Merge branch 'add-symlink-hook' into 'master'

Add hook create-symlinks subcommand to create symlinks in container

See merge request nvidia/container-toolkit/container-toolkit!121

internal/discover/symlinks.go

@@ -0,0 +1,71 @@
+/**
+# Copyright (c) 2022, 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 (
+	"github.com/NVIDIA/nvidia-container-toolkit/internal/lookup"
+	"github.com/container-orchestrated-devices/container-device-interface/pkg/cdi"
+	"github.com/sirupsen/logrus"
+)
+
+type symlinks struct {
+	None
+	logger                  *logrus.Logger
+	lookup                  lookup.Locator
+	nvidiaCTKExecutablePath string
+	csvFiles                []string
+}
+
+// NewCreateSymlinksHook creates a discoverer for a hook that creates required symlinks in the container
+func NewCreateSymlinksHook(logger *logrus.Logger, csvFiles []string, cfg *Config) (Discover, error) {
+	d := symlinks{
+		logger:                  logger,
+		lookup:                  lookup.NewExecutableLocator(logger, cfg.Root),
+		nvidiaCTKExecutablePath: cfg.NVIDIAContainerToolkitCLIExecutablePath,
+		csvFiles:                csvFiles,
+	}
+
+	return &d, nil
+}
+
+// Hooks returns a hook to create the symlinks from the required CSV files
+func (d symlinks) Hooks() ([]Hook, error) {
+	hookPath := nvidiaCTKDefaultFilePath
+	targets, err := d.lookup.Locate(d.nvidiaCTKExecutablePath)
+	if err != nil {
+		d.logger.Warnf("Failed to locate %v: %v", d.nvidiaCTKExecutablePath, err)
+	} else if len(targets) == 0 {
+		d.logger.Warnf("%v not found", d.nvidiaCTKExecutablePath)
+	} else {
+		d.logger.Debugf("Found %v candidates: %v", d.nvidiaCTKExecutablePath, targets)
+		hookPath = targets[0]
+	}
+	d.logger.Debugf("Using NVIDIA Container Toolkit CLI path %v", hookPath)
+
+	args := []string{hookPath, "hook", "create-symlinks"}
+	for _, f := range d.csvFiles {
+		args = append(args, "--csv-filenames", f)
+	}
+
+	h := Hook{
+		Lifecycle: cdi.CreateContainerHook,
+		Path:      hookPath,
+		Args:      args,
+	}
+
+	return []Hook{h}, nil
+}

internal/oci/state.go

@@ -0,0 +1,73 @@
+/**
+# Copyright (c) 2022, 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 oci
+
+import (
+	"encoding/json"
+	"fmt"
+	"io"
+	"os"
+
+	"github.com/opencontainers/runtime-spec/specs-go"
+)
+
+// State stores an OCI container state. This includes the spec path and the environment
+type State specs.State
+
+// LoadContainerState loads the container state from the specified filename. If the filename is empty or '-' the state is loaded from STDIN
+func LoadContainerState(filename string) (*State, error) {
+	if filename == "" || filename == "-" {
+		return ReadContainerState(os.Stdin)
+	}
+
+	inputFile, err := os.Open(filename)
+	if err != nil {
+		return nil, fmt.Errorf("failed to open file: %v", err)
+	}
+	defer inputFile.Close()
+
+	return ReadContainerState(inputFile)
+}
+
+// ReadContainerState reads the container state from the specified reader
+func ReadContainerState(reader io.Reader) (*State, error) {
+	var s State
+
+	d := json.NewDecoder(reader)
+	if err := d.Decode(&s); err != nil {
+		return nil, fmt.Errorf("failed to decode container state: %v", err)
+	}
+
+	return &s, nil
+}
+
+// LoadSpec loads the OCI spec associated with the container state
+func (s State) LoadSpec() (*specs.Spec, error) {
+	specFilePath := GetSpecFilePath(s.Bundle)
+	specFile, err := os.Open(specFilePath)
+	if err != nil {
+		return nil, fmt.Errorf("failed to open OCI spec file: %v", err)
+	}
+	defer specFile.Close()
+
+	spec, err := LoadFrom(specFile)
+	if err != nil {
+		return nil, fmt.Errorf("failed to load OCI spec: %v", err)
+	}
+
+	return spec, nil
+}