How do I pass custom kube config to helm3 go client?

[vadasambar]

Hi, is there a way to pass custom kube config to helm go client? I want to use helm 3 client to programmatically install a helm chart in a remote cluster. I want to create a kube config in my code and pass it to the client so that I can install the chart in my remote Kubernetes cluster.

I went through the code and seems like I can pass genericclioptions.RESTClientGetter to client.New

helm/pkg/kube/client.go

Line 77 in 5519308

func New(getter genericclioptions.RESTClientGetter) *Client {

But I am not sure about how I would go about creating my own genericclioptions.RESTClientGetter so that it also contains the custom kube config that I want to pass.

Thank you :D

[vadasambar]

Related: #6024

[bacongobbler]

https://godoc.org/k8s.io/cli-runtime/pkg/genericclioptions#ConfigFlags.ToRESTConfig

[bacongobbler]

clientcmd also has a canonical example for loading your own ClientConfig which implements the RESTClientGetter interface. https://godoc.org/k8s.io/client-go/tools/clientcmd

[vadasambar]

Thank you for the links :D

I went through the resource links. This might be a silly question but I could not find anything in the second link which implemented RESTClientGetter interface (I searched for ToRESTConfig, one of the functions of RESTClientGetter interface but could not find anything implementing it).

Also, I am building rest.Config in my code by reading the the data from a Kubernetes Secret resource.

[turkenh]

@vadasambar the following worked for me to install a helm chart programatically with helm3.

package main

import (
	"fmt"
	"os"

	"helm.sh/helm/v3/pkg/action"
	"helm.sh/helm/v3/pkg/chart/loader"
	"helm.sh/helm/v3/pkg/kube"
	_ "k8s.io/client-go/plugin/pkg/client/auth"
)

func main() {
	chartPath := "/tmp/my-chart-0.1.0.tgz"
	chart, err := loader.Load(chartPath)
	if err != nil {
		panic(err)
	}

	kubeconfigPath := "/tmp/my-kubeconfig"
	releaseName := "my-release"
	releaseNamespace := "default"
	actionConfig := new(action.Configuration)
	if err := actionConfig.Init(kube.GetConfig(kubeconfigPath, "", releaseNamespace), releaseNamespace, os.Getenv("HELM_DRIVER"), func(format string, v ...interface{}) {
		fmt.Sprintf(format, v)
	}); err != nil {
		panic(err)
	}

	iCli := action.NewInstall(actionConfig)
	iCli.Namespace = releaseNamespace
	iCli.ReleaseName = releaseName
	rel, err := iCli.Run(chart, nil)
	if err != nil {
		panic(err)
	}
	fmt.Println("Successfully installed release: ", rel.Name)
}

[vadasambar]

Hey @turkenh ! Sorry for the late reply. Thank you for the example :D

[hickeyma]

@vadasambar Closing as the issue is answered and example given. Thanks for the example @turkenh

[glianyi]

mark

[triThirty]

@vadasambar hi, I am searching for the RESTClientGetter object. Could you please teel me how to get an object which implements RESTClientGetter interface? Thank you so much.

[bahlo]

How would I initialize an action.Configuration with a kubconfig in memory as []byte? Do I really have to write it to disk, just to read it again?

[liuming-dev]

How would I initialize an action.Configuration with a kubconfig in memory as []byte? Do I really have to write it to disk, just to read it again?

e.g.

	restClientGetter := helmapi.NewRESTClientGetter(namespace, kubeConfig)

	configuration := new(action.Configuration)
	if err := configuration.Init(restClientGetter, namespace, os.Getenv("HELM_DRIVER"), util.FakeDebugLog); err != nil {
		return nil, err
	}

func NewRESTClientGetter(namespace, kubeConfig string) *SimpleRESTClientGetter {
	return &SimpleRESTClientGetter{
		Namespace:  namespace,
		KubeConfig: kubeConfig,
	}
}

SimpleRESTClientGetter is an implementation of RESTClientGetter
KubeConfig is the string content of a KubeConfig

[bahlo]

@liuming-tech I'm sorry, but what pkg is helmapi? I can't find a SimpleRESTClientGetter anywhere.

[liuming-dev]

@liuming-tech I'm sorry, but what pkg is helmapi? I can't find a SimpleRESTClientGetter anywhere.

Oh sorry, helmapi is pkg of private module, SimpleRESTClientGetter implements RESTClientGetter

func (c *SimpleRESTClientGetter) ToRESTConfig() (*rest.Config, error) {
	config, err := clientcmd.RESTConfigFromKubeConfig([]byte(c.KubeConfig))
	if err != nil {
		return nil, err
	}
	return config, nil
}

[hickeyma]

@bahlo Have a look at: https://helm.sh/docs/topics/advanced/#simple-example

[bahlo]

@hickeyma That's getting the kubeconfig path via env var, I want to pass in the kubeconfig itself.

[bahlo]

@liuming-tech Thanks, do you have the other three methods available as well? Otherwise I'll try to implement them myself.

[liuming-dev]

@liuming-tech Thanks, do you have the other three methods available as well? Otherwise I'll try to implement them myself.

import (
	"k8s.io/apimachinery/pkg/api/meta"
	"k8s.io/client-go/discovery"
	"k8s.io/client-go/discovery/cached/memory"
	"k8s.io/client-go/rest"
	"k8s.io/client-go/restmapper"
	"k8s.io/client-go/tools/clientcmd"
)

type SimpleRESTClientGetter struct {
	Namespace  string
	KubeConfig string
}

func NewRESTClientGetter(namespace, kubeConfig string) *SimpleRESTClientGetter {
	return &SimpleRESTClientGetter{
		Namespace:  namespace,
		KubeConfig: kubeConfig,
	}
}

func (c *SimpleRESTClientGetter) ToRESTConfig() (*rest.Config, error) {
	config, err := clientcmd.RESTConfigFromKubeConfig([]byte(c.KubeConfig))
	if err != nil {
		return nil, err
	}
	return config, nil
}

func (c *SimpleRESTClientGetter) ToDiscoveryClient() (discovery.CachedDiscoveryInterface, error) {
	config, err := c.ToRESTConfig()
	if err != nil {
		return nil, err
	}

	// The more groups you have, the more discovery requests you need to make.
	// given 25 groups (our groups + a few custom conf) with one-ish version each, discovery needs to make 50 requests
	// double it just so we don't end up here again for a while.  This config is only used for discovery.
	config.Burst = 100

	discoveryClient, _ := discovery.NewDiscoveryClientForConfig(config)
	return memory.NewMemCacheClient(discoveryClient), nil
}

func (c *SimpleRESTClientGetter) ToRESTMapper() (meta.RESTMapper, error) {
	discoveryClient, err := c.ToDiscoveryClient()
	if err != nil {
		return nil, err
	}

	mapper := restmapper.NewDeferredDiscoveryRESTMapper(discoveryClient)
	expander := restmapper.NewShortcutExpander(mapper, discoveryClient)
	return expander, nil
}

func (c *SimpleRESTClientGetter) ToRawKubeConfigLoader() clientcmd.ClientConfig {
	loadingRules := clientcmd.NewDefaultClientConfigLoadingRules()
	// use the standard defaults for this client command
	// DEPRECATED: remove and replace with something more accurate
	loadingRules.DefaultClientConfig = &clientcmd.DefaultClientConfig

	overrides := &clientcmd.ConfigOverrides{ClusterDefaults: clientcmd.ClusterDefaults}
	overrides.Context.Namespace = c.Namespace

	return clientcmd.NewNonInteractiveDeferredLoadingClientConfig(loadingRules, overrides)
}

If there are any improvement, tell me.

[bahlo]

@liuming-tech Thanks a lot, that helps!

I think in general a kube.Load(kubeconfig []byte) method would be useful in this pkg.