Implement runtime package for creating runtime CLI

Signed-off-by: Evan Lezar <elezar@nvidia.com>

internal/runtime/runtime_factory.go

@@ -0,0 +1,110 @@
+/*
+# Copyright (c) 2021-2022, 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 runtime
+
+import (
+	"fmt"
+
+	"github.com/NVIDIA/nvidia-container-toolkit/internal/config"
+	"github.com/NVIDIA/nvidia-container-toolkit/internal/info"
+	"github.com/NVIDIA/nvidia-container-toolkit/internal/modifier"
+	"github.com/NVIDIA/nvidia-container-toolkit/internal/oci"
+	"github.com/sirupsen/logrus"
+)
+
+// newNVIDIAContainerRuntime is a factory method that constructs a runtime based on the selected configuration and specified logger
+func newNVIDIAContainerRuntime(logger *logrus.Logger, cfg *config.Config, argv []string) (oci.Runtime, error) {
+	lowLevelRuntime, err := oci.NewLowLevelRuntime(logger, cfg.NVIDIAContainerRuntimeConfig.Runtimes)
+	if err != nil {
+		return nil, fmt.Errorf("error constructing low-level runtime: %v", err)
+	}
+
+	if !oci.HasCreateSubcommand(argv) {
+		logger.Debugf("Skipping modifier for non-create subcommand")
+		return lowLevelRuntime, nil
+	}
+
+	ociSpec, err := oci.NewSpec(logger, argv)
+	if err != nil {
+		return nil, fmt.Errorf("error constructing OCI specification: %v", err)
+	}
+
+	specModifier, err := newSpecModifier(logger, cfg, ociSpec, argv)
+	if err != nil {
+		return nil, fmt.Errorf("failed to construct OCI spec modifier: %v", err)
+	}
+
+	// Create the wrapping runtime with the specified modifier
+	r := oci.NewModifyingRuntimeWrapper(
+		logger,
+		lowLevelRuntime,
+		ociSpec,
+		specModifier,
+	)
+
+	return r, nil
+}
+
+// newSpecModifier is a factory method that creates constructs an OCI spec modifer based on the provided config.
+func newSpecModifier(logger *logrus.Logger, cfg *config.Config, ociSpec oci.Spec, argv []string) (oci.SpecModifier, error) {
+	modeModifier, err := newModeModifier(logger, cfg, ociSpec, argv)
+	if err != nil {
+		return nil, err
+	}
+
+	graphicsModifier, err := modifier.NewGraphicsModifier(logger, cfg, ociSpec)
+	if err != nil {
+		return nil, err
+	}
+
+	gdsModifier, err := modifier.NewGDSModifier(logger, cfg, ociSpec)
+	if err != nil {
+		return nil, err
+	}
+
+	mofedModifier, err := modifier.NewMOFEDModifier(logger, cfg, ociSpec)
+	if err != nil {
+		return nil, err
+	}
+
+	tegraModifier, err := modifier.NewTegraPlatformFiles(logger)
+	if err != nil {
+		return nil, err
+	}
+
+	modifiers := modifier.Merge(
+		modeModifier,
+		graphicsModifier,
+		gdsModifier,
+		mofedModifier,
+		tegraModifier,
+	)
+	return modifiers, nil
+}
+
+func newModeModifier(logger *logrus.Logger, cfg *config.Config, ociSpec oci.Spec, argv []string) (oci.SpecModifier, error) {
+	switch info.ResolveAutoMode(logger, cfg.NVIDIAContainerRuntimeConfig.Mode) {
+	case "legacy":
+		return modifier.NewStableRuntimeModifier(logger), nil
+	case "csv":
+		return modifier.NewCSVModifier(logger, cfg, ociSpec)
+	case "cdi":
+		return modifier.NewCDIModifier(logger, cfg, ociSpec)
+	}
+
+	return nil, fmt.Errorf("invalid runtime mode: %v", cfg.NVIDIAContainerRuntimeConfig.Mode)
+}