rancherOS/util/network/network.go

package network

import (
	"errors"
	"fmt"
	"io/ioutil"
	"net"
	"net/http"
	"strings"
	"time"

	yaml "github.com/cloudfoundry-incubator/candiedyaml"

	log "github.com/Sirupsen/logrus"
	"github.com/rancher/os/config"
)

var (
	ErrNoNetwork = errors.New("Networking not available to load resource")
	ErrNotFound  = errors.New("Failed to find resource")
)

func GetServices(urls []string) ([]string, error) {
	return getServices(urls, "services")
}

func GetConsoles(urls []string) ([]string, error) {
	return getServices(urls, "consoles")
}

func getServices(urls []string, key string) ([]string, error) {
	result := []string{}

	for _, url := range urls {
		indexUrl := fmt.Sprintf("%s/index.yml", url)
		content, err := LoadResource(indexUrl, true)
		if err != nil {
			log.Errorf("Failed to load %s: %v", indexUrl, err)
			continue
		}

		services := make(map[string][]string)
		err = yaml.Unmarshal(content, &services)
		if err != nil {
			log.Errorf("Failed to unmarshal %s: %v", indexUrl, err)
			continue
		}

		if list, ok := services[key]; ok {
			result = append(result, list...)
		}
	}

	return result, nil
}

func loadFromNetwork(location string) ([]byte, error) {
	bytes := cacheLookup(location)
	if bytes != nil {
		return bytes, nil
	}

	var err error
	for i := 0; i < 300; i++ {
		net.UpdateDnsConf()

		var resp *http.Response
		resp, err = http.Get(location)
		if err == nil {
			defer resp.Body.Close()
			if resp.StatusCode != http.StatusOK {
				return nil, fmt.Errorf("non-200 http response: %d", resp.StatusCode)
			}

			bytes, err := ioutil.ReadAll(resp.Body)
			if err != nil {
				return nil, err
			}

			cacheAdd(location, bytes)
			return bytes, nil
		}

		time.Sleep(100 * time.Millisecond)
	}

	return nil, err
}

func LoadResource(location string, network bool) ([]byte, error) {
	if strings.HasPrefix(location, "http:/") || strings.HasPrefix(location, "https:/") {
		if !network {
			return nil, ErrNoNetwork
		}
		return loadFromNetwork(location)
	} else if strings.HasPrefix(location, "/") {
		return ioutil.ReadFile(location)
	}

	return nil, ErrNotFound
}

func serviceUrl(url, name string) string {
	return fmt.Sprintf("%s/%s/%s.yml", url, name[0:1], name)
}

func LoadServiceResource(name string, useNetwork bool, cfg *config.CloudConfig) ([]byte, error) {
	bytes, err := LoadResource(name, useNetwork)
	if err == nil {
		log.Debugf("Loaded %s from %s", name, name)
		return bytes, nil
	}
	if err == ErrNoNetwork || !useNetwork {
		return nil, ErrNoNetwork
	}

	urls := cfg.Rancher.Repositories.ToArray()
	for _, url := range urls {
		serviceUrl := serviceUrl(url, name)
		bytes, err = LoadResource(serviceUrl, useNetwork)
		if err == nil {
			log.Debugf("Loaded %s from %s", name, serviceUrl)
			return bytes, nil
		}
	}

	return nil, err
}