Add e2e tests

vendor/github.com/gophercloud/gophercloud/openstack/utils/choose_version.go

@@ -0,0 +1,111 @@
+package utils
+
+import (
+	"fmt"
+	"strings"
+
+	"github.com/gophercloud/gophercloud"
+)
+
+// Version is a supported API version, corresponding to a vN package within the appropriate service.
+type Version struct {
+	ID       string
+	Suffix   string
+	Priority int
+}
+
+var goodStatus = map[string]bool{
+	"current":   true,
+	"supported": true,
+	"stable":    true,
+}
+
+// ChooseVersion queries the base endpoint of an API to choose the most recent non-experimental alternative from a service's
+// published versions.
+// It returns the highest-Priority Version among the alternatives that are provided, as well as its corresponding endpoint.
+func ChooseVersion(client *gophercloud.ProviderClient, recognized []*Version) (*Version, string, error) {
+	type linkResp struct {
+		Href string `json:"href"`
+		Rel  string `json:"rel"`
+	}
+
+	type valueResp struct {
+		ID     string     `json:"id"`
+		Status string     `json:"status"`
+		Links  []linkResp `json:"links"`
+	}
+
+	type versionsResp struct {
+		Values []valueResp `json:"values"`
+	}
+
+	type response struct {
+		Versions versionsResp `json:"versions"`
+	}
+
+	normalize := func(endpoint string) string {
+		if !strings.HasSuffix(endpoint, "/") {
+			return endpoint + "/"
+		}
+		return endpoint
+	}
+	identityEndpoint := normalize(client.IdentityEndpoint)
+
+	// If a full endpoint is specified, check version suffixes for a match first.
+	for _, v := range recognized {
+		if strings.HasSuffix(identityEndpoint, v.Suffix) {
+			return v, identityEndpoint, nil
+		}
+	}
+
+	var resp response
+	_, err := client.Request("GET", client.IdentityBase, &gophercloud.RequestOpts{
+		JSONResponse: &resp,
+		OkCodes:      []int{200, 300},
+	})
+
+	if err != nil {
+		return nil, "", err
+	}
+
+	var highest *Version
+	var endpoint string
+
+	for _, value := range resp.Versions.Values {
+		href := ""
+		for _, link := range value.Links {
+			if link.Rel == "self" {
+				href = normalize(link.Href)
+			}
+		}
+
+		for _, version := range recognized {
+			if strings.Contains(value.ID, version.ID) {
+				// Prefer a version that exactly matches the provided endpoint.
+				if href == identityEndpoint {
+					if href == "" {
+						return nil, "", fmt.Errorf("Endpoint missing in version %s response from %s", value.ID, client.IdentityBase)
+					}
+					return version, href, nil
+				}
+
+				// Otherwise, find the highest-priority version with a whitelisted status.
+				if goodStatus[strings.ToLower(value.Status)] {
+					if highest == nil || version.Priority > highest.Priority {
+						highest = version
+						endpoint = href
+					}
+				}
+			}
+		}
+	}
+
+	if highest == nil {
+		return nil, "", fmt.Errorf("No supported version available from endpoint %s", client.IdentityBase)
+	}
+	if endpoint == "" {
+		return nil, "", fmt.Errorf("Endpoint missing in version %s response from %s", highest.ID, client.IdentityBase)
+	}
+
+	return highest, endpoint, nil
+}