Installation

Prerequistes

Geordi requires:

• Java 8 or higher (you can use OpenJDK or Oracle Java)
• Postgresql 9.3 or higher

Getting the Binary

You can download a precompiled geordi.jar file at GitHub. It is a static jar file that already contains Geordi and all the required libraries it depends on.

To build Geordi yourself, check out the project at GitHub and build it with maven (mvn clean install). You will then find the geordi.jar file in the target folder of your checkout.

For RedHat based systems, there is also a rpm file at GitHub. After installation, just edit the /etc/geordi.conf file and start Geordi via systemd as described below.

Database

Create a new Postgresql database for Geordi, then create the tables and sequences:

CREATE SEQUENCE ser_device;

CREATE TABLE device (
  id integer PRIMARY KEY DEFAULT nextval('ser_device'),
  name varchar(255) NOT NULL,
  type varchar(100) NOT NULL,
  cron varchar(50) NOT NULL,
  config json NOT NULL default '{}'
);

CREATE SEQUENCE ser_sensor;

CREATE TABLE sensor (
  id integer PRIMARY KEY DEFAULT nextval('ser_sensor'),
  device_id integer NOT NULL REFERENCES device,
  name varchar(255) NOT NULL,
  unit varchar(20) NOT NULL,
  config json NOT NULL default '{}'
);

CREATE TABLE sample (
  sensor_id integer NOT NULL REFERENCES sensor,
  time timestamptz NOT NULL,
  value decimal NOT NULL,
  UNIQUE(sensor_id, time)
);

The database will later contain the sensor configurations and the collected sensor data.

Starting Geordi

Start Geordi from the command line:

java -jar geordi.jar

By default, it will connect to a database called geordi on the local machine, without giving authentication. You can change this behavior either by command line parameters, or by environment variables.

Let’s assume your Postgresql server is at postgres.localdomain, the database is called sensors, the database user is geordi and the password is laForge. To connect to it via command line, invoke Geordi like this:

java -jar geordi.jar \
  --database jdbc:postgresql://postgres.localdomain/sensors \
  --user geordi \
  --password laForge

You can also use environment variables, so the password is not visible in the process list:

export GEORDI_DATABASE=jdbc:postgresql://postgres.localdomain/sensors
export GEORDI_USER=geordi
export GEORDI_PASSWORD=laForge
java -jar geordi.jar

To stop Geordi again, just kill the process or press ctrl-c on the command line.

systemd

To run Geordi on Linux via systemd, create a file /usr/lib/systemd/system/geordi.service with the following content (adapt the ExecStart paths to your installation):

[Unit]
Description=Geordi, the sensor poller
After=network.target

[Service]
EnvironmentFile=/etc/geordi.conf
User=nobody
ExecStart=/usr/bin/java -jar /usr/local/lib/geordi.jar
SuccessExitStatus=143
TimeoutStopSec=10
Restart=on-failure
RestartSec=5

[Install]
WantedBy=multi-user.target

Also create a file /etc/geordi.conf with the following content (adapted to your database):

GEORDI_DATABASE=jdbc:postgresql://postgres.localdomain/sensors
GEORDI_USER=geordi
GEORDI_PASSWORD=laForge

Make sure this file can only be read by the root user.

You can now start Geordi via:

systemctl start geordi

Check if Geordi is actually running:

systemctl status geordi

To make Geordi start after a reboot, use:

systemctl enable geordi