example.go

// Package main contains an example use of this library; it
// prints the current Fedora CoreOS EC2(AWS) x86_64 AMI in the
// us-east-2 region.
package main

import (
	"encoding/json"
	"fmt"
	"io/ioutil"
	"net/http"
	"os"

	"github.com/coreos/stream-metadata-go/fedoracoreos"
	"github.com/coreos/stream-metadata-go/stream"
)

const (
	targetArch = "x86_64"
	region     = "us-east-2"
)

func run() error {
	streamurl := fedoracoreos.GetStreamURL(fedoracoreos.StreamStable)
	resp, err := http.Get(streamurl.String())
	if err != nil {
		return err
	}
	body, err := ioutil.ReadAll(resp.Body)
	resp.Body.Close()
	if err != nil {
		return err
	}

	var fcosstable stream.Stream
	err = json.Unmarshal(body, &fcosstable)
	if err != nil {
		return err
	}
	arch, ok := fcosstable.Architectures[targetArch]
	if !ok {
		return fmt.Errorf("No %s architecture in stream", targetArch)
	}
	awsimages := arch.Images.Aws
	if awsimages == nil {
		return fmt.Errorf("No %s AWS images in stream", targetArch)
	}
	var regionVal stream.AwsRegionImage
	if regionVal, ok = awsimages.Regions[region]; !ok {
		return fmt.Errorf("No %s AWS images in region %s", targetArch, region)
	}
	fmt.Printf("%s\n", regionVal.Image)

	return nil
}

func main() {
	if err := run(); err != nil {
		fmt.Fprintf(os.Stderr, "%v\n", err)
		os.Exit(1)
	}
}