chartjs-plugin-datasource-prometheus

Chart.js plugin for Prometheus datasource. Like Grafana, but standalone.

Usage no npm install needed!

<script type="module">
  import chartjsPluginDatasourcePrometheus from 'https://cdn.skypack.dev/chartjs-plugin-datasource-prometheus';
</script>

README

Welcome to chartjs-plugin-datasource-prometheus 👋

NPM version jsDelivr Downloads License: MIT

A Prometheus datasource for ChartJS.

screenshot

Dependencies:

Demonstration:

https://samber.github.io/chartjs-plugin-datasource-prometheus/example/

I would be happy to add links to charts using this library. Feel free to reach me by creating an issue ;)

✨ Features

  • Loads time-series from Prometheus into Chart.js.
  • Similar to Grafana, but ported to Chart.js for public-facing web applications.
  • UMD compatible, you can use it with any module loader
  • Supports line chart only (for now!)
  • Graph auto-refresh
  • Date interval can be absolute or relative to now
  • Multiple Prometheus queries into the same chart
  • Custom backend requests (useful for multitenant apps)
  • Hooks available (styling, labeling, data presentation...)
  • Custom chart messages for errors or empty Prometheus responses
  • Break or continuous lines when gap in data
  • Line styling
  • Send queries with your own Prometheus driver

⚠️ This project is not intented to replace Grafana. For monitoring purpose or internal company graph showing, Grafana will definitely be better and more secure.

🚀 Installation

Via npm:

npm install momentjs chart.js --save

npm install chartjs-plugin-datasource-prometheus --save

Via CDN:

<script src="https://cdnjs.cloudflare.com/ajax/libs/moment.js/2.24.0/moment.min.js"></script>
<script src="https://cdn.jsdelivr.net/npm/chart.js@2.9.3/dist/Chart.min.js"></script>

<script src="https://cdn.jsdelivr.net/npm/chartjs-plugin-datasource-prometheus/dist/chartjs-plugin-datasource-prometheus.umd.min.js"></script>

💡 Note that chartjs-plugin-datasource-prometheus must be loaded after Chart.js and Moment.js.

💡 Quick start

chartjs-plugin-datasource-prometheus can be used with ES6 modules, plain JavaScript and module loaders.

<canvas id="myChart"></canvas>

Then, you need to register the plugin to enable it for all charts in the page.

Chart.plugins.register(ChartDatasourcePrometheusPlugin);

Or, you can enable the plugin only for specific charts.

var chart = new Chart(ctx, {
    plugins: [ChartDatasourcePrometheusPlugin],
    options: {
        // ...
    }
});

In the example below, we display Go duration of garbage collection, for the last 12 hours:

var myChart = new Chart(ctx, {
  type: 'line',
  plugins: [ChartDatasourcePrometheusPlugin],
  options: {
    plugins: {
      'datasource-prometheus': {
        prometheus: {
          endpoint: "https://prometheus.demo.do.prometheus.io",
          baseURL: "/api/v1",   // default value
        },
        query: 'sum by (job) (go_gc_duration_seconds)',
        timeRange: {
          type: 'relative',

          // from 12 hours ago to now
          start: -12 * 60 * 60 * 1000,
          end: 0,
        },
      },
    },
  },
});

💬 Spec

Options

Property Required Description Default
prometheus.endpoint yes Prometheus hostname
prometheus.baseURL no Prometheus metric path "/api/v1"
prometheus.headers no Headers to add to Prometheus request
prometheus.auth.username no Basic auth username
prometheus.auth.password no Basic auth password
prometheus.proxy.host no Proxy hostname
prometheus.proxy.port no Proxy port
prometheus.withCredentials no Send cookies in cross-site requests false
prometheus.timeout no Prometheus request timeout in milliseconds 10000
query yes Prometheus query: string or function (see below). Supports multiple queries, using an array.
timeRange.type no Time range type: absolute or relative "absolute"
timeRange.start yes Time range start: Date object (absolute) or integer (relative)
timeRange.end yes Time range end: Date object (absolute) or integer (relative)
timeRange.step no Time between 2 data points [computed]
timeRange.minStep no Min time between 2 data points null
timeRange.msUpdateInterval no Update interval in millisecond null
fillGaps no Insert NaN values when values are missing in time range false
tension no Bezier curve tension of the line. Set to 0 to draw straightlines. This option is ignored if monotone cubic interpolation is used 0.4
cubicInterpolationMode no "default" or "monotone" "default"
stepped no false, true, "before", "middle" or "after" false
fill no Fills the area under the line false
borderWidth no Should I explain this field? 3
backgroundColor no Should I explain this field? See library source code
borderColor no Should I explain this field? See library source code
errorMsg.message no Overrides error messages null
errorMsg.font no Font of error messages "16px normal 'Helvetica Nueue'"
noDataMsg.message no Empty chart message "No data to display"
noDataMsg.font no Font of empty chart message "16px normal 'Helvetica Nueue'"

Hooks

Some hooks have been inserted into the library. It may help you to rewrite label names dynamically, set colors...

// 💡 For better serie labels, we are looking for a templating solution => please contribute ;)

Property Required Description Prototype
findInLabelMap no Custom serie label (serie: Metric) => string
findInBorderColorMap no Custom serie line color (serie: Metric) => string
findInBackgroundColorMap no Custom serie background color (serie: Metric) => string
dataSetHook no Modify data on the fly, right before display (datasets: ChartDataSet[]) => ChartDataSet[]

Examples

Multiple queries in one chart

The query field can be an array of queries. Returned series are aggregated in a single chart.

In case you want to show those queries on different axes, you can define a custom options.scales.yAxes field.

var myChart = new Chart(ctx, {
    type: 'line',
    plugins: [ChartDatasourcePrometheusPlugin],
    options: {
        scales: {
            yAxes: [
                {position: 'left'},
                {position: 'left'},
                {position: 'right'},
            ]
        },
        plugins: {
            'datasource-prometheus': {
                prometheus: {
                    endpoint: "https://prometheus.demo.do.prometheus.io",
                },
                query: ['node_load1', 'node_load5', 'node_load15'],
                timeRange: {
                    type: 'relative',

                    // from 12 hours ago to now
                    start: -12 * 60 * 60 * 1000,
                    end: 0,
                },
            },
        },
    },
});

screenshot

Auto refresh

Animations should be disabled when chart refresh itself.

var myChart = new Chart(ctx, {
    type: 'line',
    plugins: [ChartDatasourcePrometheusPlugin],
    options: {
        animation: {
            duration: 0,
        },
        plugins: {
            'datasource-prometheus': {
                prometheus: {
                    endpoint: "https://prometheus.demo.do.prometheus.io",
                },
                query: 'node_load1',
                timeRange: {
                    type: 'relative',

                    // from 10 minutes ago to now
                    start: -1 * 10 * 60 * 1000,
                    end: 0,
                    msUpdateInterval: 5000,
                },
            },
        },
    },
});

Custom queries

In the context of a multitenant application, it is not a good idea to write a query on the browser side. In that scenario, you may need to send a custom request to your backend, which is responsible for doing the final Prometheus query.

In that case, the prometheus field can be ommited. Just pass a function with the following prototype: (start: Date, end: Date, step: number) => Promise<any>.

It can be combined with traditional string queries: query: ['node_load1', customReq].

// Here, we call a fictive API that gonna query Prometheus to get the list
// of comments, wrote by the current user during the past hour.
// This endpoint will return a Prometheus-like response.
function customReq(start, end, step) {
    const startTimestamp = start.getTime() / 1000;
    const endTimestamp = end.getTime() / 1000;

    const url = `https://api.example.com/user/activity?event_type=comment.write&range_start=${startTimestamp}&end=${endTimestamp}&range_step=${step}`;
    const headers = {'Authorization': 'Bearer Ainae1Ahchiew6UhseeCh7el'};

    return fetch(url, { headers })
        .then(response => response.json())
        .then(response => response['data']);
}

const myChart = new Chart(ctx, {
    type: 'line',
    plugins: [ChartDatasourcePrometheusPlugin],
    options: {
        plugins: {
            'datasource-prometheus': {
                query: customReq,
                timeRange: {
                    type: 'relative',
                    start: -1 * 60 * 60 * 1000, // 1h ago
                    end: 0,   // now
                },
            },
        },
    },
});

🤯 Troubleshooting

CORS

Start your Prometheus instance with --web.cors.origin="www.example.com" flag or even --web.cors.origin=".*" if you like living dangerously. 😅

🔐 Security advisory

Please read the security advisory of prometheus-query library.

In the context of a multitenant application, it is not a good idea to write a query on the browser side. In that scenario, you may need to use the "custom request" feature.

🤝 Contributing

The Prometheus Datasource is open source and contributions from community (you!) are welcome.

There are many ways to contribute: writing code, documentation, reporting issues...

How-to

Author

👤 Samuel Berthe

👤 Frantisek Svoboda

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📝 License

Copyright © 2020 Samuel Berthe.

This project is MIT licensed.