Utility for hashing the records of a file

hash_file.go

package main

import (
	"crypto/hmac"
	"crypto/sha256"
	"encoding/csv"
	"flag"
	"fmt"
	"log"
	"os"
	"strings"
)

func main() {
	hmacKey := flag.String("hmac-key", "", "key string for hmac")
	inputFilename := flag.String("input-file", "", "path to input csv")
	outputFilename := flag.String("output-file", "out.log", "path to output file")
	flag.Parse()

	in, err := os.Open(*inputFilename) // For read access.
	if err != nil {
		log.Fatal(err)
	}

	out, err := os.Create(*outputFilename) // for write access
	if err != nil {
		log.Fatal(err)
	}

	r := csv.NewReader(in)

	mac := hmac.New(sha256.New, []byte(*hmacKey))

	for {
		line, err := r.Read()
		if len(line) == 0 || err != nil {
			if err != nil && err.Error() != "EOF" {
				log.Printf("Error %v", err)
			}
			break
		}
		mac.Reset()
		record := strings.Trim(line[0], `"`)
		mac.Write([]byte(record))
		fmt.Fprintf(out, "%x\n", mac.Sum(nil))
	}

}