helm/pkg/action/show.go

/*
Copyright The Helm Authors.

Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at

    http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.
*/

package action

import (
	"fmt"
	"strings"

	"github.com/ghodss/yaml"

	"helm.sh/helm/pkg/chart"
	"helm.sh/helm/pkg/chart/loader"
)

type ShowOutputFormat string

const (
	ShowAll    ShowOutputFormat = "all"
	ShowChart  ShowOutputFormat = "chart"
	ShowValues ShowOutputFormat = "values"
	ShowReadme ShowOutputFormat = "readme"
)

var readmeFileNames = []string{"readme.md", "readme.txt", "readme"}

func (o ShowOutputFormat) String() string {
	return string(o)
}

// Show is the action for checking a given release's information.
//
// It provides the implementation of 'helm show' and its respective subcommands.
type Show struct {
	OutputFormat ShowOutputFormat
	ChartPathOptions
}

// NewShow creates a new Show object with the given configuration.
func NewShow(output ShowOutputFormat) *Show {
	return &Show{
		OutputFormat: output,
	}
}

// Run executes 'helm show' against the given release.
func (s *Show) Run(chartpath string) (string, error) {
	var out strings.Builder
	chrt, err := loader.Load(chartpath)
	if err != nil {
		return "", err
	}
	cf, err := yaml.Marshal(chrt.Metadata)
	if err != nil {
		return "", err
	}

	if s.OutputFormat == ShowChart || s.OutputFormat == ShowAll {
		fmt.Fprintf(&out, "%s\n", cf)
	}

	if (s.OutputFormat == ShowValues || s.OutputFormat == ShowAll) && chrt.Values != nil {
		if s.OutputFormat == ShowAll {
			fmt.Fprintln(&out, "---")
		}
		b, err := yaml.Marshal(chrt.Values)
		if err != nil {
			return "", err
		}
		fmt.Fprintf(&out, "%s\n", b)
	}

	if s.OutputFormat == ShowReadme || s.OutputFormat == ShowAll {
		if s.OutputFormat == ShowAll {
			fmt.Fprintln(&out, "---")
		}
		readme := findReadme(chrt.Files)
		if readme == nil {
			return out.String(), nil
		}
		fmt.Fprintf(&out, "%s\n", readme.Data)
	}
	return out.String(), nil
}

func findReadme(files []*chart.File) (file *chart.File) {
	for _, file := range files {
		for _, n := range readmeFileNames {
			if strings.EqualFold(file.Name, n) {
				return file
			}
		}
	}
	return nil
}