mongodb

The mongodb plugin is meant to report a local MongoDB server's activity from mongostat.

It is not enabled in the published plugin set. The registry in plugins/plugins/index.ts has it commented out, so adding mongodb to the plugins array does nothing. This page documents what the code does today.

Enable it

You can't, without code changes. The source is an older class-based plugin that extends MonitoringPlugin, and plugins/lib/MonitoringPlugin.ts no longer exports that class. Every registered plugin uses the createMonitoringPlugin factory instead.

The example config has this section:

{
  "mongodb": {
    "refreshInterval": 30000,
    "uri": "mongodb://localhost:27017",
    "databases": []
  }
}

The plugin reads none of these options.

Option	Read by the code?
refreshInterval	No. mongostat runs with a fixed 10 second interval.
uri	No. The address mongodb://localhost:27017 is hard-coded.
databases	No.

What it would report

The plugin starts mongostat --json mongodb://localhost:27017 10 and keeps it running. For each line of output, it takes the localhost:27017 entry and sends it unchanged, with unique id mongodb-localhost:27017. The payload is whatever mongostat prints, such as conn, net_in, net_out, insert, query, update, delete, res and vsize.

When it alerts

The server's mongodb case raises an error when status is not "connected". The reason is MongoDB connection failed. mongostat output has no status field, so every report would be judged an error.

A new problem does not notify on the first bad report. The server holds it until a second consecutive report is still bad.

On the dashboard

The card is labelled MongoDB.

Reading	Source	Warn	Crit
CONNS	conn	none	none
NET IN	net_in, formatted as bytes	none	none
NET OUT	net_out, formatted as bytes	none	none

The card's color follows the stored status only.

Requirements

• The mongostat binary from MongoDB Database Tools on the PATH.
• A MongoDB server on localhost:27017 that accepts connections without credentials.

Gotchas

• The plugin parses each chunk of mongostat output as one JSON document. A chunk that holds two lines, or half of one, will throw.