How Can I Embed Static Files into Go Binaries Using `go:embed` and `go generate`?

Embedding Static Files into Go Binaries

Embedding static files into Go binaries ensures that all necessary files are bundled within the executable, eliminating the need for external file management. This can be achieved through the go:embed directive or the go generate technique.

Using go:embed Directive (Go 1.16 )

Starting with Go 1.16, the go:embed directive can be used to embed files directly into the binary:

//go:embed hello.txt
var s string

This embeds the contents of hello.txt into the string variable s.

Using go generate

For older versions of Go, you can embed files using go generate in conjunction with a script. Here's an example:

File Structure:

• main.go
• scripts/includetxt.go (embedding script)
• a.txt
• b.txt

main.go:

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

import "fmt"

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

includetxt.go:

package main

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

func main() {
    // Create the output file
    out, _ := os.Create("textfiles.go")
    out.Write([]byte("package main \n\nconst (\n"))

    // Iterate over .txt files in the current directory
    fs, _ := ioutil.ReadDir(".")
    for _, f := range fs {
        if strings.HasSuffix(f.Name(), ".txt") {
            // Write the embedded file contents to the output file
            out.Write([]byte(strings.TrimSuffix(f.Name(), ".txt") + ` = "`))
            f, _ := os.Open(f.Name())
            io.Copy(out, f)
            out.Write([]byte("`\n"))
        }
    }
    // Close the output file
    out.Write([]byte(")\n"))
}

To embed the files:

$ go generate
$ go build -o main

textfiles.go (Generated):

package main 

const (
a = `hello`
b = `world`
)

This embeds the contents of a.txt and b.txt into the binary as string constants, allowing them to be accessed within main.go as a and b, respectively.

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