#11 implement the vagrant.GetImageURL

vagrant/image_url.go

@@ -0,0 +1,105 @@
+package vagrant
+
+import (
+	"encoding/json"
+	"errors"
+	"fmt"
+	"io/ioutil"
+	"net/http"
+	"strings"
+)
+
+type vagrantResp struct {
+	Versions []version `json:"versions"`
+}
+type provider struct {
+	Name string `json:"name"`
+	URL  string `json:"url"`
+}
+type version struct {
+	Version   string     `json:"version"`
+	Status    string     `json:"status"`
+	Providers []provider `json:"providers"`
+}
+
+func GetImageURL(image string) (string, error) {
+
+	user, imageName, imageVersion := getImageParts(image)
+
+	req, err := http.NewRequest("GET", fmt.Sprintf("https://app.vagrantup.com/%s/boxes/%s", user, imageName), nil)
+	if err != nil {
+		return "", err
+	}
+
+	req.Header.Set("Accept", "application/json")
+
+	client := &http.Client{}
+	resp, err := client.Do(req)
+	if err != nil {
+		return "", err
+	}
+	defer resp.Body.Close()
+
+	b, err := ioutil.ReadAll(resp.Body)
+	if err != nil {
+		return "", err
+	}
+
+	var obj vagrantResp
+	if err := json.Unmarshal(b, &obj); err != nil {
+		return "", err
+	}
+
+	p, err := filterByVersion(obj, user, imageName, imageVersion)
+	if err != nil {
+		return "", err
+	}
+
+	return p.URL, nil
+}
+
+func filterByVersion(resp vagrantResp, user, imageName, imageVersion string) (provider, error) {
+
+	if len(resp.Versions) == 0 {
+		return provider{}, errors.New("vagrant response contains no versions")
+	}
+
+	if imageVersion == "" {
+		// get latest version
+		return getVirtualBoxProvider(resp.Versions[0].Providers)
+	} else {
+		for _, v := range resp.Versions {
+			if v.Version == imageVersion {
+				return getVirtualBoxProvider(v.Providers)
+			}
+		}
+		return provider{}, fmt.Errorf("vagrant image version not found, "+
+			"check correct version number here: https://app.vagrantup.com/%s/boxes/%s", user, imageName)
+	}
+}
+
+func getVirtualBoxProvider(providers []provider) (provider, error) {
+	for _, p := range providers {
+		if p.Name == "virtualbox" {
+			return p, nil
+		}
+	}
+	return provider{}, errors.New("VirtualBox image not found for specified version")
+}
+
+// getImageParts syntax vagrant/USER/BOX:VERSION e.g.: vagrant/ubuntu/trusty64:20190429.0.1
+// returns USER, BOX, VERSION (ubuntu, trusty64, 20190429.0.1)
+func getImageParts(image string) (user string, imageName string, imageVersion string) {
+
+	parts := strings.Split(image, "/")
+	user = parts[1]
+	box := parts[2]
+
+	boxParts := strings.Split(box, ":")
+	imageName = boxParts[0]
+
+	if len(boxParts) > 1 {
+		imageVersion = boxParts[1]
+	}
+	return user, imageName, imageVersion
+}