mirror of
https://github.com/NVIDIA/nvidia-container-toolkit
synced 2024-11-22 16:29:18 +00:00
133 lines
3.9 KiB
Go
133 lines
3.9 KiB
Go
/*
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# Copyright (c) 2021, NVIDIA CORPORATION. All rights reserved.
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#
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# Licensed under the Apache License, Version 2.0 (the "License");
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# you may not use this file except in compliance with the License.
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# You may obtain a copy of the License at
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#
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# http://www.apache.org/licenses/LICENSE-2.0
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#
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# Unless required by applicable law or agreed to in writing, software
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# distributed under the License is distributed on an "AS IS" BASIS,
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# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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# See the License for the specific language governing permissions and
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# limitations under the License.
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*/
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package main
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import (
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"fmt"
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"os"
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"os/exec"
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"strings"
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"github.com/NVIDIA/nvidia-container-toolkit/internal/oci"
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"github.com/opencontainers/runtime-spec/specs-go"
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log "github.com/sirupsen/logrus"
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)
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// nvidiaContainerRuntime encapsulates the NVIDIA Container Runtime. It wraps the specified runtime, conditionally
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// modifying the specified OCI specification before invoking the runtime.
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type nvidiaContainerRuntime struct {
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logger *log.Logger
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runtime oci.Runtime
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ociSpec oci.Spec
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}
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var _ oci.Runtime = (*nvidiaContainerRuntime)(nil)
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// newNvidiaContainerRuntime is a constructor for a standard runtime shim.
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func newNvidiaContainerRuntimeWithLogger(logger *log.Logger, runtime oci.Runtime, ociSpec oci.Spec) (oci.Runtime, error) {
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r := nvidiaContainerRuntime{
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logger: logger,
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runtime: runtime,
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ociSpec: ociSpec,
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}
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return &r, nil
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}
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// Exec defines the entrypoint for the NVIDIA Container Runtime. A check is performed to see whether modifications
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// to the OCI spec are required -- and applicable modifcations applied. The supplied arguments are then
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// forwarded to the underlying runtime's Exec method.
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func (r nvidiaContainerRuntime) Exec(args []string) error {
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if r.modificationRequired(args) {
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err := r.modifyOCISpec()
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if err != nil {
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return fmt.Errorf("error modifying OCI spec: %v", err)
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}
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}
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r.logger.Println("Forwarding command to runtime")
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return r.runtime.Exec(args)
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}
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// modificationRequired checks the intput arguments to determine whether a modification
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// to the OCI spec is required.
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func (r nvidiaContainerRuntime) modificationRequired(args []string) bool {
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if oci.HasCreateSubcommand(args) {
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r.logger.Infof("'create' command detected; modification required")
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return true
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}
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r.logger.Infof("No modification required")
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return false
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}
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// modifyOCISpec loads and modifies the OCI spec specified in the nvidiaContainerRuntime
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// struct. The spec is modified in-place and written to the same file as the input after
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// modifcationas are applied.
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func (r nvidiaContainerRuntime) modifyOCISpec() error {
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err := r.ociSpec.Load()
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if err != nil {
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return fmt.Errorf("error loading OCI specification for modification: %v", err)
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}
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err = r.ociSpec.Modify(r.addNVIDIAHook)
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if err != nil {
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return fmt.Errorf("error injecting NVIDIA Container Runtime hook: %v", err)
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}
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err = r.ociSpec.Flush()
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if err != nil {
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return fmt.Errorf("error writing modified OCI specification: %v", err)
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}
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return nil
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}
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// addNVIDIAHook modifies the specified OCI specification in-place, inserting a
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// prestart hook.
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func (r nvidiaContainerRuntime) addNVIDIAHook(spec *specs.Spec) error {
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path, err := exec.LookPath("nvidia-container-runtime-hook")
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if err != nil {
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path = hookDefaultFilePath
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_, err = os.Stat(path)
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if err != nil {
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return err
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}
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}
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r.logger.Printf("prestart hook path: %s\n", path)
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args := []string{path}
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if spec.Hooks == nil {
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spec.Hooks = &specs.Hooks{}
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} else if len(spec.Hooks.Prestart) != 0 {
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for _, hook := range spec.Hooks.Prestart {
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if !strings.Contains(hook.Path, "nvidia-container-runtime-hook") {
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continue
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}
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r.logger.Println("existing nvidia prestart hook in OCI spec file")
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return nil
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}
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}
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spec.Hooks.Prestart = append(spec.Hooks.Prestart, specs.Hook{
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Path: path,
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Args: append(args, "prestart"),
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})
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return nil
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}
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