A NodeRED node which allows exporting Prometheus metrics from within flows.
npm install node-red-contrib-prometheus-exporterUsing this node for NodeRED, you can define your own Prometheus metrics which will become available over an HTTP endpoint. The endpoint can be polled from a Prometheus agent or Telegraf.
Supported metric types:
* Counter
* Gauge
Labels are supported for both metric types.
The preferred way of installing the node is to use the Palette Manager in NodeRED. Just seek for node-red-contrib-prometheus-exporter and follow the instructions.
Alternatively, you can also manually install the node permanently into your embedded NodeRED application with npm:
``bash`
npm install node-red-contrib-prometheus-exporter
From the Palette Manager, pull the node "prometheus out" in the __network__ section into your flow.
In the editor of the metric node, create a new metric by clicking the pencil button next to the "Metric" drop down box. The config node editor will fire up.
In the config node editor, define the metric as you like. Name, help, and metric type are mandatory. Label names are optional. To learn more about Prometheus metrics, please refer to the Prometheus documentation.
After you have defined the metric, you can now feed the metric with values to actually populate the metrics output.
The node expects a message.payload as input with the following structure:
`json`
{
"op": "inc",
"val": 5,
"labels": {
"tag_1": "computer_123"
}
}
Choose the op property from one of the following values:
* For metrics of type __Counter__:
* inc - Increases the counter by val (without specifying val, defaults to 1)set
* For metrics of type __Gauge__:
* - Sets the gauge to val (which is mandatory for this operation)inc
* - Increases the gauge by val (without specifying val, defaults to 1)dec
* - Decreases the gauge by val (without specifying val, defaults to 1)
As described above, the val property is mandatory or optional depending on the selected op and the metric type.
Labels are always optional. Make sure, you only use label keys, which you have defined in the configuration of the node as "Labels".
Deploy the flow, open up the browser and access the /metrics endpoint of your NodeRED server.
The output should look like this:
`HELP example_counter This is an example Counter
TYPE example_counter counter
example_counter 10
$3
You can manually change the path under which the metrics are exposed. Just set the environment variable
to a path of your choice.$3
You can easily collect and expose a useful set of pre-defined metrics about the node.js process hosting the NodeRED environment. These metrics are disabled by default, but you can activate them by setting the environment variable
PROMETHEUS_COLLECT_DEFAULT_METRICS to true`.This library is licensed under Apache 2.0.
NodeRED is an awsome and carefully-written low-code environment for node.js. This library has been written and tested against NodeRED v1.2.
Under the hood, this library is built on top of the prom-client, a mature Prometheus client for node.js.
This project is sponsored by docoyo.