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Overview

GitHub Actions allows you to run the WhatsApp attendance bot automatically on a schedule without any server infrastructure. This guide walks you through setting up the workflow.

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Workflow Structure

The bot uses a GitHub Actions workflow file located at .github/workflows/main.yml. Here’s the complete configuration:
main.yml
name: Registro WhatsApp Automático

on:
  schedule:
    # IMPORTANTE: Los horarios son en UTC. 
    # Para México (CST): 9:00 AM es 15:00 UTC | 3:00 PM es 21:00 UTC
    - cron: '0 15 * * 1-5'  # Lunes a Viernes 9:00 AM
    - cron: '0 21 * * 1-5'  # Lunes a Viernes 3:00 PM
  workflow_dispatch: # Permite ejecutarlo manualmente para probar

jobs:
  run-bot:
    runs-on: ubuntu-latest
    steps:
      - name: Checkout code
        uses: actions/checkout@v3

      - name: Set up Python
        uses: actions/setup-python@v4
        with:
          python-version: '3.9'

      - name: Install dependencies
        run: pip install requests

      - name: Execute Script
        env:
          INSTANCE_ID: ${{ secrets.INSTANCE_ID }}
          TOKEN: ${{ secrets.TOKEN }}
          GROUP_ID: ${{ secrets.GROUP_ID }}
        run: python bot.py

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Understanding the Schedule

1

Cron Syntax

The workflow uses cron expressions to schedule executions:
  • 0 15 * * 1-5 - Runs at 15:00 UTC (9:00 AM CST) Monday through Friday
  • 0 21 * * 1-5 - Runs at 21:00 UTC (3:00 PM CST) Monday through Friday
Cron format: minute hour day-of-month month day-of-weekGitHub Actions uses UTC timezone by default, so you’ll need to convert your local time.
2

Time Zone Conversion

Calculate your UTC offset:
TimezoneOffset9:00 AM Local3:00 PM Local
CST (Mexico)UTC-615:00 UTC21:00 UTC
PSTUTC-817:00 UTC23:00 UTC
ESTUTC-514:00 UTC20:00 UTC
GMTUTC+009:00 UTC15:00 UTC
Remember to account for Daylight Saving Time changes in your region.
3

Manual Trigger

The workflow_dispatch event allows manual execution:
  1. Go to your repository on GitHub
  2. Click Actions tab
  3. Select Registro WhatsApp Automático workflow
  4. Click Run workflow button
  5. Select branch and click Run workflow
This is useful for testing without waiting for the scheduled time.

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Adding GitHub Secrets

The workflow requires three secrets to authenticate with the UltraMsg API:
1

Navigate to Settings

  1. Go to your GitHub repository
  2. Click Settings tab
  3. In the left sidebar, expand Secrets and variables
  4. Click Actions
2

Add Required Secrets

Click New repository secret and add each of these:
Your UltraMsg instance ID (e.g., instance12345)
Secrets are encrypted and only exposed to the workflow during execution. They never appear in logs.
3

Verify Secret Names

Ensure your secret names match exactly what’s in the workflow:
env:
  INSTANCE_ID: ${{ secrets.INSTANCE_ID }}
  TOKEN: ${{ secrets.TOKEN }}
  GROUP_ID: ${{ secrets.GROUP_ID }}
Secret names are case-sensitive.

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Workflow Jobs Breakdown

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Environment Setup

The workflow runs on ubuntu-latest and performs these steps:
  1. Checkout code - Downloads your repository code using actions/checkout@v3
  2. Set up Python - Installs Python 3.9 using actions/setup-python@v4
  3. Install dependencies - Runs pip install requests to install the required library
  4. Execute script - Runs python bot.py with environment variables from secrets

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Environment Variables

The secrets are injected as environment variables: 
env:
  INSTANCE_ID: ${{ secrets.INSTANCE_ID }}
  TOKEN: ${{ secrets.TOKEN }}
  GROUP_ID: ${{ secrets.GROUP_ID }}
These are accessed in bot.py using: 
instance_id = os.getenv('INSTANCE_ID')
token = os.getenv('TOKEN')
group_id = os.getenv('GROUP_ID')

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Modifying the Schedule

To change when the bot runs, edit the cron expressions: 
schedule:
  - cron: '0 14 * * 1-5'  # 8:00 AM CST
  - cron: '0 22 * * 1-5'  # 4:00 PM CST
Use crontab.guru to validate your cron expressions, but remember to convert to UTC.

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Monitoring Workflow Executions

To view workflow runs:
  1. Go to the Actions tab in your repository
  2. Click on a workflow run to see details
  3. Expand the Execute Script step to see the bot’s output
  4. Check for the status code and API response
Successful executions show: 
Status: 200, Response: {"sent":"true","message":"ok"}
If you see errors like Status: 401, verify your secrets are set correctly. If you see Status: 404, check your instance ID and group ID.

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