Reuse mount discovery for driver libraries

This change implements the discovery of versioned driver libaries
by reusing the mounts and update ldcache discoverers use for, for example,
CVS file discovery. This allows the container paths to be correctly generated
without requiring specific manipulation.

Signed-off-by: Evan Lezar <elezar@nvidia.com>

cmd/nvidia-ctk/cdi/generate/driver.go

@@ -28,15 +28,6 @@ import (
 	"gitlab.com/nvidia/cloud-native/go-nvlib/pkg/nvml"
 )
 
-type driverLibraries struct {
-	logger        *logrus.Logger
-	root          string
-	nvidiaCTKPath string
-	libraries     []string
-}
-
-var _ discover.Discover = (*driverLibraries)(nil)
-
 // NewDriverDiscoverer creates a discoverer for the libraries and binaries associated with a driver installation.
 // The supplied NVML Library is used to query the expected driver version.
 func NewDriverDiscoverer(logger *logrus.Logger, root string, nvidiaCTKPath string, nvmllib nvml.Interface) (discover.Discover, error) {
@@ -64,20 +55,34 @@ func NewDriverDiscoverer(logger *logrus.Logger, root string, nvidiaCTKPath strin
 }
 
 // NewDriverLibraryDiscoverer creates a discoverer for the libraries associated with the specified driver version.
-func NewDriverLibraryDiscoverer(logger *logrus.Logger, root string, nvidiaCTKPath, version string) (discover.Discover, error) {
+func NewDriverLibraryDiscoverer(logger *logrus.Logger, root string, nvidiaCTKPath string, version string) (discover.Discover, error) {
-	libraries, err := findVersionLibs(logger, root, version)
+	libraryPaths, err := getVersionLibs(logger, root, version)
 	if err != nil {
 		return nil, fmt.Errorf("failed to get libraries for driver version: %v", err)
 	}
 
-	d := driverLibraries{
+	libraries := discover.NewMounts(
-		logger:        logger,
+		logger,
-		root:          root,
+		lookup.NewFileLocator(
-		nvidiaCTKPath: nvidiaCTKPath,
+			lookup.WithLogger(logger),
-		libraries:     libraries,
+			lookup.WithRoot(root),
-	}
+		),
+		root,
+		libraryPaths,
+	)
 
-	return &d, nil
+	cfg := &discover.Config{
+		Root:          root,
+		NvidiaCTKPath: nvidiaCTKPath,
+	}
+	hooks, _ := discover.NewLDCacheUpdateHook(logger, libraries, cfg)
+
+	d := discover.Merge(
+		libraries,
+		hooks,
+	)
+
+	return d, nil
 }
 
 // NewDriverFirmwareDiscoverer creates a discoverer for GSP firmware associated with the specified driver version.
@@ -110,36 +115,10 @@ func NewDriverBinariesDiscoverer(logger *logrus.Logger, root string) discover.Di
 	)
 }
 
-// Devices are empty for this discoverer
+// getVersionLibs checks the LDCache for libraries ending in the specified driver version.
-func (d *driverLibraries) Devices() ([]discover.Device, error) {
+// Although the ldcache at the specified root is queried, the paths are returned relative to this root.
-	return nil, nil
+// This allows the standard mount location logic to be used for resolving the mounts.
-}
+func getVersionLibs(logger *logrus.Logger, root string, version string) ([]string, error) {
-
-// Mounts returns the mounts for the driver libraries
-func (d *driverLibraries) Mounts() ([]discover.Mount, error) {
-	var mounts []discover.Mount
-	for _, d := range d.libraries {
-		mount := discover.Mount{
-			HostPath: d,
-			Path:     d,
-		}
-		mounts = append(mounts, mount)
-	}
-
-	return mounts, nil
-}
-
-// Hooks returns a hook that updates the LDCache for the specified driver library paths.
-func (d *driverLibraries) Hooks() ([]discover.Hook, error) {
-	hook := discover.CreateLDCacheUpdateHook(
-		d.nvidiaCTKPath,
-		d.libraries,
-	)
-
-	return []discover.Hook{hook}, nil
-}
-
-func findVersionLibs(logger *logrus.Logger, root string, version string) ([]string, error) {
 	logger.Infof("Using driver version %v", version)
 
 	cache, err := ldcache.New(logger, root)
@@ -164,5 +143,14 @@ func findVersionLibs(logger *logrus.Logger, root string, version string) ([]stri
 		}
 	}
 
+	if root == "/" || root == "" {
 		return libs, nil
 	}
+
+	var relative []string
+	for _, l := range libs {
+		relative = append(relative, strings.TrimPrefix(l, root))
+	}
+
+	return relative, nil
+}