Embedded Binaries for Go

Recently a friend asked about Go packages for embedding binary data into code… As it turns out, there are a lot of options!

go-bindata

go-bindata/go-bindata

This package converts any file into Go source code, including for embedding binary data into a Go program. The file data is optionally gzip compressed before being converted to a raw byte slice. It comes with a command line tool in the go-bindata sub directory. The converted file(s) is/are embedded in a new Go source file, along with a table of contents and an Asset function, which allows quick access to the asset, based on its name.

kevinburke/go-bindata

As of the time of this writing, the most recently updated fork of the original go-bindata/go-bindata. This fork is also apparently the version trusted by Homebrew. Changes from the original package include:

• Atomic writes; generated file cannot be read while partially complete.
• Better encoding of files that contain characters in the Unicode format range.
• Generated file reports file sizes.
• Generated code is run through go fmt.
• SHA256 hashes are computed for all files and stored in the binary. You can use this to detect in-memory corruption and to provide easy cache-busting mechanisms.
• Added AssetString and MustAssetString functions.
• ByName is not public.
• Some errors in file writes were unchecked, but are now checked.
• File modes are stored in octal (0644) instead of nonsensical decimal (420)

pkger

pkger is a tool for embedding static files into Go binaries and was intended as a replacement for gobuffalo/packr. Use the pkger command to package files and the parser tool to access them after packaging. The API is modeled on the os package in the Go standard lib.

esc

esc embeds files into Go programs and provides http.FileSystem interfaces to them. It adds all named files or files recursively under named directories at the path specified. The output file provides an http.FileSystem interface with zero dependencies on packages outside the Go standard lib. After producing an output file, the assets may be accessed with the FS() function. esc appears to have had a very loyal following but has not been updated for over a year.

Conclusion (for now)

At the time of this writing the original go-bindata and pckgr libraries have the most stars on Github, though given that it is the trust choice of Homebrew, I’d recommend using the kevinburke/go-bindata package.

References

• Embedding files in binaries, Itay Shakury
• How to embed files into Go binaries, Stackoverflow
• The easiest way to embed static files into a binary file in your Golang app (no external dependencies), Vic Shostak