pachyderm / yaml

YAML support for the Go language.

YAML support for the Go language

Note: This package is a fork of https://github.com/go-yaml/yaml (v3). That library was missing a few features that Pachyderm needs when handling YAML, including the ability to rely on json struct tags during marshalling and unmarshalling. We also hope to finish adding multi-document support (so that multiple JSON documents, of form { d1 }{ d2 }... can be parsed).

Issues and pull requests are welcome, though we recommend, when possible, sending issues and PRs to the original repo.

We will try to keep this repo up-to-date with the v3 branch of that repo, and we hope to migrate Pachyderm to it fully (and deprecate this repo). We will once they (or gogoproto) add features that will allow us to marshal and unmarshal generated protobuf structs to and from YAML faithfully.

---

Introduction

The yaml package enables Go programs to comfortably encode and decode YAML values. It was developed within Canonical as part of the juju project, and is based on a pure Go port of the well-known libyaml C library to parse and generate YAML data quickly and reliably.

Compatibility

The yaml package supports most of YAML 1.2, but preserves some behavior from 1.1 for backwards compatibility.

Specifically, as of v3 of the yaml package:

• YAML 1.1 bools (yes/no, on/off) are supported as long as they are being decoded into a typed bool value. Otherwise they behave as a string. Booleans in YAML 1.2 are true/false only.
• Octals encode and decode as 0777 per YAML 1.1, rather than 0o777 as specified in YAML 1.2, because most parsers still use the old format. Octals in the 0o777 format are supported though, so new files work.
• Does not support base-60 floats. These are gone from YAML 1.2, and were actually never supported by this package as it's clearly a poor choice.

and offers backwards compatibility with YAML 1.1 in some cases. 1.2, including support for anchors, tags, map merging, etc. Multi-document unmarshalling is not yet implemented, and base-60 floats from YAML 1.1 are purposefully not supported since they're a poor design and are gone in YAML 1.2.

Installation and usage

The import path for the package is gopkg.in/pachyderm/yaml.v3.

To install it, run:

go get gopkg.in/pachyderm/yaml.v3

API documentation

This repository is a fork of github.com/go-yaml/yaml. To view the documentation of the original package, visit the following link in your browser:

• https://gopkg.in/yaml.v3

API stability

The package API for yaml v3 will remain stable as described in gopkg.in.

License

The yaml package is licensed under the MIT and Apache License 2.0 licenses. Please see the LICENSE file for details.

Example

package main

import (
        "fmt"
        "log"

        "gopkg.in/pachyderm/yaml.v3"
)

var data = `
a: Easy!
b:
  c: 2
  d: [3, 4]
`

// Note: struct fields must be public in order for unmarshal to
// correctly populate the data.
type T struct {
        A string
        B struct {
                RenamedC int   `yaml:"c"`
                D        []int `yaml:",flow"`
        }
}

func main() {
        t := T{}
    
        err := yaml.Unmarshal([]byte(data), &t)
        if err != nil {
                log.Fatalf("error: %v", err)
        }
        fmt.Printf("--- t:\n%v\n\n", t)
    
        d, err := yaml.Marshal(&t)
        if err != nil {
                log.Fatalf("error: %v", err)
        }
        fmt.Printf("--- t dump:\n%s\n\n", string(d))
    
        m := make(map[interface{}]interface{})
    
        err = yaml.Unmarshal([]byte(data), &m)
        if err != nil {
                log.Fatalf("error: %v", err)
        }
        fmt.Printf("--- m:\n%v\n\n", m)
    
        d, err = yaml.Marshal(&m)
        if err != nil {
                log.Fatalf("error: %v", err)
        }
        fmt.Printf("--- m dump:\n%s\n\n", string(d))
}

This example will generate the following output:

--- t:
{Easy! {2 [3 4]}}

--- t dump:
a: Easy!
b:
  c: 2
  d: [3, 4]


--- m:
map[a:Easy! b:map[c:2 d:[3 4]]]

--- m dump:
a: Easy!
b:
  c: 2
  d:
  - 3
  - 4