smsremind

Sends SMS reminders for calendar events.

When executed it loads a list of events within a specific range (see --offset argument) from a CalDav server. It can filter by calendar names (see --calendars) and inspects the event properties (summary, description and comment) for phone numbers. If an event includes a phone number, an sms is sent with a customizable message (see --sms-template).

Environment variables

The program expects the following environment variables.

• ASPSMS_USERKEY: ASPSMS User Key → www.aspsms.at/
• ASPSMS_PASSWORD: ASPSMS API password
• CALDAV_APPLEID: The Apple ID for the CalDav server
• CALDAV_PASSWORD: The app-specific password for the CalDav server → https://support.apple.com/en-us/102654

Example

Common use cases is to execute the program everyday at 9AM to check if there are events for tomorrow (--offset=1). If that's the case, send an reminder for the event with a custom message including the start time.

ASPSMS_USERKEY=...$ \
ASPSMS_PASSWORD=... \
CALDAV_APPLEID=test@example.com \
CALDAV_PASSWORD=... \
go run main.go \
    --offset=1 \
    --calendars="My Private Calendar" \
    --caldav=https://caldav.icloud.com/ \
    --sms-template="Reminder: Your appointment with me is tomorror at {{.StartTime}}. See you!" \
    --sms-sender="Your Friend"

DISCLAIMER: Some of the code was written by ChatGPT.

How to configure your Linux server to run.

Configurate a service

1. Create a dedicated smsremind user.

sudo useradd \
  --no-create-home \
  --shell /usr/sbin/nologin \
  smsremind

2. Create the runit service smsremind:

Store the environment variables

/etc/sv/smsremind/env/
├── ASPSMS_USERKEY
├── ASPSMS_PASSWORD
├── CALDAV_APPLEID
└── CALDAV_PASSWORD

3. Edit the run file for the service

#!/bin/sh -e
exec 2>&1

# Wait until 9AM
snooze -H9

# Run smsremind as user "smsremind"
exec chpst -e env -u smsremind /root/go/bin/smsremind \
    --offset=1 \
    --calendars="My Private Calendar" \
    --caldav=https://caldav.icloud.com/ \
    --sms-template="Reminder: Your appointment with me is tomorror at {{.StartTime}}. See you!" \
    --sms-sender="Your Friend"