resources

go-resources

Important

You should use the embed package instead of this tool. See https://pkg.go.dev/embed for more information.

Only use this tool if you need to support older (< 1.16) versions of Go.

go-resources is a tool to embed files into Go source code.

Installation

go install github.com/forensicanalysis/go-resources@latest

Usage

resources -h
Usage resources:
  -output filename
        filename to write the output to
  -package name
        name of the package to generate (default "main")
  -tag tag
        tag to use for the generated package (default no tag)
  -trim prefix
        path prefix to remove from the resulting file path in the virtual filesystem
  -var name
        name of the variable to assign the virtual filesystem to (default "FS")

Optimization

Generating resources result in a very high number of lines of code, 1MB of resources result about 5MB of code at over 87,000 lines of code. This is caused by the chosen representation of the file contents within the generated file.

Instead of a (binary) string, resources transforms each file into an actual byte slice. For example, a file with content Hello, world! will be represented as follows:

var FS = map[string][]byte{
  "/hello.txt": []byte{
      0x48, 0x65, 0x6c, 0x6c, 0x6f, 0x2c, 0x20, 0x57, 0x6f, 0x72, 0x6c, 0x64,
      0x21,
  },
}

While this seems wasteful, the compiled binary is not really affected. If you add 1MB of resources, your binary will increase 1MB as well.

However, compiling this many lines of code takes time and slows down the compiler. To avoid recompiling the resources every time and leverage the compiler cache, generate your resources into a standalone package and then import it, this will allow for faster iteration as you don't have to wait for the resources to be compiled with every change.

mkdir -p assets
resources -var=FS -package=assets -output=assets/assets.go your/files/here

package main

import "importpath/to/assets"

func main() {
  data, ok := assets.FS["your/files/here"]
  // ...
}

Credits

This is a fork of https://github.com/omeid/go-resources