Forem: Ramu Ummadishetty

Token vs Session Based Authentication

Ramu Ummadishetty — Tue, 25 Oct 2022 09:11:41 +0000

Session based authentication

In session based authentication server stores the user information and each users has a corresponding session ID to validate them.
Session based or token based authentication is a process that allows the server to handle multiple requests from the same user without asking the user to login again
When user log out server ends the session or invalidate the token and revokes the authentication

Most of the time this session ID and Token is shared to browser in form of HTTP cookie. For each request this cookie is included for validating the user

Token based Authentication

Token-based authentication system stores this info directly in some sort of token.
Using token server decodes it for user identity and it reduces the process of storing the session ID's

Token auth flow

Users login with their credentials.
Those credentials are provided to server for validation and if those are valid a signed token will be given to user
For each request and response this signed token is included for user identity
This token can be included in headers or cookies
Every time server upon validating the token shares the resources for user

Token security

Integrity of token is protected by signing the token and verifying its signature each time when it arrives at server
Server uses secret key to generate the special string for signing the token. If any user or third party tampers the token signature will be not valid

Check for JSON Web Tokens here

JSON Web Tokens

Ramu Ummadishetty — Tue, 25 Oct 2022 09:11:18 +0000

JSON web token is one of the most commonly used type of authentication tokens.

It consists of three components

Header, Payload, signature

All this 3 are separated by '.'

Header.payload.signature

eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJzdWIiOiIxMjM0NTY3ODkwIiwibmFtZSI6IkpvaG4gRG9lIiwiaWF0IjoxNTE2MjM5MDIyfQ.SflKxwRJSMeKKF2QT4fwpMeJf36POk6yJV_adQssw5c

This is base64url-encoded string

Header

eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9 - is a header consists of algorithm used to generate the signature.

{ "alg": "HS256", "typ": "JWT" }

Payload

eyJzdWIiOiIxMjM0NTY3ODkwIiwibmFtZSI6IkpvaG4gRG9lIiwiaWF0IjoxNTE2MjM5MDIyfQ - This contains the user meta data

{
  "sub": "1234567890",
  "name": "John Doe",
  "iat": 1516239022
}

Signature

SflKxwRJSMeKKF2QT4fwpMeJf36POk6yJV_adQssw5c - It helps to validate the token that no one is tampered with it

Token's signatures need to be verified at server end compulsory.

Token need to restricted with 'alg' field in backend with some algorithm it should not left to 'none'

HMAC and RSA

HMAC requires the token to be signed with a key and then later verified with the same key(secret key)
RSA token first creates with private key and it is verified with public key later

Thanks for reading

Read my article about token based authentication

NGINX

Ramu Ummadishetty — Mon, 24 Oct 2022 14:53:51 +0000

Installing in Debian/Ubuntu Machine

Installing from Ubuntu repository

$ sudo apt-get update

$ sudo apt-get install nginx

To verify the nginx installation

$ sudo systemctl status nginx

Uninstalling Nginx

$ sudo apt-get purge nginx nginx-common

from Ubuntu repo we get outdated nginx version so for latest we can install from nginx repo

Installing from Official Nginx repository

$ sudo wget https://nginx.org/keys/nginx_signing.key
$ sudo apt-key add nginx_signing.key

$ sudo vi /etc/apt/sources.list

*Here i am using vi editor to save the changes use Esc :wq
*Add the below two lines into this sources.list
deb https://nginx.org/packages/mainline/debian/ <CODENAME> nginx deb-src https://nginx.org/packages/mainline/debian/ <CODENAME> nginx
Here replace CODENAME with your OS CODENAME
to know CODENAME use this cmd

$ sudo cat /etc/lsb-release

 $ sudo apt-get update

$ sudo apt-get install nginx

To know nginx status

$ sudo systemctl status nginx

using PS we can get the nginx status

$ ps -ef | grep nginx

You will find master and worker process then its working fine

http://localhost/

Nginx by default runs on port 80, HTTP server

Start nginx

$ sudo systemctl start nginx

Key nginx folders,files,cmds

/etc/nginx/ - default nginx configuration files located here

/etc/nginx/nginx.conf - default nginx configuration entry point used by nginx service.Contain the global settings like logs location,workers, files locations etc

/etc/nginx/conf.d - default http server configuration file,which is added in http directive of nginx.conf referred using inculde(include /etc/nginx/conf.d/*.conf;)

/var/log/nginx - store the access and error log of nginx server.
access.log - logs each request
error.log - logs error events and for debugging

$ nginx -v
$ nginx -V
$ nginx -t
$ nginx -v
$ nginx -h

Thanks for reading

Python UNIT Testing

Ramu Ummadishetty — Tue, 13 Jul 2021 12:53:56 +0000

UNIT Testing

It is the processing of testing whether a particular unit is working properly or not is called unit testing

Test Scenario vs Test Case vs Test Suite

Test Scenario consists of multiple test case for single scenario
So there will be different scenarios consists of test cases for a given application example of one scenario is testing login functionality.
Test Suite is something like grouping of test cases and executing them at a time

Implementing Python Unit testing

We will use Python in-built module unittest
We will use TestCase class to implement
We also use 3 instance methods setUp(), test(), tearDown()
Here is the simple test class
Output of above code is
Here we need to be careful that setUp and tearDown method names are fixed but we can change the test method name as we like bit it need to be prefix with "test" example test_sample(), test1().
We can include as many test methods we want into the class

Note
For every test method setUp(),tearDown() methods will be executed.
To avoid this repeated call of setUp and tearDown methods we can use setUpClass(), tearDownClass() methods, now only one time setup and teardown methods are called regardless of how many number of testcases.

O/P

You can also use assert functions in test method

Hope you learned something!!!
Happy coding!!!

AMI=Amazon Machine Image,Custom AMI

Ramu Ummadishetty — Sat, 03 Jul 2021 15:40:33 +0000

AMI is something like preconfigured template with required server configuration.
By using this AMI we can quickly create as many instance we want Creating your own custom AMI For creating custom AMI you need to have your own instance running. If you don't know how to create a instance please check this article below

AWS Creating an EC2 Instance

Ramu Ummadishetty ・ Jun 23 ・ 2 min read

#aws #devops #cloud #tutorial

After you have instance go to instances select your instance click on Actions and click on Image and Templates and select Create Image and enter create image

Enter your image name
Go to AMI section which is present in the side nav bar
Here you can find your AMIs
Once the AMI is available go to instances click on launch instance

Now here in choose AMI section select My AMIs

You can see your own custom created AMI here

Select it and follow the same instructions that we use for creating instance.

That's it, hope you enjoyed it!

EBS-Elastic Block Store, Creating Additional Volume,Snapshots

Ramu Ummadishetty — Mon, 28 Jun 2021 14:54:28 +0000

EBS is a storage volume for an EC2 instance.

By default while creating EC2 instance root volume is used
EBS is something like hard disk

Root volumes are set to deleted when instance is terminated.
In this case we can use additional volumes which can be attached and detached at any time from the instance and it is not deleted by default when instance is deleted
Additional volumes can be attached to running instance in same availability zone
Table Of Contents

Creating Additional Volume for instance
Disk Read/Write operations
Unmount Additional Volume
Snapshot of EBS Volume

Creating additional volume

Step1
First you need to have running instance to attach a volume to it
If you don't have running instance please check this

AWS Creating an EC2 Instance

Ramu Ummadishetty ・ Jun 23 '21

#aws #devops #cloud #tutorial

to create EC2 instance

Click on Volumes in Elastic Block store which is present in left sidebar

After getting into volumes Click on Create Volume

Make sure you select the current available zone of which your instance is running.Select the additional volume size
Add tag nothing but your additional volume name and then click on create volume

Successfully volume created now it is available to attach to any instance

Now select additional volume and click on attach then select Attach Volume

Select the instance that you want to attach and click on attach

Now volume status will be in-use

Making disk usable

Now connect to your instance using ssh and execute following cmd

# sudo fdisk -l

you can see
Disk /dev/xvda - root volume
Disk /dev/xvdf - additional volume

Its not enough that attaching a volume doesn't make that additional volume usable.
It just like new pen drive we need to format and mount it

# sudo mkfs.ext4 /dev/xvdf

# mkdir myfolder
# sudo mount /dev/xvdf myfolder/

Now it is successfully attached and we can use it for read and write operations

Unmount additional volume

# umount myfolder/

Don't detach additional volume directly from EBS please unmount it in specific instance

you can cross-check again

Now go to the EBS volumes tab and select additional volume and detach it

Now the detached volume will be available for use and data created in it will be also persisted and we can also attach it to another running instance

Note: Please don't use this below cmd if you want data to be persisted while attaching the volume to another instance

sudo mkfs.ext4 /dev/xvdf

If you use the above cmd again means data will be erased
use the above cmd only when it is new volume

just use below cmds and mount the additional volume in any instance

# mkdir myfolder
# sudo mount /dev/xvdf myfolder/

Snapshot of EBS volume

Note: Your created additional volume can be used only for one instance at a time and can not be used for multiple instances parallel

When you want to share one volume data to multiple instance then create a snapshot of that volume and create another new volume using that snapshot as template

Here snapshot is nothing but "image" of am EBS volume, which can be used as backup of volume or used to create a duplicate.
You need to be clear that snapshot can not be attached and detached to an EC2 instance it is not an active EBS volume
But, one can create EBS volume using this snapshot

Creating snapshot

Click on Volumes and select a volume that you want to create a snapshot, go to actions and click on create snapshot

Enter Description and click on Create snapshot

Now go to snapshot section and you can see the list of snapshots

Select the snapshot click on actions and select create volume

Note: here size need to be >= volume size not less than volume
Select availability zone and click on create volume

Go to Volumes you find new volume created you use add tag for specifying names to volumes while creating it or else you can also edit directly on double click on Name of volume

As it is not new volumes you can directly mount it to any instance with out formatting it

AWS Creating an EC2 Instance

Ramu Ummadishetty — Wed, 23 Jun 2021 15:20:30 +0000

EC2 stands for Amazon Elastic Compute cloud.Simple way you will get a VM in the cloud just like your PC.
Advantage of this EC2 is scalable computing capacity, can launch as many as virtual servers as you required.

Now will see how to configure EC2 in AWS
Before configuration make sure that you have sign up in AWS

Step1
click on services on top left and click on EC2 under compute section

step2
click on launch instance

setp3
Here in the search box please search and select for your required operating system that needed to be present in the instance

step4
Choose instance type based on your requirement
and click on next: configure instance details present below

step5
select your required region and number of instance and click on add storage

step6
select the storage and click on add tag

step7
click on add new tag name

step8
Here configure your security group like click on add rule and add what ever the protocols you needed

step9
click on review and launch instance
create new .pem file like it creates public key and private key
where you download private key which is used for connecting to instance from your machine

make sure that you .pem file only works for the selected region instance only
click on launch instance

Again click on service , EC2 and click on running instances

select and click on connect on top

You will find ssh client and ssh cmd

use that in your git bash or terminal to connect to server
Make sure you use 'sudo' if you get permission denied error

Note: Please select free instance if you are new to AWS

OAuth2 Authorization Grants

Ramu Ummadishetty — Sun, 31 Jan 2021 11:48:49 +0000

What is OAuth?

OAuth is an open standard used for authorization;i.e to grant access to data or functionality etc without having to deal with the original authentication.

Authentication vs Authorization

Authentication is confirming your own identity whereas authorization is giving access to the system.

Different type of Authorization Grants

There are four Authorization Grant type and used in different contexts
Authorization code: used for backend web apps
Implicit: used for SPA applications executing on the browser
Client credentials: used for machine to machine authentication of service accounts
Resource owner password credentials: used for highly trusted applications

Actors in OAuth2.0 workflow

User/Resource Owner: end-user;i.e. owner of a user resource
User-Agent/Device: Browser or native application
Client Application:API's;i.e. application that is attempting to get access to the user's account. The application could be a website, mobile app, etc
Authorization Server: The server where the client applications are registered. Issued an access token to the client app.
Resource Server: Which hosts the secured and protected user resources on appropriate access token it shares the user resources.

Workflow of Authorization Code Grant Type

remaining coming soon ...

Forem: Ramu Ummadishetty

Token vs Session Based Authentication

Session based authentication

Token based Authentication

Token auth flow

Token security

JSON Web Tokens

Header

Payload

Signature

HMAC and RSA

NGINX

Installing in Debian/Ubuntu Machine

Installing from Ubuntu repository

Uninstalling Nginx

Installing from Official Nginx repository

Key nginx folders,files,cmds

Python UNIT Testing

UNIT Testing

Test Scenario vs Test Case vs Test Suite

Implementing Python Unit testing

Note

AMI=Amazon Machine Image,Custom AMI

AWS Creating an EC2 Instance

Ramu Ummadishetty ・ Jun 23 ・ 2 min read

EBS-Elastic Block Store, Creating Additional Volume,Snapshots

Creating additional volume

AWS Creating an EC2 Instance

Ramu Ummadishetty ・ Jun 23 '21

Making disk usable

Unmount additional volume

Snapshot of EBS volume

AWS Creating an EC2 Instance

OAuth2 Authorization Grants

What is OAuth?

Authentication vs Authorization

Different type of Authorization Grants

Actors in OAuth2.0 workflow

Workflow of Authorization Code Grant Type