How Can I Embed Files into My Go Binaries?

Incorporating Files into Go Binaries

Want to distribute a single executable that includes necessary text files? Go provides solutions for embedding files into binaries, tailored for various platforms.

Go 1.16 and Beyond: go:embed Directive

For Go versions 1.16 and higher, leverage the go:embed directive. It offers an elegant way to embed files:

import "embed"

//go:embed hello.txt
var s string
print(s)

//go:embed hello.txt
var b []byte
print(string(b))

//go:embed hello.txt
var f embed.FS
data, _ := f.ReadFile("hello.txt")
print(string(data))

Go 1.4 and Later: go generate for Flexibility

For Go versions 1.4 and onward, you can resort to go generate for greater flexibility. This approach involves:

1. Creating a go script that reads text files and generates string literals.
2. Using a go:generate comment in your main file to invoke the script.

This technique enables embedding multiple text files with minimal hardcoding. For instance:

main.go

package main

import "fmt"

//go:generate go run scripts/includetxt.go

func main() {
    fmt.Println(a)
    fmt.Println(b)
}

script/includetxt.go

package main

import (
    "io"
    "io/ioutil"
    "os"
    "strings"
)

func main() {
    fs, _ := ioutil.ReadDir(".")
    out, _ := os.Create("textfiles.go")
    out.Write([]byte("package main \n\nconst (\n"))
    for _, f := range fs {
        if strings.HasSuffix(f.Name(), ".txt") {
            out.Write([]byte(strings.TrimSuffix(f.Name(), ".txt") + " = `"))
            f, _ := os.Open(f.Name())
            io.Copy(out, f)
            out.Write([]byte("`\n"))
        }
    }
    out.Write([]byte(")\n"))
}

Build Commands:

$ go generate
$ go build -o main

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