Automatically receive messages in discord when a platform is down

Hello everyone! In this blog, we will look at how to automate the process of getting notified in discord if a platform's status is down. It is very helpful as it notifies developers in discord when their website is down. We will learn about the following topics in this blog:

Using DevOps utilities like webhooks, cron jobs, SSH
Automating deployment to a remote host like an Amazon EC2 Instance

Requirements

Anyone with a basic knowledge of any coding languages can follow along with this blog. Having a basic knowledge of Git is recommended as well.

Make the Script

Firstly, we need to make the script we want to run. The script will be a simple Node.js platform status checker running regularly in the background and report to Discord if any of the platforms are down. You can make any script you want. Of course, absolute beginners are urged to follow along with the blog.

Webhook

We will use a webhook to message us in discord if any of our servers are down. A webhook is an HTTP-based callback function that allows lightweight, event-driven communication between 2 application programming interfaces (APIs). You can learn more about it here.

To create a webhook for a discord server go to a Discord server's settings and follow the path of "Apps > Integrations > Webhooks > New Webhook". The webhook should be created now. Click on it and then click on "Copy Url" as we need it to send messages to discord.

We also have to make HTTP requests in our script. There are a lot of packages available in NPM but I will go with node-fetch in this tutorial. The node-fetch package only needs to be installed if your node version is less than 18 as it is build into node otherwise. We will install it by using the following command:

npm install node-fetch

Make the script:

import fetch from "node-fetch"
async function postplatformstatus() {
  const allPlatforms = [
    // use any urls and check their status 
    'https://api.reinforz.ai/ping',
    'https://app.reinforz.ai',
    'https://reinforz.ai',
  ];
  const messages = []; // array containing the messages to send
  for (const platform of allPlatforms) {
    const response = await fetch(platform);
    // We will only notify people if an error has occurred
    if (response.status >= 400) {
      // If the status code sent by the response is 400 or higher,
      // then it means an error is happening and we will notify relevent people with the platform 
      const singleMessage = `${platform} is down. Status: ${response.status} 🔴`
      // If any error response is recieved add it to messages
      console.log(singleMessage);
      messages.push(singleMessage);
    }
  }
  const ROLE_ID = '<copy a role Id from discord>';
  if (messages.length !== 0) {
    // use the send a message to discord using the webhook URL to see if which servers are inactive.
    await fetch(
      '<the copied webhook url>',
      {
        method: 'POST',
        headers: {
          'Content-Type': 'application/json',
        },
        body: JSON.stringify({
          // <@ROLE_ID> is used to notify members with a specific discord role
          content: `<@&${ROLE_ID}>\n${messages.join('\n')}`,
        }),
      }
    );
  }
}

postplatformstatus();

Note: Make an empty GitHub repository and push the new repository changes.

Make the AWS EC2 instance

We need a remote host to deploy the script. We are going to use an Amazon EC2 instance for this. It's important to note that while EC2 is a popular choice for hosting virtual machines in the cloud, you can use other hosting providers if you prefer. Creating an EC2 instance involves several steps, which are explained in the official AWS documentation. In general, you will need to select an instance type and size that meets your computing needs, configure your security and networking settings, and then launch the instance. Once your instance is running, you can connect to it using SSH or other remote access tools.

Setup the AWS EC2 instance

Logging in

After the EC2 instance is up and running, we need to be able to log in to it on our local machine. We will use SSH to establish a cryptographic network protocol to securely connect to our remote host. To connect to the EC2 instance using SSH, you will need to do the following:

Download and install an SSH client on your local computer. If you are using a Mac or Linux system or the latest Windows versions, you can use the built-in terminal and SSH command. Older Windows users can use a program like PuTTY.
Locate your EC2 instance's public DNS or IP address. You can find this information in the EC2 Management Console, or by using the ec2-describe-instances command if you are using the AWS CLI.
Use the SSH client to connect to your EC2 instance. The exact command will vary depending on your client and the operating system of your EC2 instance. For example, on a Linux or Mac system you can use the following command:
```
ssh -i /path/to/your/private/key.pem ec2-user@your-instance-public-ip
```
If this is your first time connecting to the instance, you may be prompted to add the host key to your local SSH known_hosts file. Type yes and press enter to continue.

You should now be logged in to your EC2 instance and able to run commands on the remote system. It's important to note that the exact steps and commands may vary depending on the specific setup of your EC2 instance and your local computer. If you are having trouble connecting, you can check the official AWS documentation or seek help from a qualified AWS professional.

Also, to use the command without linking the /path/to/your/private/key.pem every time like:

ssh ec2-user@your-instance-public-ip

Add or Edit the following into the config file in your .ssh folder

Note: The path of the file is C:\Users\<Username>\.ssh\config in Windows.
Host <your-instance-public-ip>
    HostName <your-instance-public-ip>
    User ec2-user
    IdentityFile "/path/to/your/private/key.pem"

To get the private key .pem file that is used in the config file, the SSH connection process, you will need to do the following:

In the EC2 Management Console, go to the Key Pairs section under the Network & Security menu.
Click on the Create Key Pair button and give your key pair a name. This will download the private key .pem file to your local computer.
Save the .pem file in a safe and secure location on your local computer. You will need this file to connect to your EC2 instance using SSH.

It's important to note that the private key .pem file is essential for accessing your EC2 instance. You should treat it like a password and keep it safe and secure. If you lose the .pem file, you will not be able to connect to your EC2 instance. You should also never share your .pem file with anyone else, as it gives them access to your EC2 instance.

Set up node

Set up the softwares needed to run your script. I am using node so I will install it. First, I will install Node Version Manager (NVM). It is a command-line utility that allows you to install and manage multiple versions of the Node.js JavaScript runtime on a single computer. We are using NVM to allow our remote host to be able to run other Node.js programs if they require different node versions.

curl -o- https://raw.githubusercontent.com/nvm-sh/nvm/v0.39.2/install.sh | bash

Note: This will install version 0.39.2, to get the updated one go to this link: github.com/nvm-sh/nvm#installing-and-updating.

Next, we will install the 16.x version of Node with the command nvm install 16. Afterwards, verify if node and npm are installed using the commands node -v and npm -v in the terminal of the EC2 instance. If node and npm are not being recognized do the following:

for node:

sudo ln -s /home/<my_user>/.nvm/versions/node/<my_node_version>/bin/node /usr/bin/node

for npm:
```
sudo ln -s /home/<my_user>/.nvm/versions/node/<my_node_version>/bin/npm /usr/bin/npm
```
The above commands link the actual node and npm scripts to /usr/bin/ because bash recognizes scripts from there.

Cron job in EC2 instance

We will now set up a cron job to run on our server. Cron jobs are a standard method of scheduling tasks to run on a machine. Cron is a service running in the background that will execute commands (jobs) at a specified time, or at a regular interval. More details about it can be found here.

Type the following in the terminal to setup a cronjob:

crontab -e

Add the following in a new line and save and exit the file using :wq:

*/7 * * * * bash /home/myCronScript.sh

This runs the script /home/myCronScript.sh every 7 minutes. Of course, we don't have the bash script now. So let's set them up next.

Adding scripts

We need two bash scripts in our EC2 instance: One for the cron job discussed above and another for the Deployment Script. Deployment to a production server typically involves a number of steps, such as building and packaging the application, transferring the package to the production server, and configuring the server to run the application. We need the deployment script to automate installing dependencies on our production server so that it runs without issues.

The cron script in /home/myCronScript.sh:

#!/bin/bash
RED='\033[0;31m'
NC='\033[0m'

cd /home/platform-status

if ! (node /home/platform-status/index.js) then
  printf "${RED}Failed to run platform status checker${NC}\n"
  exit 1
fi

The deployment script in /home/myDeployScript.sh:
```
#!/bin/bash
RED='\033[0;31m'
NC='\033[0m'

cd /home/platform-status

if ! (npm install --production) then
  printf "${RED}Failed to install dependencies${NC}\n"
  exit 1
fi
```
Deploy to EC2 instance

Finally, we have to find a way to upload to the remote server and run the deploy script automatically. One way to do them is to use GitHub Actions. GitHub Actions is a continuous integration and continuous delivery (CI/CD) platform that allows us to automate our build, test, and deployment pipeline. Check out their documentation if you want to know more about it.

We are going to add a simple GitHub action to automate deploying to our EC2 instance. Add new folders .github\workflows\ in the project directory and put a .yml file on the path, .github\workflows\deploy.yml, and add the following to it:

name: Deploy Script

# run the deployment process if any changes come to a js file
on:
  push:
    branches:
      - 'master'
    paths:
      - '**.js'
      - '**.json'

jobs:
  deploy:
    runs-on: ubuntu-latest

    steps:
    - name: Checkout branch
      uses: actions/checkout@v1

    # upload to the ec2 host
    - name: Upload to Server
      uses: easingthemes/ssh-deploy@main
      env:
        SSH_PRIVATE_KEY: ${{ secrets.SSH_PRIVATE_KEY }}
        ARGS: "-rltgoDzvO --delete"
        SOURCE: ""
        REMOTE_HOST: ${{ secrets.REMOTE_HOST }}
        REMOTE_USER: ${{ secrets.SSH_USERNAME }}
        TARGET: "/home/platform-status/"
        EXCLUDE: "/node_modules/, /.github/, /.gitignore, /README.md"

    # deploy to the ec2 host
    - name: Deploy to production
      uses: appleboy/ssh-action@v0.1.2
      with:
        host: ${{ secrets.REMOTE_HOST }}
        key: ${{ secrets.SSH_PRIVATE_KEY }}
        username: ${{ secrets.SSH_USERNAME }}
        script: |
          bash /home/myDeployScript.sh

As you may have noticed, we need to add the secrets of our EC2 instance to our GitHub repository to make this GitHub Action work. Otherwise, it will not know where our server is. To add the secrets go to your repository, and follow the path: settings > secrets > actions. Then, click on New Repository Secret and add the following secrets:

REMOTE_HOST: the IP address of your remote host
SSH_PRIVATE_KEY: the private key needed to ssh into the server
SSH_USERNAME: the username of the user on the remote machine.

Finally, commit and push all your changes and observe the GitHub action running in GitHub. It should run and end successfully.

Conclusion

Thank you for reading! The github repository for containing the blog is: github.com/Reinforz/platform-status-blog. If you have any questions or face any problems while doing the steps written in this blog, don't hesitate to comment down below. Also, check out our website at reinforz.ai.

Written by Rafid Hamid

Reinforz