gofgen

What is this about

gofgen transforms a directory into a usable Go package that exposes the files under that directory to your program at runtime.

Motivation

Suppose that in your Go project, you have a directory called res (it could have any name), containing static files:

project/
├── main.go
└── res/
    ├── html/
    |   └── index.html
    └── css/
        ├── main.css
        └── utils.css

Before compiling your program, you cd into res and run gofgen. gofgen, then, generates a file named init_gofgen.go. This file contains Go code loading everything under res into memory at compile time.

project/
├── main.go
└── res/
    ├── html/
    |   └── index.html
    ├── css/
    |   ├── main.css
    |   └── utils.css
    └── init_gofgen.go

Finally, you can access all the files under res from your code. For example, main.go might look like this:

package main

import (
	"fmt"
	"<yourpackage>/res"
)

func main() {
	b, ok := res.FS.Get("/html/index.html")
	fmt.Println(string(b))
	fmt.Println(ok)
}

As the example shows, you can access the in-memory file system, loaded by gofgen's init file, using the FS variable now available from your res package. Every file inside res must be referred from the root directory, that is, starting with an /, as in /html/index.html.

Your directory res was once just a local storage for your static files - now it's an accessible Go package!

Examples

using all options

$ gofgen --package-name main --input-dir /movies/taxi-driver/screenshots --output-file /opt/some-amazing-go-project/init_screenshots.go

This will generate /opt/some-amazing-go-project/init.go, having package main, containing Go code that exposes the files under /movies/taxi-driver/screenshots.

using zero options

$ cd ~/my-amazing-project/resources && gofgen

This will generate ~/my-amazing-project/resources/init_gofgen.go, having package resources, exposing files under ~/my-amazing-project/resources.

How to install

Using go get:

go install github.com/xrash/gofgen/cmd/gofgen@latest

Manually compiling:

$ git clone https://github.com/xrash/gofgen.git
$ cd gofgen
$ make
$ sudo mv bin/gofgen /usr/local/bin

Usage

gofgen generates go code loading your local files into memory at compile time

Usage:
  gofgen [flags]

Flags:
  -h, --help                  help for gofgen
      --input-dir string      dirname of the directory to read from (default ".")
      --output-file string    filename of the output file (default "./init_gofgen.go")
      --package-name string   package name to use, default value is basename of input-dirname