nvidia-container-toolkit/internal/discover/hooks.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 discover

import (
	"path/filepath"

	"github.com/NVIDIA/nvidia-container-toolkit/internal/lookup"
	"github.com/container-orchestrated-devices/container-device-interface/pkg/cdi"
	"github.com/sirupsen/logrus"
)

const (
	nvidiaCTKExecutable      = "nvidia-ctk"
	nvidiaCTKDefaultFilePath = "/usr/bin/nvidia-ctk"
)

var _ Discover = (*Hook)(nil)

// Devices returns an empty list of devices for a Hook discoverer.
func (h Hook) Devices() ([]Device, error) {
	return nil, nil
}

// Mounts returns an empty list of mounts for a Hook discoverer.
func (h Hook) Mounts() ([]Mount, error) {
	return nil, nil
}

// Hooks allows the Hook type to also implement the Discoverer interface.
// It returns a single hook
func (h Hook) Hooks() ([]Hook, error) {
	return []Hook{h}, nil
}

// CreateCreateSymlinkHook creates a hook which creates a symlink from link -> target.
func CreateCreateSymlinkHook(nvidiaCTKPath string, links []string) Discover {
	if len(links) == 0 {
		return None{}
	}

	var args []string
	for _, link := range links {
		args = append(args, "--link", link)
	}
	return CreateNvidiaCTKHook(
		nvidiaCTKPath,
		"create-symlinks",
		args...,
	)
}

// CreateNvidiaCTKHook creates a hook which invokes the NVIDIA Container CLI hook subcommand.
func CreateNvidiaCTKHook(nvidiaCTKPath string, hookName string, additionalArgs ...string) Hook {
	return Hook{
		Lifecycle: cdi.CreateContainerHook,
		Path:      nvidiaCTKPath,
		Args:      append([]string{filepath.Base(nvidiaCTKPath), "hook", hookName}, additionalArgs...),
	}
}

// FindNvidiaCTK locates the nvidia-ctk executable to be used in hooks.
// If an nvidia-ctk path is specified as an absolute path, it is used directly
// without checking for existence of an executable at that path.
func FindNvidiaCTK(logger *logrus.Logger, nvidiaCTKPath string) string {
	if filepath.IsAbs(nvidiaCTKPath) {
		logger.Debugf("Using specified NVIDIA Container Toolkit CLI path %v", nvidiaCTKPath)
		return nvidiaCTKPath
	}

	if nvidiaCTKPath == "" {
		nvidiaCTKPath = nvidiaCTKExecutable
	}
	logger.Debugf("Locating NVIDIA Container Toolkit CLI as %v", nvidiaCTKPath)
	lookup := lookup.NewExecutableLocator(logger, "")
	hookPath := nvidiaCTKDefaultFilePath
	targets, err := lookup.Locate(nvidiaCTKPath)
	if err != nil {
		logger.Warnf("Failed to locate %v: %v", nvidiaCTKPath, err)
	} else if len(targets) == 0 {
		logger.Warnf("%v not found", nvidiaCTKPath)
	} else {
		logger.Debugf("Found %v candidates: %v", nvidiaCTKPath, targets)
		hookPath = targets[0]
	}
	logger.Debugf("Using NVIDIA Container Toolkit CLI path %v", hookPath)

	return hookPath
}