remindme_caldav

A Calendar Alerting Daemon

Purpose

This script is a simple calendar alerting daemon written in Python. It monitors .ics files for changes and sends alerts based on the events' start times, recurrence rules, and alert triggers defined within these files. The main purpose of this script is to provide reminders or notifications about upcoming events.

How it Works

The script works by parsing .ics files using the icalendar library, which converts them into a Python dictionary format for easier manipulation. It then processes each event and calculates when the next alert should be triggered based on the event's start time, recurrence rules, and alert triggers. If an alert is due to trigger, it sends a notification via email or XMPP (an instant messaging protocol).

The script also monitors for changes in the directory containing .ics files using the watchdog library. When a file is modified, created, or deleted, it updates its internal list of events accordingly.

How to Use It

This script should be used with a calendar syncing service such as vdirsyncer. vdirsyncer can be scheduled using cron to sync regularly from the CalDav server.

To use this script, you need Python 3 installed on your system. You can install the required libraries by running:

pip install -r requirements.txt

You also need a .toml configuration file with the following structure:

[app]
calendar_dir = "/path/to/your/ics/files"
email_address = "your-email@example.com"
smtp_server = "smtp.example.com"
smtp_port = 587
smtp_username = "your-username"
smtp_password = "your-password"
...

The config file is passed to the script with the --config argument.

You can then run the script with:

python3 remindme_caldav.py --config /path/to/your/config.toml

Installation

A Makefile and systemd service file is also included for Debian/Ubuntu based systems. Make sure to modify the config file in the source directory before installation. Also, please ensure that the calendar_dir exists and syncing from a CalDav server before running the script.

This Makefile does the following:

• install: Installs Python 3.11, creates a virtual environment in /opt/remindme_caldav/.venv, installs dependencies from requirements.txt into this virtual environment, copies the script to /opt/remindme_caldav/, copies the config file to /etc/remindme_caldav and sets up the systemd service file. It also sets up the logging dir in /opt/remindme_caldav/logs.

• uninstall: Stops and disables the systemd service, removes the installation directory (/opt/remindme_caldav/), and deletes the systemd service file.

Logging

The script uses Python's built-in logging module to handle logging. The setup_logging(log_location) function sets up basic configuration for the logger, including the log file location and format.

Log levels are used to categorize logs based on their severity: DEBUG, INFO, WARNING, ERROR, CRITICAL. By default, the log level is set to INFO. This can be modified by passing a --loglevel argument when running the script.

The setup_log_location(logdir) function sets up the locations for three types of logs: log, status, and alert_history.

• Log Location: This is where script logs are stored. These logs contain information about the general operation of the script, such as when it starts or stops, what files it's processing, errors etc. The logdir argument specifies the directory where these log files will be created.

• Status Location: This file contains information about the current state of each event being monitored by the script. It includes details such as the current time, the name of the event, its recurrence dates, and when the next alert will be triggered. The purpose of this file is to provide a real-time status update on what's happening in the script.

• Alert History Location: This file logs all alerts that have been sent out by the script. It includes details such as the timestamp when the alert was triggered, and the definition time of the alert. The purpose of this file is to keep a record of all alerts that have been sent.