k-charted

K-Charted

Dashboards and Charts library for Kubernetes, to use with MonitoringDashboard custom resources as documented in Kiali.

K-Charted is used in Kiali to fetch Prometheus metrics and display them in a dashboard

It consists in a Go library and a TypeScript / React library. The Go code:

• Provides a service that loads dashboards from custom Kubernetes resources and fill them up with timeseries data fetched from Prometheus.
• Includes some helpers to use as an HTTP endpoint handler

The TypeScript code:

• Provides Dashboards, with one available implementation using React and Patternfly 4 (ie. Victory charts). The code structure should make it easy to provide other implementations (we had Patternfly 3 as well, in the past).
• Of course, the data model used for these components is exactly what is returned from Go. So no extra manipulation is required.

Usage

Full-minimal working example: https://github.com/jotak/k-charted-server

Go

This code must run in-cluster.

Using the provided HTTP handler:

import (
  kconf "github.com/kiali/k-charted/config"
	kxconf "github.com/kiali/k-charted/config/extconfig"
	klog "github.com/kiali/k-charted/log"
  khttp "github.com/kiali/k-charted/http"
  // ...
)

var cfg = kconf.Config{
  GlobalNamespace:  "default",
  NamespaceLabel: "namespace",
  Prometheus: kxconf.PrometheusConfig{
    URL: "http://prometheus",
  },
}
var logger = klog.LogAdapter{
  Errorf: log.Errorf,
  Tracef: log.Tracef,
}

func getDashboard(w http.ResponseWriter, r *http.Request) {
	khttp.DashboardHandler(r.URL.Query(), mux.Vars(r), w, cfg, logger)
}

func SetRoute() {
  r := mux.NewRouter()
  r.HandleFunc("/api/namespaces/{namespace}/dashboards/{dashboard}", getDashboard)
}

Or alternatively, calling the dashboards service instead:

import (
	kbus "github.com/kiali/k-charted/business"
	kconf "github.com/kiali/k-charted/config"
	kxconf "github.com/kiali/k-charted/config/extconfig"
	klog "github.com/kiali/k-charted/log"
)

var cfg = kconf.Config{
  GlobalNamespace:  "default",
  NamespaceLabel: "namespace",
  Prometheus: kxconf.PrometheusConfig{
    URL: "http://prometheus",
  },
}
var logger = klog.LogAdapter{
  Errorf: log.Errorf,
  Tracef: log.Tracef,
}

// ...

  dashboardsService := kbus.NewDashboardsService(cfg, logger)
  dashboard, err := dashboardsService.GetDashboard(model.DashboardQuery{Namespace: "my-namespace"}, "my-dashboard-name")

Config

• GlobalNamespace: namespace that holds default dashboards. When a dashboard is looked for in a given namespace, when not found and if GlobalNamespace is defined, it will be searched then in that GlobalNamespace. Undefined by default.

• NamespaceLabel: the name of the Prometheus label that holds namespace. namespace by default.

• Prometheus: Prometheus configuration.

  • URL: URL of the Prometheus server, accessible from server-side.
  • Auth: Authentication options, if any (see https://github.com/kiali/k-charted/blob/master/config/extconfig/extconfig.go).

• Grafana: Grafana configuration. This is optional, only needed if external links to Grafana dashboards have been defined within the MonitoringDashboards custom resources in use.

  • URL: URL of the Grafana server, accessible from client-side / browser.
  • InClusterURL: URL of the Grafana server, accessible from server-side.
  • Auth: Authentication options, if any (see https://github.com/kiali/k-charted/blob/master/config/extconfig/extconfig.go).

• PodsLoader: optional pods supplier function, it enables reading dashboard names from pods annotations.

LogAdapter

It binds any logging function to be used in K-Charted. It can be omitted, in which case nothing will be logged.

• Errorf
• Warningf
• Infof
• Tracef

React (Javascript / TypeScript)

Import @kiali/k-charted-pf4. Example with axios:

  axios.get(`/namespaces/${this.state.namespace}/dashboards/${this.state.dashboardName}`).then(rs => {
    this.setState({ dashboard: rs.data });
  });

  render() {
    if (this.state.dashboard) {
      return (<Dashboard dashboard={this.state.dashboard} />)
    }
    return (<>Empty</>);
  }

Check out MetricsOption.ts file to see how the dashboard can be tuned (filtering by labels, aggregations, etc.)

First build preparation

Install golangci-lint, example with v1.16.0:

curl -sfL https://install.goreleaser.com/github.com/golangci/golangci-lint.sh | sh -s -- -b $(go env GOPATH)/bin v1.16.0

Build

To build/lint/test the backend, run:

make go

For the frontend, run:

make pf4

Development setup (e.g. with Kiali)

One solution to easily work and test with Kiali is to use go mod replace directive, and npm linking.

Assuming the repos are located within your $GOPATH (but that's not mandatory, just adapt the instructions below), run:

cd ${GOPATH}/src/github.com/kiali/kiali
go mod edit -replace github.com/kiali/k-charted=../k-charted

Similarly, you can use yarn link for the web UI side. Assuming your kiali-ui is in /work/kiali-ui:

cd ${GOPATH}/src/github.com/kiali/k-charted/web/pf4
yarn link

cd /work/kiali-ui
yarn link @kiali/k-charted-pf4

After testing, you should remove the link:

cd ${GOPATH}/src/github.com/kiali/kiali
go mod edit -dropreplace github.com/kiali/k-charted

cd /work/kiali-ui
yarn unlink @kiali/k-charted-pf4

Contribute

You're welcome!

If you want to chat, come to the #kiali channel on IRC/Freenode.