dashf

README

DashF

Unmarshall A file, STDIN or a URL into a golang struct. The supported formats are JSON and YAML.

What is DashF?

DashF means the flag -f. When a CLI wishes to accept a resource (filename/directory/url) they typically use the -f flag. DashF provides your cli a consistent way to unmarshall user-defined resources into golang structs. Most CLI tools process the -f flag in the same manner, but the code is typically buried and not easily re-usable.

Doesn't Viper/envconfig/pflag do this?

No. Viper and envconfig provide a great libraries for configuring your application. Viper and pflag can accept the input but provide no mechanism for processing the resource.

Example

Here is some example input JSON. This can be located in a local file, a URL or even piped via STDIN.

{
  "one": 1,
  "two": "two",
  "three": [
    {
      "a": "a",
      "b": "b",
      "c": "c"
    }
  ]
}

Example code to handle the input.

package main

import (
        "fmt"
        "github.com/cdornsife/dashf"
        "github.com/spf13/pflag"
        "os"
)

// TestStruct represents the data in the json/yaml file
// Example files are in the tests directory
type TestStruct struct {
        One   int    `json:"one"`
        Two   string `json:"two"`
        Three []struct {
                A string `json:"a"`
                B string `json:"b"`
                C string `json:"c"`
        } `json:"three"`
}

func main() {

        var inputFile string
        var out = new(TestStruct)

        pflag.StringVarP(&inputFile, "file", "f", "", "Input for create/update: json|yaml|-")
        pflag.Parse()

        err := dashf.Unmarshal(inputFile, &out)
        if err != nil {
                fmt.Printf("%+v\n", err)
                os.Exit(1)
        }

        fmt.Printf("%+v\n", out)
}

Command line usage:

$ cd example

# Pass in a - to use STDIN
$ cat ../tests/test.json | go run main.go -f -

# Specify a local file
$ go run main.go -f ../tests/test.yaml

# Specify a URL
go run main.go --file https://raw.githubusercontent.com/cdornsife/dashf/master/tests/test.yaml

Documentation

Index

• func Unmarshal(input string, result interface{}) error

Functions

func Unmarshal

func Unmarshal(input string, result interface{}) error

Unmarshal ...