Golang streams and readers - go

Question

I am writing a simple script to get download unzip the tar.gz file and then remove it. Whenever I try to remove it I get an error:
The process cannot access the file because it is being used by another process.
I assume the error is in how I pass the file to the extractTarGz function, but I am not sure.
Here is the code:
package main
import (
"archive/tar"
"compress/gzip"
"io"
"log"
"os"
)
func main() {
f, err := os.Open("file.tar.gz")
if err != nil {
panic(err)
}
defer f.Close()
extractTarGz(f)
err = os.Remove("file.tar.gz")
}
func extractTarGz(gzipStream io.Reader) {
uncompressedStream, err := gzip.NewReader(gzipStream)
if err != nil {
log.Fatal("ExtractTarGz: NewReader failed")
}
tarReader := tar.NewReader(uncompressedStream)
for true {
header, err := tarReader.Next()
if err == io.EOF {
break
}
if err != nil {
log.Fatalf("ExtractTarGz: Next() failed: %s", err.Error())
}
switch header.Typeflag {
case tar.TypeDir:
if err := os.Mkdir(header.Name, 0755); err != nil {
log.Fatalf("ExtractTarGz: Mkdir() failed: %s", err.Error())
}
case tar.TypeReg:
outFile, err := os.Create(header.Name)
if err != nil {
log.Fatalf("ExtractTarGz: Create() failed: %s", err.Error())
}
defer outFile.Close()
if _, err := io.Copy(outFile, tarReader); err != nil {
log.Fatalf("ExtractTarGz: Copy() failed: %s", err.Error())
}
default:
log.Fatalf(
"ExtractTarGz: uknown type: %s in %s",
header.Typeflag,
header.Name)
}
}
}

Answer 1

You should first close the file, and then attempt to remove it. Since you close it using defer, that will / would be called after the os.Remove() call.
Try it like this:
name := "file.tar.gz"
defer func() {
if err = os.Remove(name); err != nil {
log.Printf("Failed to remove %s: %v", name, err)
}
}()
f, err := os.Open(name)
if err != nil {
panic(err)
}
defer f.Close()
extractTarGz(f)
Deferred functions are executed in LIFO (last-in-first-out) order, so first f.Close() will be called, and then the other which tries to remove the file. Quoting from Spec: Deferred statements:
...deferred functions are invoked immediately before the surrounding function returns, in the reverse order they were deferred.

Answer 2

f, err := os.Open("file.tar.gz")
if err != nil {
panic(err)
}
defer f.Close()
extractTarGz(f)
err = os.Remove("file.tar.gz")
At the very least, you need to close the file before you removeit.
err = f.Close()
if err != nil {
panic(err)
}
err = os.Remove("file.tar.gz")
defer f.Close() won't run until the end of the function.