xgo/xgo.go

110 lines
3.0 KiB
Go

// 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 (
"bytes"
"flag"
"fmt"
"io"
"log"
"os"
"os/exec"
)
// Cross compilation docker containers
var dockerBase = "karalabe/xgo-base"
var dockerDist = "karalabe/xgo-"
// Command line arguments to fine tune the compilation
var goVersion = flag.String("go", "latest", "Go release to use for cross compilation")
func main() {
flag.Parse()
// Ensure docker is available
if err := checkDocker(); err != nil {
log.Fatalf("Failed to check docker installation: %v.", err)
}
// Validate the command line arguments
if len(flag.Args()) != 1 {
log.Fatalf("Usage: %s [options] <go import path>", os.Args[0])
}
// Check that all required images are available
found, err := checkDockerImage(dockerDist + *goVersion)
switch {
case err != nil:
log.Fatalf("Failed to check docker image availability: %v.", err)
case !found:
fmt.Println("not found!")
if err := pullDockerImage(dockerDist + *goVersion); err != nil {
log.Fatalf("Failed to pull docker image from the registry: %v.", err)
}
default:
fmt.Println("found.")
}
// Cross compile the requested package into the local folder
if err := compile(flag.Args()[0]); err != nil {
log.Fatalf("Failed to cross compile package: %v.", err)
}
}
// Checks whether a docker installation can be found and is functional.
func checkDocker() error {
fmt.Println("Checking docker installation...")
if err := run(exec.Command("docker", "version")); err != nil {
return err
}
fmt.Println()
return nil
}
// Checks whether a required docker image is available locally.
func checkDockerImage(image string) (bool, error) {
fmt.Printf("Checking for required docker image %s... ", image)
out, err := exec.Command("docker", "images", "--no-trunc").Output()
if err != nil {
return false, err
}
return bytes.Contains(out, []byte(image)), nil
}
// Pulls an image from the docker registry.
func pullDockerImage(image string) error {
fmt.Printf("Pulling %s from docker registry...\n", image)
fmt.Printf("Note, this may take some time, but due to a docker bug, progress cannot be displayed.\n")
return run(exec.Command("docker", "pull", image))
}
// Cross compiles a requested package into the current working directory.
func compile(path string) error {
folder, err := os.Getwd()
if err != nil {
log.Fatalf("Failed to retrieve the working directory: %v.", err)
}
fmt.Printf("Cross compiling %s...\n", path)
if err := run(exec.Command("docker", "run", "-v", folder+":/build", dockerDist+*goVersion, path)); err != nil {
return err
}
return nil
}
// 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()
}