helmver.go

package helm

import (
	"fmt"
	"io/ioutil"
	"os"
	"path"

	"gopkg.in/yaml.v2"
	"k8s.io/apimachinery/pkg/apis/meta/v1/unstructured"
)

var (
	// HelmV2 represents helm V2 specific settings
	HelmV2 = HelmVer{
		binaryName:           "helm2",
		templateNameArg:      "--name",
		kubeVersionSupported: true,
		showCommand:          "inspect",
		pullCommand:          "fetch",
		initSupported:        true,
	}
	// HelmV3 represents helm V3 specific settings
	HelmV3 = HelmVer{
		binaryName:                  "helm",
		templateNameArg:             "--name-template",
		kubeVersionSupported:        false,
		showCommand:                 "show",
		pullCommand:                 "pull",
		initSupported:               false,
		getPostTemplateCallback:     cleanupChartLockFile,
		additionalTemplateArgs:      []string{"--include-crds"},
		insecureSkipVerifySupported: true,
	}
)

// workaround for Helm3 bug. Remove after https://github.com/helm/helm/issues/6870 is fixed.
// The `helm template` command generates Chart.lock after which `helm dependency build` does not work
// As workaround removing lock file unless it exists before running helm template
func cleanupChartLockFile(chartPath string) (func(), error) {
	exists := true
	lockPath := path.Join(chartPath, "Chart.lock")
	if _, err := os.Stat(lockPath); err != nil {
		if os.IsNotExist(err) {
			exists = false
		} else {
			return nil, err
		}
	}
	return func() {
		if !exists {
			_ = os.Remove(lockPath)
		}
	}, nil
}

func getHelmVersion(chartPath string) (*HelmVer, error) {
	data, err := ioutil.ReadFile(path.Join(chartPath, "Chart.yaml"))
	if err != nil {
		return nil, err
	}
	obj := make(map[string]interface{})
	err = yaml.Unmarshal(data, &obj)
	if err != nil {
		return nil, err
	}
	version, _, _ := unstructured.NestedString(obj, "apiVersion")
	switch version {
	case "", "v1":
		return &HelmV2, nil
	case "v2":
		return &HelmV3, nil

	}
	return nil, fmt.Errorf("helm chart version '%s' is not supported", version)
}

// HelmVer contains Helm version specific settings such as helm binary and command names
type HelmVer struct {
	binaryName                  string
	initSupported               bool
	templateNameArg             string
	showCommand                 string
	pullCommand                 string
	kubeVersionSupported        bool
	getPostTemplateCallback     func(chartPath string) (func(), error)
	additionalTemplateArgs      []string
	insecureSkipVerifySupported bool
}