Add endpoint discovery support

stephenfin · stephenfin · commit f28c96333f81 · 2025-05-16T12:48:47.000+01:00
This is simpler than expected. Effectively, for each potential endpoint,
we retrieve the version document from the root URL and parse the version
information, if any, from it, comparing it against the version expected.

Signed-off-by: Stephen Finucane &lt;stephenfin@redhat.com&gt;
diff --git a/openstack/endpoint.go b/openstack/endpoint.go
@@ -1,13 +1,34 @@
 package openstack
 
 import (
+	"context"
 	"slices"
 
 	"github.com/gophercloud/gophercloud/v2"
 	tokens2 "github.com/gophercloud/gophercloud/v2/openstack/identity/v2/tokens"
 	tokens3 "github.com/gophercloud/gophercloud/v2/openstack/identity/v3/tokens"
+	"github.com/gophercloud/gophercloud/v2/openstack/utils"
 )
 
+func endpointSupportsVersion(ctx context.Context, client *gophercloud.ProviderClient, serviceType, endpointURL string, expectedVersion int) (bool, error) {
+	// Swift doesn't support version discovery :(
+	if expectedVersion == 0 || serviceType == "object-store" {
+		return true, nil
+	}
+
+	endpointURL, err := utils.BaseVersionedEndpoint(endpointURL)
+	if err != nil {
+		return false, err
+	}
+
+	supportedMicroversions, err := utils.GetServiceVersions(ctx, client, endpointURL)
+	if err != nil {
+		return false, err
+	}
+
+	return supportedMicroversions.MinMajor == 0 || supportedMicroversions.MinMajor == expectedVersion, nil
+}
+
 /*
 V2Endpoint discovers the endpoint URL for a specific service from a
 ServiceCatalog acquired during the v2 identity service.
@@ -18,7 +39,7 @@ criteria and when none do. The minimum that can be specified is a Type, but you
 will also often need to specify a Name and/or a Region depending on what's
 available on your OpenStack deployment.
 */
-func V2Endpoint(catalog *tokens2.ServiceCatalog, opts gophercloud.EndpointOpts) (string, error) {
+func V2Endpoint(ctx context.Context, client *gophercloud.ProviderClient, catalog *tokens2.ServiceCatalog, opts gophercloud.EndpointOpts) (string, error) {
 	// Extract Endpoints from the catalog entries that match the requested Type, Name if provided, and Region if provided.
 	//
 	// If multiple endpoints are found, we return the first result and disregard the rest.
@@ -45,6 +66,14 @@ func V2Endpoint(catalog *tokens2.ServiceCatalog, opts gophercloud.EndpointOpts)
 					return "", err
 				}
 
+				endpointSupportsVersion, err := endpointSupportsVersion(ctx, client, entry.Type, endpointURL, opts.Version)
+				if err != nil {
+					return "", err
+				}
+				if !endpointSupportsVersion {
+					continue
+				}
+
 				return endpointURL, nil
 			}
 		}
@@ -65,7 +94,7 @@ criteria and when none do. The minimum that can be specified is a Type, but you
 will also often need to specify a Name and/or a Region depending on what's
 available on your OpenStack deployment.
 */
-func V3Endpoint(catalog *tokens3.ServiceCatalog, opts gophercloud.EndpointOpts) (string, error) {
+func V3Endpoint(ctx context.Context, client *gophercloud.ProviderClient, catalog *tokens3.ServiceCatalog, opts gophercloud.EndpointOpts) (string, error) {
 	if opts.Availability != gophercloud.AvailabilityAdmin &&
 		opts.Availability != gophercloud.AvailabilityPublic &&
 		opts.Availability != gophercloud.AvailabilityInternal {
@@ -90,7 +119,17 @@ func V3Endpoint(catalog *tokens3.ServiceCatalog, opts gophercloud.EndpointOpts)
 					continue
 				}
 
-				return gophercloud.NormalizeURL(endpoint.URL), nil
+				endpointURL := gophercloud.NormalizeURL(endpoint.URL)
+
+				endpointSupportsVersion, err := endpointSupportsVersion(ctx, client, entry.Type, endpointURL, opts.Version)
+				if err != nil {
+					return "", err
+				}
+				if !endpointSupportsVersion {
+					continue
+				}
+
+				return endpointURL, nil
 			}
 		}
 	}
