As a Director of Engineering, I’m always looking for ways to simplify our development and deployment processes. The more we can reduce external dependencies and streamline our tooling, the more reliable and maintainable our systems become. One of the most elegant solutions I’ve seen for this challenge comes from the Go ecosystem: embedding executables directly inside a Go binary.

This technique is a game-changer for building self-contained applications. Imagine deploying a single, static binary that contains not only your core application but also all the necessary command-line tools or other executables it depends on. No more complex installation scripts, no more PATH management, and no more version mismatches in production.

Since Go 1.16, the embed package has provided a first-class, compile-time mechanism for bundling assets into a program. While often used for web templates or configuration files, its ability to embed any file, including other binaries, is where its true power lies for infrastructure tooling.

How It Works: A Practical Example

Let’s look at a straightforward example. Here, we have a Go program that embeds a simple hello-world executable and runs it.

package main

import (
	"embed"
	"os"
	"os/exec"
	"path/filepath"
)

//go:embed assets/hello-world
var embeddedFS embed.FS

func main() {
	// 1. Read the embedded binary’s bytes.
	bin, _ := embeddedFS.ReadFile("assets/hello-world")

	// 2. Write to a temporary file.
	tmpDir, _ := os.MkdirTemp("", "embedded-bin-*")
	tmpPath := filepath.Join(tmpDir, "hello-world")
	_ = os.WriteFile(tmpPath, bin, 0755) // mark it executable (Unix)

	// 3. Run it.
	cmd := exec.Command(tmpPath, "--arg1", "value")
	cmd.Stdout, cmd.Stderr = os.Stdout, os.Stderr
	if err := cmd.Run(); err != nil {
		panic(err)
	}

	// 4. Clean up (optional—tmpDir auto-deleted on reboot anyway).
	_ = os.RemoveAll(tmpDir)
}

Breaking Down the Code

Let’s walk through what’s happening here.

  1. The //go:embed Directive: This is the magic key. It’s a compiler directive that instructs the Go toolchain to embed the file at assets/hello-world into the embeddedFS variable of type embed.FS. This happens at compile time, so the binary’s contents are baked directly into our program.

  2. Read the Binary from Memory: In the main function, embeddedFS.ReadFile("assets/hello-world") accesses the embedded file system and reads the raw bytes of our executable into the bin variable.

  3. Write to a Temporary File: The operating system can’t execute a program that exists only in memory. It needs a file on the filesystem. We create a temporary directory using os.MkdirTemp and write the binary’s bytes to a new file within it. The most critical step here is passing the file mode 0755, which marks the file as executable on Unix-like systems.

  4. Execute the Command: With our binary now on disk, we can use the standard os/exec package to run it just like any other program. We create a new exec.Command, passing the path to our temporary executable and any arguments it needs. We also pipe its standard output and error streams to our main program’s streams so we can see the output.

  5. Clean Up: Finally, good practice dictates that we clean up after ourselves. os.RemoveAll(tmpDir) deletes the temporary directory and the executable within it, leaving the system clean.

Why This Matters for Engineering Teams

Adopting this pattern offers several powerful advantages:

  • Zero-Dependency Deployments: Your Go application becomes a truly self-contained unit. You can ship a single file without asking users or CI/CD systems to install kubectl, helm, gcloud, or any other CLI tool your application might need to orchestrate its work.
  • Atomic and Reliable: By bundling dependencies, you create an atomic unit. The version of the tool you tested with in development is the exact same version that will run in production, eliminating an entire class of potential environment-related bugs.
  • Simplified Operations: It removes complexity from your deployment pipeline and runtime environment. There’s no need to manage system paths or check for the existence of a dependency; your program inherently knows where to find its tools because it brought them along.

In conclusion, embedding executables is more than just a neat trick; it’s a robust strategy for building simpler, more reliable software. It’s a perfect example of Go’s pragmatic philosophy, providing developers with the tools to solve real-world operational challenges with clean, effective code.