Add a simple wrapper around the docker command.

xgo.go

@@ -0,0 +1,55 @@
+// Go CGO cross compiler
+// Copyright (c) 2014 Péter Szilágyi. All rights reserved.
+//
+// Released under the MIT license.
+
+// Wrapper around the GCO cross compiler docker container.
+package main
+
+import (
+	"fmt"
+	"io"
+	"log"
+	"os"
+	"os/exec"
+)
+
+// Docker container configured for cross compilation.
+var container = "karalabe/xgo"
+
+func main() {
+	// Make sure docker is actually available on the system
+	fmt.Println("Checking docker installation...")
+	if err := run(exec.Command("docker", "version")); err != nil {
+		log.Fatalf("Failed to check docker installation: %v.", err)
+	}
+	// Fetch and configure the compilation settings
+	if len(os.Args) != 2 {
+		log.Fatalf("Usage: %s <go import path>", os.Args[0])
+	}
+	path := os.Args[1]
+	pwd, err := os.Getwd()
+	if err != nil {
+		log.Fatalf("Failed to retrieve the working directory: %v.", err)
+	}
+	// Cross compile the requested package into the local folder
+	fmt.Println("Cross compiling", path)
+	if err := run(exec.Command("docker", "run", "-v", pwd+":/build", container, path)); err != nil {
+		log.Fatalf("Failed to cross compile package: %v.", err)
+	}
+}
+
+// Executes a command synchronously, redirecting its output to stdout.
+func run(cmd *exec.Cmd) error {
+	if out, err := cmd.StdoutPipe(); err != nil {
+		return err
+	} else {
+		go io.Copy(os.Stdout, out)
+	}
+	if out, err := cmd.StderrPipe(); err != nil {
+		return err
+	} else {
+		go io.Copy(os.Stderr, out)
+	}
+	return cmd.Run()
+}