Python Scripting

Python Try and Except Error Handling

March 4, 2023 by atish88076

In this script, we will see how we can implement error handling in python scripting. We will use the try and except method. Sometimes if there is an error in the script or in the remote device where you are trying to connect then the script will break and stop working.

Error handling using the try-and-except method deals with these kinds of situations. If you are using any particular python library, then check the documentation to see available exception errors.

Python Try and Except Error Handling

Below is the script which we have used for error handling. Check out the link for email sending script in python. Full tutorial for python scripting for videos for storage admin.

import paramiko
p = paramiko.SSHClient()
cred = open("cred.csv","r")
for i in cred.readlines():
    try:
        line=i.strip()
        ls =line.split(",")
        p.set_missing_host_key_policy(paramiko.AutoAddPolicy())
        p.connect("%s"%ls[0],port =22, username = "%s"%ls[1], password="%s"%ls[2])
        stdin, stdout, stderr = p.exec_command("uname -a")
        opt = stdout.readlines()
        opt ="".join(opt)
        temp=open("%s.txt"%ls[0],"w")
        temp.write(opt)
        temp.close()
    except Exception as error:
        print(error)
cred.close()

Watch the video for a full explanation and subscribe to the channel for more such videos.

Conclusion

The given example is simple, you can use this method in various scenarios to catch errors and save them into a log file for further checks. While using this method, the script will continue to run, even if the errors are critical.

Python Convert All Elements Of List To String

June 5, 2021 by Manoj Patel

If you use list frequently in your python code, then you may have come across a situation, where you need to convert all elements of List to string. In this post, we will see two approaches to do that. First, we will convert the entire list to a string so that it will become a line. Second, we will convert all elements to strings keeping the list as it is.

Automate Boring Stuff With Python

#Scenario 1


Input: list1=["I","am","a","list"]

Output: I am a list

#Scenario 2


Input: list2=["I","am","a","list2",1,2,3]

Output: ["I","am","a","list2","1","2","3"]

Convert Entire List To A Line In Python

We can convert an entire list to a line or string by using the Join operator. The join operator is an inbuilt python function, which joins a list with a separator. A separator can be anything, but the most common are space, comma, colon, and even a special character. We are going to use a space separator to convert the list into a single string or line.

#Create a List
list1=["I","am","a","list1"]
#Convert list using join operator
line=" ".join(list1)
#Print The output
print(line)
#Output
"I am a list1"

Python Convert All Elements Of List To String

Now you may notice that the second list contains strings and integers. Hence, and it is a list with mixed data types, and if use joins operator directly it will give a TypeError as below.

TypeError: sequence item 4: expected str instance, int found

In order to resolve this first, you need to convert all elements to string keeping the list as it is and then use the join operator. We will use the map function and the join operator to solve it.

>>> list2=["I","am","a","list2",1,2,3]
>>> newlist=list(map(str,list2))
>>> print(newlist)
['I', 'am', 'a', 'list2', '1', '2', '3']
>>> opt=" ".join(newlist)
>>> print(opt)
I am a list2 1 2 3
>>>

Conclusion

You can the same code to convert all elements of the list to int or float. However, you must check if the list’s elements are of correct data types to avoid any TypeError.

As a part of storage automation, I have written many python scripts and the list is my favorite. A python list can be useful in storing multiple variables which can be processed in many ways. I strongly suggest playing around with the python list, especially using it with for loop.

I hope, this post was helpful, Check out our YouTube channel for a basic tutorial on python and storage admin videos.

How To Send Email In Python Using SMTPLIB

January 15, 2021 by Atish patel

In this script, we will see how to send emails in Python using the SMTPLIB library. SMTPLIB is a popular python library that is useful to send email via script.

You do not have to install it, because the library comes by default. In the below python script we use Gmail for the demo, but in your case, you have to use your email server.

Before you understand the script, let’s see what are the details you need to send an email in python. Check out the python series for storage admin.

Pre-Requisites To Send Email In Python

In order for the script to work, you need to import the library. As the SMTPLIB library comes by default with python, hence, you do not need to install it.

You also need a SMTP server and ports. You can get them for your team who are responsible for managing the exchange servers.

Once you get the SMTP server and port, make sure that the server where your script will run is allowed to send an email. Usually, a server is allowed to send an email if it is added to the SMTP relay.

Python Scripts to Send Email

Below is the entire script which sends email in python. You just have to modify the SMTP server and port. Notice that the username and password for the Gmail account are saved in the text file. If you are using the script in your company, then you can remove those lines.

import smtplib
from email.mime.multipart import MIMEMultipart
from email.mime.text import MIMEText
msg= MIMEMultipart('alternative')
msg['Subject'] = 'Test Mail'
From = "fromemailaddress@gmail.com"
To = "toemailaddress@yahoo.co.in"
Cc = "ccemailaddress@yahoo.co.in"
text = "Info Collector"
data = "Body content of the mail"
part1 = MIMEText(text, 'plain')
part2 = MIMEText(data, 'plain')
msg.attach(part1)
msg.attach(part2)
s=smtplib.SMTP('smtp.gmail.com', 587)
s.ehlo()
s.starttls()
gmail_cred = open("gmail_cred.txt","r").read().split(",")
s.login(gmail_cred[0],gmail_cred[1])
s.sendmail(From, To ,msg.as_string())
s.quit()

If you need more details on the script, then watch the below YouTube video. This video is part of series which explains python scripting for Storage Admin.

Python Script For Login Multiple Server

August 29, 2020 by Atish patel

This post will see how to write a python script for login multiple Unix servers and execute a command. Additionally, the python script is going to save the output of that command in a text file.

Login To Multiple Server And Run Unix Command Python Script

Automate Boring Stuff With Python

Overview of Python Script For Login Multiple Unix Server

Before writing any scripts, it necessary to prepare the steps. It would be best if you considered every action that you do manually.

Below are the overall steps of Python Script For Login Multiple Unix Server

Install the Paramiko module.
Read the credential from a CSV file.
Log in to multiple Unix servers one by one.
Execute a command.
Save the output in a text file.

You can check out the below YouTube video for a live demo of the script.

Prerequisite For Python Script Login Multiple Server

Before we start writing the script, let us discuss the prerequisite to writing the script.

To write a Python Script For Login multiple servers, you need a paramiko library. Hence, first, install the python library.

Paramiko library is useful to connect any device which supports SSH connectivity.

Go to command prompt and execute the below command to install the paramiko module.

pip install paramiko

Once you install the library, create a CSV file in the below format and name it, “cred.csv.”

Read python file handling post.

server1,username,password
server2,username,password

Keep the cred.csv file and the script in the same location.

Complete Python Script For Login Multiple Unix Server

Below is the complete python which can login to the multiple server and execute command.

import paramiko
p = paramiko.SSHClient()
cred = open("cred.csv","r")
for i in cred.readlines():
    line=i.strip()
    ls =line.split(",")
    p.set_missing_host_key_policy(paramiko.AutoAddPolicy())
    p.connect("%s"%ls[0],port =22, username = "%s"%ls[1], password="%s"%ls[2])
    stdin, stdout, stderr = p.exec_command("uname -a")
    opt = stdout.readlines()
    opt ="".join(opt)
    print(opt)
    temp=open("%s.txt"%ls[0],"w")
    temp.write(opt)
    temp.close()
cred.close()

Explanation

The script’s first line imports a library, and the second line creates an object “p.”

The third line opens the cred.csv file and stores the content in the variable cred.

Then a for loop starts and reads all the lines of the credential file. Each line is converted into a python list with split function.

From the python list, the script fetches the server name and its user name and password. After that, using those credentials, the script connects to the device and executes the command.

The variable “opt” stores the output of the command. Finally, the script creates a file with the server name and stores the content in it.

Conclusion For Storage Admin

The script is capable of connecting to any device that supports SSH. Hence, a storage admin can use this python script to collect logs from Cisco, Brocade switch, Isilon, and NetApp.

You have to modify the “cred.csv” file and mention the correct command.

Checkout out the post for sending mail in python.

How to Convert Python Scripts To Binary Files (.exe)

July 7, 2020 by Atish patel

In this post, we will see how we can convert python scripts to binary files. In a more pythonic way how to convert .py file to .exe file.

But first, lets understand why there is a need of binary files.

Automate Boring Stuff With Python

How To Convert Python Files To Binary Files

Merits of Binary Files

The binary file can be executed in any system without installing the actual scripting language or any module. A developer can convert scripts to binary files and give it to the client. A client can use the binary file to run the script.

One thing to note that you have to run the binary file in 64 bit operating system only if you have used a 64 bit operating system to convert .py file to .exe file.

Check out our entire posts on python scripting for storage admins.

Convert a Python Scripts To Binary Files

We will use a python module called pyinstaller to convert a .py file to .exe file. Py

Step 1. Open Command Prompt

Step 2. Install pyinstaller module by executing below command

pip install pyinstaller

Step 2. Traverse to the directory where the python file is located.

Step 3. Convert Python Files to Binary Files

pyinstaller info_collector.py –onefile

The above command will bundle all dependencies and convert python scripts to binary files. The location of the .exe file will be displayed at the bottom.

Just copy that .exe file and run it.

If you still need more information, then check out the below YouTube video. It explains a step by step guide to convert a .py file to .exe file.

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