Study in writing SHA1 digest of content in the gzip header

stash_sha1.go

package main

import (
        "compress/gzip"
        "crypto/rand"
        "crypto/sha1"
        "fmt"
        "io/ioutil"
        "log"
)

func main() {
        data := make([]byte, 4096)
        if _, err := rand.Reader.Read(data); err != nil {
                log.Fatal(err)
        }
        digest := sha1.Sum(data)

        fh, err := ioutil.TempFile("", "sha1_gz.")
        if err != nil {
                log.Fatal(err)
        }
        gzWrtr := gzip.NewWriter(fh)
        gzWrtr.Header.Comment = fmt.Sprintf("sha1:%x", digest)
        if _, err := gzWrtr.Write(data); err != nil {
                log.Fatal(err)
        }
        if err := gzWrtr.Close(); err != nil {
                log.Fatal(err)
        }
        if err := fh.Close(); err != nil {
                log.Fatal(err)
        }
        fmt.Println(fh.Name())
}