stuffbin

stuffbin is a utility + package to compress and embed static files and assets into Go binaries for distribution. It supports falling back to the local file system when no embedded assets are available, for instance, in development mode. stuffbin is inspired by zgok but is much cleaner and leaner.

How does it work?

stuffbin compresses and embeds arbitrary files to the end of Go binaries. This does not affect the normal execution of the binary by the operating system as it is aware of its original size. The compressed data that is appended beyond its original size is simply ignored. When a stuffed application is executed, stuffbin reads the compressed bytes from self (the executable), uncompresses the files on the fly into an in-memory filesystem and provides a simple FileSystem interface to access them. This enables complex Go applications that have external file dependencies to be shipped a single fat binary, commonly, web applications that have static file and template dependencies.

Built in ZIP compression
A virtual filesystem abstraction to access embedded files
Add static assets from nested directories recursively
Re-path files and whole directories with the :suffix format, eg: ../my/original/file.txt:/my/virtual/file.txt and /my/nested/dir:/virtual/dir
Template parsing helper similar to template.ParseGlob() to parse templates from the virtual filesystem
Launch an http.FileServer for serving static files
Gracefully failover to the local file system in the absence of embedded assets
CLI to stuff, unstuff and extract, and list stuffed files in binaries

Installation

go get -u github.com/knadh/stuffbin/...

Usage

Stuffing and embedding

# -a, -in, and -out params followed by the paths of files to embed.
# To normalize paths, aliases can be suffixed with a colon.
stuffbin -a stuff -in /path/to/exe -out /path/to/new.exe \
    static/file1.css static/file2.pdf /somewhere/else/file3.txt:/static/file3.txt

List files in a stuffed binary

stuffbin -a id -in /path/to/new/exe

Extract stuffed files from a binary

stuffbin -a unstuff -in /path/to/new/exe -out assets.zip

In the application

To test this, cd into ./mock and run go run mock.go

package main

import (
	"fmt"
	"log"
	"net/http"
	"os"

	"github.com/knadh/stuffbin"
)

func main() {
	// Read stuffed data from self.
	fs, err := stuffbin.UnStuff(os.Args[0])
	if err != nil {
		// Binary is unstuffed or is running in dev mode.
		// Can halt here or fall back to the local filesystem.
		if err == stuffbin.ErrNoID {
			// First argument is to the root to mount the files in the FileSystem
			// and the rest of the arguments are paths to embed.
			fs, err = stuffbin.NewLocalFS("/",
				"./", "bar.txt:/virtual/path/bar.txt")
			if err != nil {
				log.Fatalf("error falling back to local filesystem: %v", err)
			}
		} else {
			log.Fatalf("error reading stuffed binary: %v", err)
		}
	}

	fmt.Println("loaded files", fs.List())
	// Read the file 'foo'.
	f, err := fs.Get("foo.txt")
	if err != nil {
		log.Fatalf("error reading foo.txt: %v", err)
	}
	log.Println("foo.txt =", string(f.ReadBytes()))

	// Read the file 'bar'.
	f, err = fs.Get("/virtual/path/bar.txt")
	if err != nil {
		log.Fatalf("error reading /virtual/path/bar.txt: %v", err)
	}
	log.Println("/virtual/path/bar.txt =", string(f.ReadBytes()))

	fmt.Println("stuffed files:")
	for _, f := range fs.List() {
		fmt.Println("\t", f)
	}

	// Compile templates with the helpers:
	// err, tpl := stuffbin.ParseTemplatesGlob(nil, fs, "/templates/*.html")
	//
	// Template func map.
	// mp := map[string]interface{}{
	// 	"Foo": func() string {
	// 		return "func"
	// 	},
	// }
	// err, tpl := stuffbin.ParseTemplates(mp, fs, "/templates/index.html", "/templates/hello.html")

	// Expose an HTTP file server.
	// Try http://localhost:8000/static/foo.txt
	// Try http://localhost:8000/static/virtual/path/bar.txt
	// Try http://localhost:8000/static/subdir/baz.txt
	http.Handle("/static/", http.StripPrefix("/static/", fs.FileServer()))
	log.Println("listening on :8000")
	http.ListenAndServe(":8000", nil)
}

License

Licensed under the MIT License.

vividvilla / stuffbin