Google Sheet to Calendar Feed

A service that reads events from a Google Sheet and publishes them as an ICS calendar feed that syncs with Apple Calendar, Google Calendar, and other calendar apps.

Configuration

Environment variables:

• PORT: Server port (default: 8080)
• BASE_URL: Base URL for calendar links (default: http://localhost:8080)
• SHEET_RANGE: Sheet range to read (default: Events!A:H)
• TEMPLATE_COPY_URL: URL to Google Sheets template copy link (sample)

Sheet Format

Setup Sheet

• B1: Timezone (IANA name, e.g., Europe/Helsinki)

Events Sheet (A:H)

• A: Event name (required)
• B: Date (required) - e.g., 2026-01-10 or 10.01.2026
• C: Time (optional) - e.g., 14:00 (defaults to 09:00)
• D: Duration (optional) - e.g., 60, 90m, 1:30 (defaults to 60m)
• E: Recurring (optional) - daily, weekly, biweekly, monthly, none
• F: End Date (optional) - for recurring events (inclusive, end-of-day local)
• G: Address (optional) - event location
• H: Description (optional) - event details

API Endpoints

• GET / - Index page
• POST / - Verify sheet and generate calendar link
• GET /cal/{sheetId}.ics - Calendar feed (cached 55 seconds)

Building and Running

# Build the application
go build -o calendar ./cmd/main.go

# Run locally
PORT=8080 BASE_URL=http://localhost:8080 ./calendar

# Or use environment variables for production
PORT=3000 BASE_URL=https://yourdomain.com TEMPLATE_COPY_URL=https://... ./calendar

Testing

Comprehensive unit tests with mocks provide 82.4%+ coverage of core logic.

# Run all tests
go test ./internal/...

# Run tests with verbose output
go test -v ./internal/...

# Run tests with coverage report
go test -cover ./internal/...

# Run specific package tests
go test -v ./internal/app
go test -v ./internal/utils
go test -v ./internal/sheet

# Detect race conditions
go test -race ./internal/...

# Run with coverage percentage by function
go test -coverprofile=coverage.out ./internal/...
go tool cover -html=coverage.out