Forem: Akhilesh Thite

How to keep EC2 instance running after SSH is terminated?

Akhilesh Thite — Tue, 05 Apr 2022 09:59:28 +0000

In this blog post, I'm going to list a few commands that will help you to keep the EC2 instance running after SSH is terminated.

Author

Akhilesh Thite

Linux & Mac users

First, Log in to the server with your SSH key.

To keep the server running in background, use the following command.

screen -d -m

Let's assume you have a python web application, then your command would look like this:

screen -d -m python app.py

Or if you're using node, then your command would look like this:

screen -d -m npm start

To list the available screens, use the following command.

screen -ls

To restart the session, use the following command.

screen -r [session restart]

To quit the session, use the following command.

screen -X -S [session you want to kill] quit

Windows (PuTTY) users

First, SSH into your remote box. Type screen, then start the process you want.

Press Ctrl-A then Ctrl-D. This will detach your screen session but leave your processes running. Now, you can log out of the remote box.
If you want to come back later, log on again and type screen -r, this will resume your screen session and you can see the output of your process.

Have any questions or suggestions? Leave a comment down below.
Thank you!

DHost: Publish static websites right from VS Code!

Akhilesh Thite — Tue, 15 Mar 2022 14:03:56 +0000

DHost VS Code Extension allows you to instantly publish static websites to IPFS by using web3.storage.

The idea was to build a decentralized dev tool that can instantly publish websites from VS Code without any third-party centralized cloud services. Now, with DHost you can publish and share your websites quickly right from VS Code with anyone in the world!

💻 Install extension from here

Features

✅ Decentralized
✅ Instant hosting (Publish your website with just 2 commands)
✅ Unlimited uploads
✅ Accessible to anyone
✅ Permanent storage (web3.storage helps to permanently pin your content)
✅ Secure (Share IPFS links instead of IP Address and host for development)
✅ Free to use

DHost even supports build directory uploads (production build of the app made with react.js, vue.js, etc.)

Steps to use

Open command palette

Windows & Linux: Ctrl + Shift + P
MacOS: Command + Shift + P

1. Select the folder

Select the folder of your static website by dhost.select command.

After selecting the folder, the "Folder selected!" popup will appear.

2. Publish to IPFS

Now, publish your static website by dhost.publish command.

It'll take a few seconds to publish.

After publishing successfully, it'll show the IPFS CID of your website and an option to open the website (IPFS gateway URI).

If you have any queries, then create a discussion thread.

Working

DHost uses web3.storage, basically it makes the content available over IPFS and permanently pins the content with the help of Filecoin infrastructure. Read more about web3.storage and how it works here.
We have our separate DHost API Token on web3.storage, it allows up to 1TB of content pinning, after that we can request more storage for our respective use.

After uploading your website to IPFS, web3.storage returns a CID Qmeq5NxNX644KHNji.., which is a hash for an array of files stored on IPFS, and that later is combined with IPFS gateway link https://ipfs.infura.io/ipfs/ to access the website.

Links

💻 VSCode Marketplace: https://marketplace.visualstudio.com/items?itemName=DHost.dhost
👾 GitHub: https://github.com/buidltools/vscode-dhost

Built by ~ BUIDL Tools
🌐 Website: https://buidltools.com/
🐦 Twitter: https://twitter.com/buidltools

Thank you!

Get started with VR programming for Metaverse

Akhilesh Thite — Sat, 29 Jan 2022 12:33:42 +0000

Hey! It's Akhilesh here. This is gonna be a short post. So, I was wandering on GitHub and discovered A-Frame. It's a web framework for building VR (virtual reality) experiences.

Get started

To get started, first you have to import A-Frame library via external script tag.

<script src="https://aframe.io/releases/1.2.0/aframe.min.js"></script>

To create objects in VR, learn about their HTML primitives (a-scene, a-box, a-sphere, a-cylinder, a-sky, etc.) from here.

Here's a basic template to get started.

<html>
  <head>
    <script src="https://aframe.io/releases/1.2.0/aframe.min.js"></script>
  </head>
  <body>
    <a-scene>
      <a-box position="-1 0.5 -3" rotation="0 45 0" color="#4CC3D9"></a-box>
      <a-sphere position="0 1.25 -5" radius="1.25" color="#EF2D5E"></a-sphere>
      <a-cylinder position="1 0.75 -3" radius="0.5" height="1.5" color="#FFC65D"></a-cylinder>
      <a-plane position="0 0 -4" rotation="-90 0 0" width="4" height="4" color="#7BC8A4"></a-plane>
      <a-sky color="#ECECEC"></a-sky>
    </a-scene>
  </body>
</html>

Output:

Website: https://aframe.io/
GitHub: https://github.com/aframevr/aframe
Documentation: https://aframe.io/docs/1.2.0/introduction/

If you know any VR programming resources, then please feel free to comment down below, I would love to add them here with full credits.

Thank you!

How to contribute to open-source for the first time?

Akhilesh Thite — Fri, 28 Jan 2022 15:06:55 +0000

Introduction

Getting started with open source and want to make your first PR?
In this tutorial, we'll cover everything from git installation to git commands. Before we start, here's a quick intro to Git and GitHub.

GitHub is widely used code hosting platform in the world, where you can manage, collaborate and develop your software.

Git is version control system, that keeps track of every single commit or change you are making in a project.

Author

Akhilesh Thite

Git installation

Install Git from this link:- https://git-scm.com/downloads

To check the Git version

git --version

To set the global Git username & email address

git config --global user.name "your name"
git config --global user.email "your email"

Now that you've installed git on your local machine, you can start contributing! You can find a repository with "first-timers" issue tag, or here's a repository specifically made for first timers.

STEPS to contribute

Before you follow all these STEPS, make sure you fork the repository in your GitHub account.

1- Clone the repository using HTTPS or SSH (If you don't have 2FA enabled).
This will basically download the git initialized repository on your computer.

git clone https://github.com/<username>/<RepositoryName>.git

Personal Access Token (PAT) is required if you enable 2FA on your Github account [link]. For that, use the following command instead of the normal URL command.

git clone https://<GitHubToken>@github.com/<username>/<RepositoryName>.git

2. Create a new branch.
Creating a new branch allows you to isolate your changes from the master (main) branch. If your changes goes well, you always have the option to merge your changes into the master branch. If things don't go so well you can always discard the branch or keep it within your local repository.

git branch YourBranchName

3. Shift to your branch from master (main) branch.
By default you're on main branch. So to switch from main, use the following command.

git checkout YourBranchName

Make changes in the project.

4. Add all the changes you've made.

git add .

5. Make a commit message of the changes you've made. Learn more about conventional commits here.

git commit -m 'Add my contribution'

6. Shift to the master (main) branch.
Now, switch back to main branch to merge all the changes.

git checkout main

7. Merge everything from your branch to the master (main) branch.

git merge YourBranchName

8. Get ready to push from your local machine.
You cannot directly push the changes from your local machine, to do that we have to create a new connection record to a remote repository. After adding a remote, you'll be able to use as a convenient shortcut for in other Git commands.

If you don't have 2FA enabled, then use the normal HTTPS or SSH link.

git remote add <message> https://github.com/<username>/<RepositoryName>.git

Personal Access Token (PAT) is required if you enable 2FA on your Github account [link].
For that, use the following command instead of the normal URL command.

git remote add <message> https://<GitHubToken>@github.com/<username>/<RepositoryName>.git

9. Push everything on your forked repository.
This will push all the changes you've made to the master (main) branch of your forked repository.

git push -u <message> main

Now, click on Pull Request button, you'll have the option to create a pull request. i.e., <your forked repo> -> <original repo>, That's it you're done!

Thank you!

DScan: Decentralized QR code generator chrome extension

Akhilesh Thite — Tue, 30 Nov 2021 18:59:12 +0000

Introduction

DScan is a chrome extension that uploads the content to IPFS and generates decentralized QR codes. It is compatible with chromium-based browsers. Built by BUIDL Tools.

Benefits

DScan allows you to quickly upload files as well as folders to IPFS by using web3.storage and get a "decentralized QR code" with IPFS CID. Later you can share the QR code or hosted gateway link with everyone for easy and decentralized file sharing.

Benefits of DScan for file sharing:
✅ Decentralized storage
✅ Unlimited uploads
✅ Fast upload speed (will take around half hour to upload upto 1GB of data)
✅ Permanent pinning (web3.storage helps to permanently pin your content)
✅ Zero compression
✅ Private (Share QR codes or links instead of original data)
✅ Free to use
✅ User-friendly

Working

DScan uses web3.storage, basically it makes the content available over IPFS and permanently pins the content with the help of Filecoin infrastructure. Read more about web3.storage and how it works here.
We have our separate DScan API Token on web3.storage, it allows up to 1TB of content pinning, after that we can request more storage for our respective use.

After uploading the content to IPFS, web3.storage returns a CID Qmeq5NxNX644KHNjiWWbWTJHE94BQrXpMDqW4hVNs1WHrk, which is a hash for an array of files stored on IPFS (for files {wrapWithDirectory: false}), and that later is combined with IPFS gateway link https://dweb.link/ipfs/ to access the content.
QR code is generated with the help of IPFS gateway link https://dweb.link/ipfs/Qmeq5NxNX644KHNjiWWbWTJHE94BQrXpMDqW4hVNs1WHrk, which later you can scan.

Remember, anyone can access the content if they have your CID unless there is some encryption involved. So, make sure you save the CID securely for private uploading (we DO NOT recommend uploading confidential content). IPFS folks are currently working on the private network, read more about it here.

Use

Step 1: Install the extension from Chrome web store.

Step 2: Click on the "upload" button and select the file or folder you want to upload.

Step 3: It'll show generated QR code, IPFS CID, and hosted gateway link.

You can download the generated QR code and then, it's ready for scanning!
You also have an option to copy the CID and gateway URI.

Want to contribute?

Contributions are always welcome! Here are some issues to get started.

Links

💻 Extension: https://chrome.google.com/webstore/detail/dscan-decentralized-qr-co/idpfgkgogjjgklefnkjdpghkifbjenap
👾 GitHub: https://github.com/buidltools/dscan

Built by ~ BUIDL Tools
🌐 Website: https://buidltools.com/
🐦 Twitter: https://twitter.com/buidltools

Have any questions or suggestions? Leave a comment down below.
Thank you!

How to Deploy Smart Contracts on Polygon (Matic) Network? How to Handle Different Errors?

Akhilesh Thite — Sat, 07 Aug 2021 21:00:30 +0000

In this tutorial, we will cover how to deploy smart contracts to the Polygon (Matic) Mumbai test network. We'll cover some of the possible errors which might occur during the deployment. So, grab a cup of coffee ☕️ and follow the steps.

After this tutorial you will be able to:

Deploy the smart contracts on polygon (Matic) Mumbai Test Network.
Tackle the errors while deploying the smart contracts on polygon (Matic) Mumbai Test Network.

Author

Akhilesh Thite

1. MetaMask setup.

To deploy the smart contracts on Matic you first have to create a Matic network in MetaMask wallet.
Settings -> Networks -> Add network -> Save

To get test Matic for deployment and testing,
go to -> Matic Faucet -> Select Mumbai -> Paste wallet address -> Submit
Done! check your wallet, you'll see some Matic there.

2. truffle-config

truffle-config.js for Mac users
truffle.js for Windows users The truffle-config file is an important file to understand. In this file, we must configure the path to the DTube Solidity file (smart contract), the contract ABI, and define the available networks.

const HDWalletProvider = require("@truffle/hdwallet-provider")
require('dotenv').config(); // Load .env file

module.exports = {
  networks: {
   // For Ganache, your personal blockchain
   development: {
      host: "127.0.0.1",     // Localhost (default: none)
      port: 8545,            // Standard Ethereum port 
      network_id: "*",       // Any network (default: none)
    },
  },
  contracts_directory: './src/contracts/',
  contracts_build_directory: './src/abis/',
  compilers: {
    solc: {
      optimizer: {
        enabled: true,
        runs: 200
      }
    }
  }
}

Ensure you create an .env file in the project root directory (~/DTube/.env) and paste into it the Secret Recovery Phrase (12 words) of your preferably newly generated and testnet-only MetaMask wallet with the variable name MNEMONIC. This will be loaded by truffle at runtime, and the environment variable can then be accessed with process.env.MNEMONIC.

MNEMONIC= 12 secret words here..

Now, let's add matic network in our truffle-config file which will contain our environment variable MNEMONIC and RPC URL.

    matic: {
      provider: () => new HDWalletProvider(process.env.MNEMONIC, 
      `https://rpc-mumbai.matic.today`),
      network_id: 80001,
      confirmations: 2,
      timeoutBlocks: 200,
      skipDryRun: true,
      gas: 6000000,
      gasPrice: 10000000000,
    },

You can set the gas price and gas limits for faster transactions as shown in the above code block.

3. Deploy Smart Contracts

Command: truffle migrate --network matic
If you're deploying it second time then deploy with this command just to reset and avoid JSON errors.
Command: truffle migrate --network matic --reset
If everything worked fine, you'll see something like this:

2_deploy_contracts.js
=====================

   Replacing 'MyContract'
   ------------------
   > transaction hash:    0x1c94d095a2f629521344885910e6a01076188fa815a310765679b05abc09a250
   > Blocks: 5            Seconds: 5
   > contract address:    0xbFa33D565Fcb81a9CE8e7a35B61b12B04220A8EB
   > block number:        2371252
   > block timestamp:     1578238698
   > account:             0x9fB29AAc15b9A4B7F17c3385939b007540f4d791
   > balance:             79.409358061899298312
   > gas used:            1896986
   > gas price:           0 gwei
   > value sent:          0 ETH
   > total cost:          0 ETH

   Pausing for 2 confirmations...
   ------------------------------
   > confirmation number: 5 (block: 2371262)
initialised!

   > Saving migration to chain.
   > Saving artifacts
   -------------------------------------
   > Total cost:                   0 ETH


Summary
=======
> Total deployments:   2
> Final cost:          0 ETH

Code snippet from matic truffle docs.

4. Dealing with different errors

If you get any of these errors then follow these steps

Error:

Error: PollingBlockTracker - encountered an error while attempting to update latest block:

Fix_1:

Change https://rpc-mumbai.matic.today by using Infura custom RPC
infura -> Create new project -> Settings -> Endpoints -> Polygon Mumbai

    matic: {
      provider: () => new HDWalletProvider(process.env.MNEMONIC, 
      `https://polygon-mumbai.infura.io/v3/process.env.PROJECT_ID`),
      network_id: 80001,
      confirmations: 2,
      timeoutBlocks: 200,
      skipDryRun: true,
    },
  },

Paste your PROJECT_ID there from .env file.
truffle migrate --network matic --reset

If still dealing with error, try this 2nd fix.

Fix_2:

Change https://rpc-mumbai.matic.today by using Matic custom RPC

    matic: {
      provider: () => new HDWalletProvider(process.env.MNEMONIC, 
      `https://rpc-mumbai.maticvigil.com/v1/process.env.PROJECT_ID`),
      network_id: 80001,
      confirmations: 2,
      timeoutBlocks: 200,
      skipDryRun: true,
    },
  },

Paste your PROJECT_ID there from .env file.
truffle migrate --network matic --reset

Error:

*** Deployment Failed ***

"Migrations" -- only replay-protected (EIP-155) transactions allowed over RPC.

Fix:

npm install @truffle/hdwallet-provider@1.4.0
Truffle hdwallet-provider version 1.4.0 will fix this error.

Error:

Error:  *** Deployment Failed ***

"Migrations" -- Transaction was not mined within 750 seconds, please make sure your transaction was properly sent. Be aware that it might still be mined!.

Fix:

    matic: {
      provider: () => new HDWalletProvider(process.env.MNEMONIC, 
      `https://rpc-mumbai.maticvigil.com/v1/process.env.PROJECT_ID`),
      network_id: 80001,
      confirmations: 2,
      timeoutBlocks: 200,
      skipDryRun: true,
      networkCheckTimeout: 100000,
    },
  },

Just add networkCheckTimeout: 100000

If you discover any new errors and If you know the solution for it, then feel free to comment down below, I'll add that Error-Fix here

References

Truffle docs: https://www.trufflesuite.com/docs/truffle/overview
Polygon (Matic) docs: https://docs.matic.network/docs/develop/getting-started
GitHub repo: https://github.com/AkhileshThite/DTube