nvidia-container-toolkit/internal/runtime/runtime_modifier.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

82 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 runtime
import (
"fmt"
"github.com/NVIDIA/nvidia-container-toolkit/internal/oci"
log "github.com/sirupsen/logrus"
)
type modifyingRuntimeWrapper struct {
logger *log.Logger
runtime oci.Runtime
ociSpec oci.Spec
modifier oci.SpecModifier
}
var _ oci.Runtime = (*modifyingRuntimeWrapper)(nil)
// NewModifyingRuntimeWrapper creates a runtime wrapper that applies the specified modifier to the OCI specification
// before invoking the wrapped runtime.
func NewModifyingRuntimeWrapper(logger *log.Logger, runtime oci.Runtime, spec oci.Spec, modifier oci.SpecModifier) oci.Runtime {
rt := modifyingRuntimeWrapper{
logger: logger,
runtime: runtime,
ociSpec: spec,
modifier: modifier,
}
return &rt
}
// Exec checks whether a modification of the OCI specification is required and modifies it accordingly before exec-ing
// into the wrapped runtime.
func (r *modifyingRuntimeWrapper) Exec(args []string) error {
if oci.HasCreateSubcommand(args) {
err := r.modify()
if err != nil {
return fmt.Errorf("could not apply required modification to OCI specification: %v", err)
}
r.logger.Infof("Applied required modification to OCI specification")
} else {
r.logger.Infof("No modification of OCI specification required")
}
r.logger.Infof("Forwarding command to runtime")
return r.runtime.Exec(args)
}
// modify loads, modifies, and flushes the OCI specification using the defined Modifier
func (r *modifyingRuntimeWrapper) modify() error {
err := r.ociSpec.Load()
if err != nil {
return fmt.Errorf("error loading OCI specification for modification: %v", err)
}
err = r.ociSpec.Modify(r.modifier)
if err != nil {
return fmt.Errorf("error modifying OCI spec: %v", err)
}
err = r.ociSpec.Flush()
if err != nil {
return fmt.Errorf("error writing modified OCI specification: %v", err)
}
return nil
}