openstack: read credentials from clouds.yaml

internal/cloud/openstack/clouds/read.go

@@ -0,0 +1,59 @@
+/*
+Copyright (c) Edgeless Systems GmbH
+
+SPDX-License-Identifier: AGPL-3.0-only
+*/
+package clouds
+
+import (
+	"fmt"
+	"os"
+	"path/filepath"
+
+	"github.com/mitchellh/go-homedir"
+
+	"github.com/edgelesssys/constellation/v2/internal/file"
+)
+
+// ReadCloudsYAML reads a clouds.yaml file and returns its contents.
+func ReadCloudsYAML(fileHandler file.Handler, path string) (Clouds, error) {
+	// Order of operations as performed by the OpenStack CLI:
+
+	// Define a search path for clouds.yaml:
+	// 1. If OS_CLIENT_CONFIG_FILE is set, use it as search path
+	// 2. Otherwise, use the following paths:
+	//    - current directory
+	//    - `openstack` directory under standard user config directory (e.g. ~/.config/openstack)
+	//    - /etc/openstack (Unix only)
+
+	var searchPaths []string
+	if path != "" {
+		expanded, err := homedir.Expand(path)
+		if err == nil {
+			searchPaths = append(searchPaths, expanded)
+		} else {
+			searchPaths = append(searchPaths, path)
+		}
+	} else if osClientConfigFile := os.Getenv("OS_CLIENT_CONFIG_FILE"); osClientConfigFile != "" {
+		searchPaths = append(searchPaths, filepath.Join(osClientConfigFile, "clouds.yaml"))
+	} else {
+		searchPaths = append(searchPaths, "clouds.yaml")
+		confDir, err := os.UserConfigDir()
+		if err != nil {
+			return Clouds{}, fmt.Errorf("getting user config directory: %w", err)
+		}
+		searchPaths = append(searchPaths, filepath.Join(confDir, "openstack", "clouds.yaml"))
+		if os.PathSeparator == '/' {
+			searchPaths = append(searchPaths, "/etc/openstack/clouds.yaml")
+		}
+	}
+
+	var cloudsYAML Clouds
+	for _, path := range searchPaths {
+		if err := fileHandler.ReadYAML(path, &cloudsYAML); err == nil {
+			return cloudsYAML, nil
+		}
+	}
+
+	return Clouds{}, fmt.Errorf("clouds.yaml not found in search paths: %v", searchPaths)
+}