grafana-metadata-api

About

The Simple JSON Datasource plugin is a backend datasource that sends generic HTTP requests to a given URL.

The goal is to map Grafana template variable values to display text using the Simple JSON Datasource plugin.

This is the server-side component of the Grafana Metadata API, serving as a hackable datasource implementation.

Being in its infancy, it just delivers static JSON files after applying some basic routing.

See also Map Grafana template variable identifiers to text labels using HTTP requests.

Setup

See also Setup grafana-metadata-api.

Backend

Prerequisities

apt install nginx-extras lua-cjson git

Source code

git clone https://github.com/daq-tools/grafana-metadata-api /opt/grafana-metadata-api

Nginx server section

lua_shared_dict metadata_routes 1M;

Nginx virtual host section

server {

    # ...

    # Configure Grafana Metadata API
    include /opt/grafana-metadata-api/src/grafana-metadata-api.conf;

}

General usage

Add file

Just drop some .json files into /var/lib/grafana-metadata-api:

$ cat /var/lib/grafana-metadata-api/luftdaten-stations-grafana.json
[
    {"value": 8119, "text": "Karlsbader Stra\u00dfe, B\u00fcchenbach, Bayern, DE"},
    {"value": 1234, "text": "Hauptstra\u00dfe, Wolfratshausen, Bayern, DE"}
]

Grafana will use the text property as a the template variable's label, and the value property as the raw value of the template variable.

HTTP API

The files dropped into /var/lib/grafana-metadata-api will be offered through a HTTP API:

# GET request with filename in URI
http https://weather.hiveeyes.org/metadata/luftdaten-stations-grafana.json

# POST with filename as target
echo '{"target": "luftdaten-stations-grafana.json"}' | http POST https://weather.hiveeyes.org/metadata/search

# POST with query expression as target (using custom routes)
echo '{"target": "SELECT * FROM luftdaten_stations"}' | http POST https://weather.hiveeyes.org/metadata/search

Usage from Grafana

Grafana plugin

Please install the plugin Simple JSON Datasource - a generic backend datasource into your Grafana instance:

grafana-cli plugins install grafana-simple-json-datasource
systemctl restart grafana-server

Grafana datasource

Add a new data source to your Grafana instance:

Name:   environmental-metadata
Type:   SimpleJson
URL:    https://weather.hiveeyes.org/metadata
Access: proxy

See also https://community.hiveeyes.org/t/1189/3.

Grafana variable

Add a new data source to your Grafana dashboard:

Name:           location_id
Label:          Location
Type:           Query

Data source:    environmental-metadata
Refresh:        On Dashboard Load
Query:          luftdaten-stations-grafana.json
Sort:           Alphabetical (asc)

Multi-value:    yes

See also https://community.hiveeyes.org/t/1189/4.