Slack Gantt Chart Generator

A Slack app that automatically generates Gantt chart images from Slack Lists and displays them in a Canvas.

Features

• Manual Trigger: Use /gantt command to generate charts on demand
• Optional Polling: Auto-refresh chart at configurable intervals
• Extensible: Supports color-coding by category and visual grouping
• Clean Design: Modern, readable Gantt charts using matplotlib

Note: Slack Lists does not currently emit events to the Events API, so real-time automatic updates aren't possible. Use the /gantt command or enable polling for periodic updates.

Setup

1. Create a Slack App

1. Go to api.slack.com/apps and create a new app

2. Under OAuth & Permissions, add these Bot Token Scopes:

   • lists:read - Read list data
   • files:write - Upload chart images
   • canvases:write - Update canvases
   • canvases:read - Read canvas info
   • chat:write - Post messages
   • commands - Slash commands

3. Under Event Subscriptions:

   • Enable events
   • Set Request URL to https://your-app.onrender.com/slack/events (for HTTP mode)
   • Subscribe to bot events:
     • app_home_opened (optional, for App Home tab)

4. Under Slash Commands, create /gantt pointing to https://your-app.onrender.com/slack/commands

5. Install the app to your workspace

2. Environment Variables

# Required
SLACK_BOT_TOKEN=xoxb-your-bot-token
SLACK_SIGNING_SECRET=your-signing-secret

# For Socket Mode (development)
SLACK_APP_TOKEN=xapp-your-app-token

# Target resources
SLACK_LIST_ID=your-list-id
SLACK_CANVAS_ID=your-canvas-id
SLACK_CHANNEL_ID=your-channel-id

# Chart configuration (optional)
CHART_WIDTH=14
CHART_HEIGHT=8
CHART_DPI=150
CHART_TITLE=Project Timeline
CHART_GROUP_BY=category  # Group tasks by this field

# Category colors (optional)
CATEGORY_COLORS=development:#3498db,design:#9b59b6,testing:#27ae60

# Server
PORT=3000
DEBUG=false
DEBOUNCE_SECONDS=5

3. Get List and Canvas IDs

List ID: Open the list in Slack, click the three dots menu → "Copy link". The ID is in the URL.

Canvas ID: Open the canvas, click share → "Copy link". The ID is in the URL.

4. Deploy

Option A: Render (Recommended - Free Tier)

1. Fork this repo to your GitHub
2. Go to render.com and create a new Web Service
3. Connect your GitHub repo
4. Render will detect render.yaml automatically
5. Add environment variables in the Render dashboard

Option B: Local Development

# Create virtual environment
python -m venv venv
source venv/bin/activate  # Linux/Mac
# or: venv\Scripts\activate  # Windows

# Install dependencies
pip install -r requirements.txt

# Set environment variables (create a .env file)
cp .env.example .env  # Edit with your values

# Run with Socket Mode
python app.py

Slack List Format

Your Slack List should have these columns:

Column	Description	Required
Name/Title	Task name	Yes
Start Date	When task begins	Yes
End Date	When task ends	No (defaults to start)
Category	For color-coding	No
Group	For visual grouping	No

Usage

Manual Generation

Use the slash command in any channel:

/gantt              # Use configured list
/gantt <list_id>    # Use specific list

Automatic Polling (Optional)

Set POLL_INTERVAL_MINUTES in your environment to auto-refresh:

POLL_INTERVAL_MINUTES=30  # Refresh every 30 minutes

Customization

Colors by Category

Set CATEGORY_COLORS environment variable:

CATEGORY_COLORS=development:#3498db,design:#9b59b6,testing:#27ae60,done:#27ae60

Grouping Tasks

Set CHART_GROUP_BY to group tasks by a list column:

CHART_GROUP_BY=category
# or
CHART_GROUP_BY=phase

Architecture

app.py              # Main entry point, event handlers
config.py           # Configuration management
models/
  task.py           # Task data model
services/
  list_service.py   # Fetch Slack List data
  chart_service.py  # Generate Gantt charts
  canvas_service.py # Upload images, update Canvas
utils/
  date_utils.py     # Date parsing helpers

Troubleshooting

Chart not generating?

• Check that the bot is added to the channel
• Verify the SLACK_LIST_ID is correct
• Check logs for API errors

No tasks showing?

• Ensure your list has Start Date field populated
• Check date format (ISO 8601 works best)

Permission errors?

• Verify all required scopes are added
• Reinstall the app after adding scopes

License

MIT