Signal K Node server plugin to write Signal K data to InfluxDB
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Latest commit 6fb21d9 Jan 5, 2019

README.md

Signal K to InfluxDb Plugin

Signal K Node server plugin to write all simple numeric Signal K values to InfluxDB, a time series database.

Once the data is in InfluxDb you can use for example Grafana to draw pretty graphs of your data.

The plugin assumes that the database you specify exists. You can create one with

curl -X POST http://localhost:8086/query?q=CREATE+DATABASE+boatdata

The plugin writes only self data. It converts Signal K paths to InfluxDb measurement keys in CamelCase format, eg. navigationPosition.

Adding support for non-self data would be pretty easy by adding context as InfluxDB tags.

Position handling and tracks

If enabled by black/whitelist configuration navigation.position updates are written to the db no more frequently than once per second. More frequent updates are simply ignored.

The coordinates are written as [lon, lat] strings for minimal postprocessing in GeoJSON conversion.

The plugin creates /signalk/vX/api/self/track endpoint that accepts two parameters:

  • timespan in the xxxY format, where xxx is a Number and Y one of
    • s (seconds)
    • m (minutes)
    • h (hours)
    • d (days)
    • w (weeks)
  • resolution in the same format and returns GeoJSON MultiLineString. For example http://localhost:3000/signalk/v1/api/self/track?timespan=1d&resolution=1h will return the data for the last 1 day (24 hours) with one position per hour. The data is simply sampled with InfluxDB's first() function.

Provider

If you want to import log files to InfluxDb this plugin provides also a provider interface that you can include in your input pipeline. First configure your log playback, then stop the server and insert the following entry in your settings.json:

        {
          "type": "signalk-to-influxdb/provider",
          "options": {
            "host": "localhost",
            "port": 8086,
            "database": "signalk",
            "selfId": <your self id here>,
            "batchSize": 1000
          }
        }

Try it out

You can start a local InfluxDb & Grafana with docker-compose up and then configure the plugin to write to localhost:8086 and then configure Grafana to use InfluxDb data.