nvidia-container-toolkit/cmd/nvidia-container-runtime/nvcr.go
Evan Lezar 4177fddcc4 Import modifying runtime abstraction from experimental runtime
This change imports the modifying runtime abstraction from the
experimental branch. This encapsulates the checks for whether
modification is required, and forwards the loaded spec to
the specified modifier. This allows for the same code to be
reused when performing more complex modifications.

Signed-off-by: Evan Lezar <elezar@nvidia.com>
2022-03-29 11:05:42 +02:00

86 lines
2.4 KiB
Go

/*
# Copyright (c) 2021, 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 main
import (
"os"
"os/exec"
"strings"
"github.com/NVIDIA/nvidia-container-toolkit/internal/oci"
"github.com/NVIDIA/nvidia-container-toolkit/internal/runtime"
"github.com/opencontainers/runtime-spec/specs-go"
log "github.com/sirupsen/logrus"
)
// newNvidiaContainerRuntime is a constructor for a standard runtime shim. This uses
// a ModifyingRuntimeWrapper to apply the required modifications before execing to the
// specified low-level runtime
func newNvidiaContainerRuntime(logger *log.Logger, lowlevelRuntime oci.Runtime, ociSpec oci.Spec) (oci.Runtime, error) {
modifier := addHookModifier{logger: logger}
r := runtime.NewModifyingRuntimeWrapper(
logger,
lowlevelRuntime,
ociSpec,
modifier,
)
return r, nil
}
// addHookModifier modifies an OCI spec inplace, inserting the nvidia-container-runtime-hook as a
// prestart hook. If the hook is already present, no modification is made.
type addHookModifier struct {
logger *log.Logger
}
// Modify applies the required modification to the incoming OCI spec, inserting the nvidia-container-runtime-hook
// as a prestart hook.
func (m addHookModifier) Modify(spec *specs.Spec) error {
path, err := exec.LookPath("nvidia-container-runtime-hook")
if err != nil {
path = hookDefaultFilePath
_, err = os.Stat(path)
if err != nil {
return err
}
}
m.logger.Printf("prestart hook path: %s\n", path)
args := []string{path}
if spec.Hooks == nil {
spec.Hooks = &specs.Hooks{}
} else if len(spec.Hooks.Prestart) != 0 {
for _, hook := range spec.Hooks.Prestart {
if !strings.Contains(hook.Path, "nvidia-container-runtime-hook") {
continue
}
m.logger.Println("existing nvidia prestart hook in OCI spec file")
return nil
}
}
spec.Hooks.Prestart = append(spec.Hooks.Prestart, specs.Hook{
Path: path,
Args: append(args, "prestart"),
})
return nil
}