3.2. Grafana connector

3.2.1. Introduction

Official QuasarDB Grafana plugin. It enables seamless integration between QuasarDB and the Grafana analytics and monitoring platform . You can view the source code and download the connector from the official GitHub repository .

3.2.2. Prerequisites

This documentation assumes you have:

• Grafana installed and running .

• Both the QuasarDB daemon qdbd and the REST API qdb_rest running.

3.2.3. Installation

The easiest way to install the plugin is via the Grafana CLI

 $ grafana-cli --pluginUrl https://download.quasar.ai/quasardb/3.14/3.14.3/api/grafana/qdb-grafana-plugin.zip plugins install qdb-grafana-datasource

Alternatively, you can clone the git repository to your Grafana plugins directory (this is usually /var/lib/grafana/plugins on Linux-based systems)

$ cd /var/lib/grafana/plugins
$ git clone https://github.com/bureau14/qdb-grafana-plugin.git

Finally, restart your Grafana server and the plugin will be added automatically.

3.2.4. Configuration

Navigate your web browser to Grafana’s datasource configuration, and click Add data source. You will see quasardb-datasource as one of the available data sources.

If your cluster is not secured you just need to fill in the REST API URL (default is http://localhost:40080) into the URL field as shown below:

If your cluster is secured make sure to use the secure REST API URL (default is https://localhost:40493) when filling in the URL field.

Fill in the User name and User key fields using the information found in your user private key file as shown below:

After you are done, click Save & Test and you are ready to start creating visualizations using QuasarDB.

3.2.5. Usage

3.2.5.1. Querying

You can add a visualization using QuasarDB by selecting the QuasarDB Data Source when creating a new visualization.

In addition to normal query syntax you can use the $__range and $__interval variables provided by Grafana.

For example the query:

SELECT * FROM measurements IN RANGE(2007, 2008) GROUP BY 1h

Could be written to use Grafana’s variables like this:

SELECT * FROM measurements IN $__range GROUP BY $__interval

For more information on query syntax see our query language reference.

3.2.5.2. Query variables

Query variables enable you to create more interactive and dynamic dashboards by writing a data source query that can return a list of tables, column values, or tag values. Query variables support numeric and string values.

For more information on how to use Grafana variables check the official documentation .

3.2.5.2.1. Adding query variables

1. In your dashboard view go to dashboard settings -> variables and click on add new variable.

   

2. In query options, select your QuasarDB data source.

3. Enter a query in the Query text box.

4. Run the query to verify the results, then apply the changes.

   

Note

Query variables are formatted as column_name=column_value. This makes them easier to reuse in queries. If no column_name is provided (e.g., when listing tables) query variables are formatted as column_value only.

3.2.5.2.2. Creating query variables using simplified query syntax

For simpler queries where you want to select distinct values from a column, you can use simplified query syntax. This reduces the likelihood of errors in queries and speeds up creating simple variables.

For more complex queries you can use your own queries.

Example usage of simplified query syntax in Grafana:

Query:

SELECT column FROM table GROUP BY column

can be written as:

table.column

Note

Table names containing . or / characters should be placed inside double quotes.

Note

By default, if the Include all option checkbox is checked, the All variable is set to 1=1.

3.2.5.2.3. Querying using query variables

Single value variables are replaced with their values.

For example:

Grafana query:

SELECT * FROM measurements WHERE $sensor_id

will be translated to:

SELECT * FROM measurements WHERE sensor_id='sensor1'

You can also use multiple values of a variable in a query by selecting the Multi value checkbox when creating it. By default, all values are joined with OR. You can change this behaviour by including the variable inside one of the special variables listed below:

• $__or - splits variables with OR

• $__and - splits variables with AND

• $__comma - splits variables with ,

Examples:

Grafana query:

SELECT * FROM measurements WHERE ${sensor_id}

will be translated to:

SELECT * FROM measurements WHERE (sensor_id='sensor3' OR sensor_id='sensor2')

Grafana query:

SELECT * FROM measurements WHERE $__or($sensor_type)

will be translated to:

SELECT * FROM measurements WHERE (sensor_type='temperature' OR sensor_type='vibration')

Grafana query:

SELECT * FROM $__comma($tables) WHERE $__or($sensor_id)

will be translated to:

SELECT * FROM foo_03, measurements WHERE (sensor_id='sensor2' OR sensor_id='sensor3')