Find a file by regex in Golang, given the regex and path - go

Question

I'm trying to implement cache busting, via the following:
on the front end of things, I insert, via JS plugin, content hash to the asset filenames (e.g. bundle.1947shkey7.js)
in the HTML file, use some template tag to create the asset (e.g. <script>) tags for me
from the Golang side, have template func that will extract the directory path dirpath, create a regex from the filename filenameRegex, and use dirpath,filenameRegex to find the file and form the tag for it.
Most of this is already working, except I have no idea how best to do that regex-based find.
The regex for the file is something like [name].\\w+.[ext], for reference. This works and I've tested it.
However, how to use that regex and the dirpath to get the actual file's path? I know we can do something like
filepath.Walk(dirpath, func(path string, info os.FileInfo, err error) error {
// logic to check info.IsDir(), info.Name(), and written actual filename
})
but there's one problem with this: the complexity. If I understand this correctly, this is going to execute for every file in directory dirname!
Is this the only way to find the asset filename via regex or is there a much simpler way?

Answer 1

You can use something like this, where you can customize the callback to your
needs:
package main
import (
"io/fs"
"path/filepath"
)
func glob(root string, fn func(string)bool) []string {
var files []string
filepath.WalkDir(root, func(s string, d fs.DirEntry, e error) error {
if fn(s) {
files = append(files, s)
}
return nil
})
return files
}
func main() {
files := glob(".", func(s string) bool {
return filepath.Ext(s) == ".js"
})
for _, file := range files {
println(file)
}
}