Dumb UPS Auto Shutdown (D.U.A.S.)

Note check BlackoutDefender for a simpler approach.

As the name suggests, this is a script that can be used to auto shutdown a server if using a dumb UPS in case of a power outage. This is achieved by simply pinging a host on your network which does not have power backup and will immediately shut down in case of a power outage.

Config File

You can either compile the binary along with the config file or you can compile with an empty config file and then specify it through the --config flag to the binary. I haven't written documentation for the config file but, you can read the schema.json in the meantime. Here's an example:

{
  // define a node and give it any name you like, it's name will be used in the logs.
  "raspberry_pi": {
    // this is a required parameter for every host declared, it can be one of ipv4/ipv6/hostname/idna-hostname
    // if a node has errors in config, it'll be disabled and the other nodes will be used 
    "location": "10.0.3.14",
    // This host will be checked via ping
    "ping": {
      "retry_limit": 10
    },
    // Check methods are executed in the order you define them, this also applies to nodes.
    "https": {
      // this will check if the string "It works!" is present in the response body.
      "response_data": "It works!"
    }
  }
}

Usage

usage: duas [-h] [-c CONFIG] [-l LOG_FILE] [--log-level {DEBUG,INFO,WARNING,ERROR,CRITICAL}] [-f LOG_FORMAT] [-d DATE_FORMAT] [-i INTERVAL] [--dry-run]

Signals an auto shutdown for a device connected to a dumb UPS by checking other network devices that shut down in case of a power outage

options:
  -h, --help            show this help message and exit
  -c CONFIG, --config CONFIG
                        Path to the config file
  -l LOG_FILE, --log-file LOG_FILE
                        Path to the log file
  --log-level {DEBUG,INFO,WARNING,ERROR,CRITICAL}
                        Recommend level is INFO
  -f LOG_FORMAT, --log-format LOG_FORMAT
                        See python's logging module docs for help
  -d DATE_FORMAT, --date-format DATE_FORMAT
                        The date format in logs, see python's logging module docs for help
  -i INTERVAL, --interval INTERVAL
                        Amount of time to wait after a successful healthcheck.
  --dry-run             Testing mode, will not shutdown server but will create a log

Installation

Run the following commands on any machine, not necessarily on the machine you wish to run the script on.

git clone https://github.com/sujaldev/duas/
cd duas
virtualenv venv
source venv/bin/activate
pip install -r requirements.txt pyinstaller

Build

Before you build the binary you can define a duas.conf.json in the src/ directory

cd src
pyinstaller --onefile --name duas --add-data=duas.conf.json:. --add-data=schema.json:. main.py

A binary file will be created: src/dist/duas

Systemd

Once you have built the file, copy it to the machine you intend to shut down during a power outage. Then you can copy the src/sample.service file to any systemd location such as /etc/systemd/system/duas.service or ~/.config/systemd/user depending on what user you want to run the service under. Update the value of ExecStart to match the actual path of the binary and pass any extra parameters if you wish (run /path/to/binary --help).

Reload systemd by running:

systemctl daemon-reload

Start the service and enable it:

sudo systemctl enable --now duas.service

# or if you placed the service file under ~/.config
systemctl --user enable --now duas.service