Hi 👋
I have tried to learn some go but I am still very much at the beginning, like understanding how to work with variables and functions. My background is mostly in python but I am not a programmer by trade.
package main
import (
"crypto/sha256"
"fmt"
"io"
"log"
"os"
"path/filepath"
)
func write_lines_to_file(lines []string, output_file string) {
f, err2 := os.Create(output_file)
if err2 != nil {
log.Fatal(err2)
}
defer f.Close()
for _, line := range lines {
_, err := f.WriteString(line + "\n")
if err != nil {
log.Fatal(err2)
}
}
}
func get_size_and_hash(file_path string) (int, string) {
file, err := os.Open(file_path)
if err != nil {
panic(err)
}
defer file.Close()
hash := sha256.New()
if _, err := io.Copy(hash, file); err != nil {
panic(err)
}
sum := fmt.Sprintf("%x", hash.Sum(nil))
file, err2 := os.Open(file_path)
if err2 != nil {
log.Fatal(err2)
}
fi, err2 := file.Stat()
if err != nil {
log.Fatal(err2)
}
my_size := fi.Size()
return int(my_size), string(sum)
}
func get_list_of_files(target_directory string) []string {
var files []string
err := filepath.Walk(target_directory, func(path string, info os.FileInfo, err error) error {
if err != nil {
fmt.Println(err)
return nil
}
if !info.IsDir() {
files = append(files, path)
}
return nil
})
if err != nil {
log.Fatal(err)
}
return files
}
func main() {
// accept directory as user input
target_directory := os.Args[1]
my_files := get_list_of_files(target_directory)
var content []string
for _, file := range my_files {
size, hash := get_size_and_hash(file)
var str_file string = string(file)
str_size := fmt.Sprint(size)
var str_hash string = string(hash)
// structure: file, checksum, size
combined_line := str_file + "," + str_hash + "," + str_size
content = append(content, combined_line)
}
var output_file string = target_directory + "/PULP_MANIFEST"
write_lines_to_file(content, output_file)
}
I am testing this using the following command: rm -f test_input/PULP_MANIFEST && go fmt pulp_manifest.go && go build pulp_manifest.go && ./pulp_manifest test_input && cat test_input/PULP_MANIFEST on Fedora with go 1.20
Known Limitations
- My rewrite does not handle files or directories with "," yet.
Untested
- Files with binary content
- Paths on macOS or Microsoft Windows
- Paths with whitespace
- Symlinks in target_directory
- target_directory as symlink
I am looking for the following feedback:
- bugs and limitations
- a was to add tests: do you have any recommendations for talks or blog posts?
- style & best practice
- a way to use static typing?!
- anything else that you would recommend a novice.
Right now, I believe my rewrite works. Feel free to shatter my assumption. Cheers.