nvidia-container-toolkit/pkg/nvcdi/transform/root.go
Christopher Desiniotis 0516fc96ca Add Transform interface and initial implemention for a root transform
Signed-off-by: Christopher Desiniotis <cdesiniotis@nvidia.com>
2023-02-28 08:56:13 -08:00

96 lines
2.5 KiB
Go

/**
# Copyright (c) NVIDIA CORPORATION. All rights reserved.
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
**/
package transform
import (
"fmt"
"path/filepath"
"strings"
"github.com/container-orchestrated-devices/container-device-interface/specs-go"
)
type rootTransformer struct {
root string
targetRoot string
}
var _ Transformer = (*rootTransformer)(nil)
// NewRootTransformer creates a new transformer for modifying
// the root for paths in a CDI spec.
func NewRootTransformer(root string, targetRoot string) Transformer {
t := rootTransformer{
root: root,
targetRoot: targetRoot,
}
return t
}
// Transform replaces the root in a spec with a new root.
// It walks the spec and replaces all host paths that start with root with the target root.
func (t rootTransformer) Transform(spec *specs.Spec) error {
if spec == nil {
return nil
}
for _, d := range spec.Devices {
if err := t.applyToEdits(&d.ContainerEdits); err != nil {
return fmt.Errorf("failed to apply root transform to device %s: %w", d.Name, err)
}
}
if err := t.applyToEdits(&spec.ContainerEdits); err != nil {
return fmt.Errorf("failed to apply root transform to spec: %w", err)
}
return nil
}
func (t rootTransformer) applyToEdits(edits *specs.ContainerEdits) error {
for i, dn := range edits.DeviceNodes {
dn.HostPath = t.transformPath(dn.HostPath)
edits.DeviceNodes[i] = dn
}
for i, hook := range edits.Hooks {
hook.Path = t.transformPath(hook.Path)
// TODO: The args need more attention. For the hooks that create symlinks we would have to transform these too.
var args []string
for _, arg := range hook.Args {
args = append(args, t.transformPath(arg))
}
hook.Args = args
edits.Hooks[i] = hook
}
for i, mount := range edits.Mounts {
mount.HostPath = t.transformPath(mount.HostPath)
edits.Mounts[i] = mount
}
return nil
}
func (t rootTransformer) transformPath(path string) string {
if !strings.HasPrefix(path, t.root) {
return path
}
return filepath.Join(t.targetRoot, strings.TrimPrefix(path, t.root))
}