Simple script to list Procfile entries from a tar stream

list-app-processes.go

//
// Read and parse an Procfile of a tar stream from stdin
//
// example: git archive HEAD | list-app-processes
//
//
package main

import (
	"archive/tar"
	"fmt"
	"gopkg.in/yaml.v1"
	"io"
	"io/ioutil"
	"log"
	"os"
)

type Processes map[string]string

func main() {
	tarfile := tar.NewReader(os.Stdin)
	for {
		header, err := tarfile.Next()
		if err == io.EOF {
			break
		}
		if err != nil {
			log.Fatal(err)
		}
		if header.Name == "Procfile" {
			procfile, err := ioutil.ReadAll(tarfile)
			if err != nil {
				log.Fatal(err)
			}

			processes := Processes{}
			err = yaml.Unmarshal(procfile, &processes)
			if err != nil {
				log.Fatal(err)
			}

			for process, _ := range processes {
				fmt.Println(process)
			}
		}
	}
}