ePrivacy and GPDR Cookie Consent by TermsFeed Generator Home Automation System - Openhab persistence service with InfluxDB | OpenHAB - SmartHome | DomoticsDuino - Computer engineer, Smart Home / OpenHAB, Flight Sim and others...

OpenHAB - SmartHome

The funny Home Automation

OpenHAB - SmartHome (225 posts)

06/11/2017

Home Automation System - Openhab persistence service with InfluxDB

by Marco Lamanna




In the last few days I studied the "persistence" service in OpenHAB v.2, just to store acquired data and be ready to create dashboards.

As usual, official docs are the best choice:


I chose InfluxDB as persistence service, a time series database, easy to integrate in Grafana, a web platform for dashboards creation.

The first thing to do is to install InfluxDB on the RPI3 (the same where OpenHAB is already running) following the official documentation https://docs.influxdata.com/influxdb/v1.3/introduction/installation/

Next, I have to enable the persistence service on OpenHAB v.2, using PaperUI, Add-ons section, Persistence tab


Then, OpenHAB must be configured with the InfluxDB connection info, editing services/influxdb.cfg file in the usual OpenHAB configuration folder. In my case, I used all the default options, so I just entered the password.

This is my configuration file:

# The database URL, e.g. http://127.0.0.1:8086 or https://127.0.0.1:8084 .
# Defaults to: http://127.0.0.1:8086
# url=http(s)://<host>:<port>

# The name of the database user, e.g. openhab.
# Defaults to: openhab
# user=<user>

# The password of the database user.
password=XXXXXXX

# The name of the database, e.g. openhab.
# Defaults to: openhab
# db=<database>

On the official guide you can find all the options: http://docs.openhab.org/addons/persistence/influxdb/readme.html

Now it's time to build the persistence strategy to let OpenHAB knows how store data on InfluxDB; in a few words I have to decided, item for item, when datas will be stored on db. I can choose between many options: on every change, on every update or by time schedule, using Quartz syntax. To do so, I created a new configuration file in the /etc/openhab2/persistence folder, called influxdb.persist. In this file I defined which kind of persistence strategy I will use (Strategies section...) and assigned them to items and groups (Items section).


Official docs:

My Strategies section is as follow:

Strategies {
everyMinute: "0 * * * * ?"
everyHour: "0 0 * * * ?"
everyDay: "0 0 0 * * ?"
default = everyUpdate, restoreOnStartup
}


I used groups to assign the persistence strategies to items; so I defined new groups in /etc/items/groups.items file

GroupgPersistence(gAll)
GroupgPersistence1m(gAll)
GroupgPersistence1h(gAll)
Group gPersistence1d(gAll)
GroupgPersistenceChange(gAll)

then I'll assign them the persistence strategy just defined in the Items section of the influxdb.persist file

Items {
gPersistence*:
gPersistence1d* : strategy = everyDay, restoreOnStartup
gPersistence1h* : strategy = everyHour, restoreOnStartup
gPersistence1m* : strategy = everyMinute, restoreOnStartup
gPersistenceChange*: strategy = everyChange, restoreOnStartup
.........
}

I will easily assign these groups to items to assign a particular persistence strategy

In the next post I will speak about Grafana, a powerful tool to build dashboard.