144.png',
> '3102EHD-01105':'3102EHD-01105.png'}
> 
> # iterate through the dictionary inserting the png file
> def get_png_file(?):
>     process = get_png_file.get(hostname, png_file)
>     s.exec_command('export DISPLAY=:0.0; /Downloads/Hourly/win.sh')
>     sftp = s.open_sftp()
>     sftp.get('/Downloads/Hourly/'png_file,'/Downloads/Hourly/'png_file)
>     sftp.close()
>     print 'file recieved'
> 
> user = 'user'
> passwd = 'password'
> s = paramiko.SSHClient()
> s.set_missing_host_key_policy(paramiko.AutoAddPolicy())
> 
> # iterate through the list and do the below for each
> for ip in ipList:
>     s.connect(ip,22,user,passwd,timeout=4)
> ####since I have all the hostnames in the dic, and I am removing
> ####the if/elif statments, do I need the below command 'echo $HOSTNAME'?
>     stdin, stdout, stderr = s.exec_command('echo $HOSTNAME')
>     out = stdout.read()
>     get_png_file(?)
> 

As hinted in my previous post I don't think you need a dict here. Once you 
have the hostname you can build the filename from it with hostname + ".png".

Here's what I had in mind, unfortunately totally untested:

#!/usr/bin/python
import os
import paramiko

ip_list = [
    'ip-1', 'ip-2', 'ip-3', 'ip-4', 'ip-5',
    'ip-6', 'ip-7', 'ip-8', 'ip-9']

def connect(ip):
    user = 'user'
    passwd = 'password'

    s = paramiko.SSHClient()
    s.set_missing_host_key_policy(paramiko.AutoAddPolicy())
    s.connect(ip, 22, user, passwd, timeout=4)
    stdin, stdout, stderr = s.exec_command('echo $HOSTNAME')
    hostname = stdout.read().strip()

    filename = hostname + ".png"
    png_source = os.path.join("/Downloads/Hourly", filename)
    png_dest = os.path.join("/Downloads/Hourly", hostname, filename)

    s.exec_command('export DISPLAY=:0.0; /Downloads/Hourly/win.sh')

    sftp = s.open_sftp()
    sftp.get(png_dest, png_source)
    sftp.close()

    print "file", png_dest, "received"

for ip in ip_list:
    connect(ip)