906f191e45
By using go-yaml directly, the properties in the document will match the order of the fields in the coresponding go type.
128 lines
3 KiB
Go
128 lines
3 KiB
Go
// Copyright 2016-2017, Pulumi Corporation. All rights reserved.
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package encoding
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import (
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"encoding/json"
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"path/filepath"
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"reflect"
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"github.com/ghodss/yaml"
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goyaml "gopkg.in/yaml.v2"
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)
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var JSONExt = ".json"
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var YAMLExt = ".yaml"
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// Exts contains a list of all the valid marshalable extension types.
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var Exts = []string{
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JSONExt,
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YAMLExt,
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// Although ".yml" is not a sanctioned YAML extension, it is used quite broadly; so we will support it.
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".yml",
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}
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// Detect auto-detects a marshaler for the given path.
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func Detect(path string) (Marshaler, string) {
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ext := filepath.Ext(path)
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if ext == "" {
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ext = DefaultExt() // default to the first (preferred) marshaler.
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}
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return Marshalers[ext], ext
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}
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// Marshalers is a map of extension to a Marshaler object for that extension.
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var Marshalers map[string]Marshaler
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// Default returns the default marshaler object.
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func Default() Marshaler {
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return Marshalers[DefaultExt()]
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}
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// DefaultExt returns the default extension to use.
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func DefaultExt() string {
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return Exts[0]
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}
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// Marshaler is a type that knows how to marshal and unmarshal data in one format.
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type Marshaler interface {
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IsJSONLike() bool
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IsYAMLLike() bool
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Marshal(v interface{}) ([]byte, error)
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Unmarshal(data []byte, v interface{}) error
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}
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var JSON Marshaler = &jsonMarshaler{}
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type jsonMarshaler struct {
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}
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func (m *jsonMarshaler) IsJSONLike() bool {
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return true
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}
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func (m *jsonMarshaler) IsYAMLLike() bool {
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return false
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}
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func (m *jsonMarshaler) Marshal(v interface{}) ([]byte, error) {
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return json.MarshalIndent(v, "", " ")
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}
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func (m *jsonMarshaler) Unmarshal(data []byte, v interface{}) error {
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// IDEA: use a "strict" marshaler, so that we can warn on unrecognized keys (avoiding silly mistakes). We should
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// set aside an officially sanctioned area in the metadata for extensibility by 3rd parties.
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return json.Unmarshal(data, v)
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}
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var YAML Marshaler = &yamlMarshaler{}
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type yamlMarshaler struct {
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}
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func (m *yamlMarshaler) IsJSONLike() bool {
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return false
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}
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func (m *yamlMarshaler) IsYAMLLike() bool {
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return true
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}
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func (m *yamlMarshaler) Marshal(v interface{}) ([]byte, error) {
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if hasYamlTags(reflect.TypeOf(v)) {
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return goyaml.Marshal(v)
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}
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return yaml.Marshal(v)
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}
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func (m *yamlMarshaler) Unmarshal(data []byte, v interface{}) error {
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// IDEA: use a "strict" marshaler, so that we can warn on unrecognized keys (avoiding silly mistakes). We should
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// set aside an officially sanctioned area in the metadata for extensibility by 3rd parties.
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if hasYamlTags(reflect.TypeOf(v)) {
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return goyaml.Unmarshal(data, v)
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}
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return yaml.Unmarshal(data, v)
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}
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// hasYamlTags checks to see if all fields of a struct have yaml tags (and hence it would be safe) to use go-yaml directly.
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func hasYamlTags(t reflect.Type) bool {
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if t.Kind() == reflect.Ptr {
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return hasYamlTags(t.Elem())
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}
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if t.Kind() != reflect.Struct {
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return false
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}
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allOk := true
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for i := 0; i < t.NumField(); i++ {
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_, has := t.Field(i).Tag.Lookup("yaml")
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allOk = allOk && has
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}
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return allOk
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}
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