simple-server-monitoring-action

Below is an example YAML file for this action

name: simple-server-monitoring

on:
  schedule:
    - cron: "0 * * * *"  # trigger this action every 1 hour

env:
  SLACK_WEBHOOK: ${{ secrets.SLACK_WEBHOOK }} 

jobs:
  server-monitoring:
    runs-on: ubuntu-latest
    name: server-monitoring using http request
    steps:
      - name: Checkout
        uses: actions/checkout@v3
      - name: Check request
        uses: jcy0308/[email protected]
        with:
          filename: './urls.json'
          protocol: 'https'
          slack: ${{ env.SLACK_WEBHOOK }}
          reposlack: 'encoded url'

Description

This GitHub Action parses a JSON file, send requests to hosts in JSON file, alert using slack api if host's response status code is not what expected.

Background : Services that handle large-scale traffic mostly have the capability to monitor the server's status in real-time and possess their own recovery solutions. On the other hand, for services created as personal projects or those anticipating low levels of traffic, real-time server monitoring is often not implemented. However, even for small-scale services, if a user requests the service and the server doesn't respond due to issues, it can lead to a significant decrease in trust in the service.

Therefore, using GitHub Actions to periodically send requests to the server and check its status can allow small-scale services to implement a server monitoring system with minimal effort and cost.

Points of Consideration

• In GitHub's billing policy, the free plan is limited to 2000 minutes per month. Since the intention of the action is to conduct cost-effective server monitoring, minimizing the execution time of the action is mandatory.

• Docker image optimzation

  • To reduce the Docker image size, we choosed an ultra-light Alpine image instead of the standard Node image. While the base Node image is around 950MB for Node 18, the Alpine image weighs in at approximately 178MB.

  • Additionally, we minimized dependencies to decrease installation time during execution. Here is most popular http request library in npm

library	weekly-download	bundle-size	avg-request-time
request	19,535,286	209KB	0.92
got	11,00,285	192KB	1.18
axios	9,759,583	346KB	0.84
superagent	3,469,000	196KB	0.89
node-fetch	2,443,184	62.6KB	0.89

• We choosed the npm-fetch-api over the request library to achieve the smallest bundle size while maintaining reasonable request delay.

• There are APIs that support both HTTP and HTTPS requests, as well as APIs that only accept either HTTP or HTTPS. Especially in cloud service environments, allows https protocol only. Therefore, we have set HTTPS as the default request, and by configuring environment variables, we have enabled sending requests using HTTP as well

Requirements

• A SLACK_WEBHOOK URL to send a message when something goes wrong
  • SLACK_WEBHOOK using Github_Secret
  • or Raw Url string inside your action.yml
• A JSON file of URLs in your repository that uses the following structure

JSON File

[
    {
        "host": "google.com",
        "method": "GET",
        "status": 200
    },
    {
        "host": "somehost.api.login",
        "method": "POST",
        "status": 201,
        "body": {
            "id":"admin",
            "password":"1234"
        }
    }
]

Supported REST API

• GET POST DELETE PUT

Environment Variables

This Action uses these environment variables

• SLACK_WEBHOOK is one you need to provide

See if you are using raw URL

If you directly upload a Slack URL to a GitHub repository, Slack might detect it as potentially compromised and invalidate the existing URL, generating a new one. Therefore, if you want to include a URL in your repository, you can encode it first and then include it in the action.yml file. The decoding process will be implemented within the action itself.

You can perform the encoding right here. Please provide the Slack URL you'd like to encode, and I'll help you with the encoding process.