embedfs

Embedfs

This is a utility for packaging a directory hierarchy as resources within a single golang executable. The utility works by generating golang source code that contains the binary data of the files to be embedded (e.g. a png image). The embedded file can be accessed via import <path> statements in your go program as if opening a directory (e.g. net/http library's http.Dir("path/on/disk")), except the file content is embedded inside the go executable.

There's no dependency on another package. The utility generates code that implements the following interfaces, in addition to the actual binary data of the embedded files:

• os.FileInfo
• http.File
• http.FileSystem

As an example, Twitter's Bootstrap example site (http://examples.getbootstrap.com/) is included and can be built as a single executable. The example, bootstrap-examples-master.go accesses the embedded files like so:

import (
bootstrap_examples "github.com/qorio/embedfs/examples/bootstrap-examples-master"
)

// ....

fs := bootstrap_examples.Dir(".")
http.Handle("/", http.FileServer(fs))

Building

The embedfs command (main.go) itself depends on one of the source files (pkg/embedfs/fs.go) to be packaged within the binary -- so that it can generate the filesystem api implementations.

The embedded filesystem that the program depends on is in the resources directory. To embed the fs.go source code itself in the executable:

cd pkg
go run ../main.go -destDir=../resources -match="/fs\\.go$" -generate=true .

This will generate the go files to be compiled. Then,

cd .. # back to where main.go is
go build -o embedfs main.go

Running the Twitter Bootstrap Example

The Twitter Bootstrap example site is included in the examples folder, along with a simple server bootstrap-examples-master.go. To embed the entire site into a single server, do

cd examples
unzip bootstrap-examples-master.zip
../embedfs -match=".*" -generate=true bootstrap-examples-master
go run main/bootstrap-examples-master.go

To prove that the entire site is embedded into a single executable, just build the example

go build -o bootstrap-examples main/bootstrap-examples-master.go

Then run the resulting executable, bootstrap-examples:

./bootstrap-examples

and open the browser at localhost