open-nomad/command/data_format.go

115 lines
2.5 KiB
Go

// Copyright (c) HashiCorp, Inc.
// SPDX-License-Identifier: MPL-2.0
package command
import (
"bytes"
"fmt"
"text/template"
"github.com/Masterminds/sprig/v3"
"github.com/hashicorp/go-msgpack/codec"
)
var (
jsonHandlePretty = &codec.JsonHandle{
HTMLCharsAsIs: true,
Indent: 4,
}
)
// DataFormatter is a transformer of the data.
type DataFormatter interface {
// TransformData should return transformed string data.
TransformData(interface{}) (string, error)
}
// DataFormat returns the data formatter specified format.
func DataFormat(format, tmpl string) (DataFormatter, error) {
switch format {
case "json":
if len(tmpl) > 0 {
return nil, fmt.Errorf("json format does not support template option.")
}
return &JSONFormat{}, nil
case "template":
return &TemplateFormat{tmpl}, nil
}
return nil, fmt.Errorf("Unsupported format is specified.")
}
type JSONFormat struct{}
// TransformData returns JSON format string data.
func (p *JSONFormat) TransformData(data interface{}) (string, error) {
var buf bytes.Buffer
err := codec.NewEncoder(&buf, jsonHandlePretty).Encode(data)
if err != nil {
return "", err
}
return buf.String(), nil
}
type TemplateFormat struct {
tmpl string
}
// TransformData returns template format string data.
func (p *TemplateFormat) TransformData(data interface{}) (string, error) {
var out bytes.Buffer
if len(p.tmpl) == 0 {
return "", fmt.Errorf("template needs to be specified in golang's text/template format.")
}
t, err := template.New("").Funcs(makeFuncMap()).Parse(p.tmpl)
if err != nil {
return "", err
}
err = t.Execute(&out, data)
if err != nil {
return "", err
}
return out.String(), nil
}
func Format(json bool, template string, data interface{}) (string, error) {
var format string
if json && len(template) > 0 {
return "", fmt.Errorf("Both json and template formatting are not allowed")
} else if json {
format = "json"
} else if len(template) > 0 {
format = "template"
} else {
return "", fmt.Errorf("no formatting option given")
}
f, err := DataFormat(format, template)
if err != nil {
return "", err
}
out, err := f.TransformData(data)
if err != nil {
return "", fmt.Errorf("Error formatting the data: %w", err)
}
return out, nil
}
func makeFuncMap() template.FuncMap {
fm := template.FuncMap{}
// Add the Sprig functions to the funcmap. These functions are decorated
// with `sprig_` to match how they are treated in consul-template
for k, v := range sprig.FuncMap() {
target := "sprig_" + k
fm[target] = v
}
return fm
}