Add CUDA image abstraction

This change adds a CUDA image abstraction that encapsulates
the queries performed on a container image (e.g. envvars) to
check certain CUDA properties.

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

internal/config/image/cuda_image.go

@@ -0,0 +1,143 @@
+/**
+# 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 image
+
+import (
+	"fmt"
+	"strconv"
+	"strings"
+
+	"github.com/opencontainers/runtime-spec/specs-go"
+	"golang.org/x/mod/semver"
+)
+
+const (
+	envCUDAVersion      = "CUDA_VERSION"
+	envNVRequirePrefix  = "NVIDIA_REQUIRE_"
+	envNVRequireCUDA    = envNVRequirePrefix + "CUDA"
+	envNVDisableRequire = "NVIDIA_DISABLE_REQUIRE"
+)
+
+// CUDA represents a CUDA image that can be used for GPU computing. This wraps
+// a map of environment variable to values that can be used to perform lookups
+// such as requirements.
+type CUDA map[string]string
+
+// NewCUDAImageFromSpec creates a CUDA image from the input OCI runtime spec.
+// The process environment is read (if present) to construc the CUDA Image.
+func NewCUDAImageFromSpec(spec *specs.Spec) (CUDA, error) {
+	if spec == nil || spec.Process == nil {
+		return NewCUDAImageFromEnv(nil)
+	}
+
+	return NewCUDAImageFromEnv(spec.Process.Env)
+}
+
+// NewCUDAImageFromEnv creates a CUDA image from the input environment. The environment
+// is a list of strings of the form ENVAR=VALUE.
+func NewCUDAImageFromEnv(env []string) (CUDA, error) {
+	c := make(CUDA)
+
+	for _, e := range env {
+		parts := strings.SplitN(e, "=", 2)
+		if len(parts) != 2 {
+			return nil, fmt.Errorf("invalid environment variable: %v", e)
+		}
+		c[parts[0]] = parts[1]
+	}
+
+	return c, nil
+}
+
+// IsLegacy returns whether the associated CUDA image is a "legacy" image. An
+// image is considered legacy if it has a CUDA_VERSION environment variable defined
+// and no NVIDIA_REQUIRE_CUDA environment variable defined.
+func (i CUDA) IsLegacy() bool {
+	legacyCudaVersion := i[envCUDAVersion]
+	cudaRequire := i[envNVRequireCUDA]
+	return len(legacyCudaVersion) > 0 && len(cudaRequire) == 0
+}
+
+// GetRequirements returns the requirements fomr all NVIDIA_REQUIRE_ environment
+// variables.
+func (i CUDA) GetRequirements() ([]string, error) {
+	// TODO: We need not process this if disable require is set, but this will be done
+	// in a single follow-up to ensure that the behavioural change is accurately captured.
+	// if i.HasDisableRequire() {
+	// 	return nil, nil
+	// }
+
+	// All variables with the "NVIDIA_REQUIRE_" prefix are passed to nvidia-container-cli
+	var requirements []string
+	for name, value := range i {
+		if strings.HasPrefix(name, envNVRequirePrefix) {
+			requirements = append(requirements, value)
+		}
+	}
+	if i.IsLegacy() {
+		v, err := i.legacyVersion()
+		if err != nil {
+			return nil, fmt.Errorf("failed to get version: %v", err)
+		}
+		cudaRequire := fmt.Sprintf("cuda>=%s", v)
+		requirements = append(requirements, cudaRequire)
+	}
+	return requirements, nil
+}
+
+// HasDisableRequire checks for the value of the NVIDIA_DISABLE_REQUIRE. If set
+// to a valid (true) boolean value this can be used to disable the requirement checks
+func (i CUDA) HasDisableRequire() bool {
+	if disable, exists := i[envNVDisableRequire]; exists {
+		// i.logger.Debugf("NVIDIA_DISABLE_REQUIRE=%v; skipping requirement checks", disable)
+		d, _ := strconv.ParseBool(disable)
+		return d
+	}
+
+	return false
+}
+
+func (i CUDA) legacyVersion() (string, error) {
+	majorMinor, err := parseMajorMinorVersion(i[envCUDAVersion])
+	if err != nil {
+		return "", fmt.Errorf("invalid CUDA version: %v", err)
+	}
+
+	return majorMinor, nil
+}
+
+func parseMajorMinorVersion(version string) (string, error) {
+	vVersion := "v" + strings.TrimPrefix(version, "v")
+
+	if !semver.IsValid(vVersion) {
+		return "", fmt.Errorf("invalid version string")
+	}
+
+	majorMinor := strings.TrimPrefix(semver.MajorMinor(vVersion), "v")
+	parts := strings.Split(majorMinor, ".")
+
+	var err error
+	_, err = strconv.ParseUint(parts[0], 10, 32)
+	if err != nil {
+		return "", fmt.Errorf("invalid major version")
+	}
+	_, err = strconv.ParseUint(parts[1], 10, 32)
+	if err != nil {
+		return "", fmt.Errorf("invalid minor version")
+	}
+	return majorMinor, nil
+}

internal/config/image/cuda_image_test.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 image
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/require"
+)
+
+func TestParseMajorMinorVersionValid(t *testing.T) {
+	var tests = []struct {
+		version  string
+		expected string
+	}{
+		{"0", "0.0"},
+		{"8", "8.0"},
+		{"7.5", "7.5"},
+		{"9.0.116", "9.0"},
+		{"4294967295.4294967295.4294967295", "4294967295.4294967295"},
+		{"v11.6", "11.6"},
+	}
+	for _, c := range tests {
+		t.Run(c.version, func(t *testing.T) {
+			version, err := parseMajorMinorVersion(c.version)
+
+			require.NoError(t, err)
+			require.Equal(t, c.expected, version)
+		})
+	}
+}
+
+func TestParseMajorMinorVersionInvalid(t *testing.T) {
+	var tests = []string{
+		"foo",
+		"foo.5.10",
+		"9.0.116.50",
+		"9.0.116foo",
+		"7.foo",
+		"9.0.bar",
+		"9.4294967296",
+		"9.0.116.",
+		"9..0",
+		"9.",
+		".5.10",
+		"-9",
+		"+9",
+		"-9.1.116",
+		"-9.-1.-116",
+	}
+	for _, c := range tests {
+		t.Run(c, func(t *testing.T) {
+			_, err := parseMajorMinorVersion(c)
+			require.Error(t, err)
+		})
+	}
+}