Refactor info API

This change adds a PropertyExtractor interface to encapsulate functions
that query a system for certain capabilities.

The IsTegraSystem has been renamed to HasTegraFiles function and marked
as Deprecated.

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

pkg/nvlib/info/api.go

@@ -0,0 +1,34 @@
+/**
+# Copyright 2024 NVIDIA CORPORATION
+#
+# 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 info
+
+// Interface provides the API to the info package.
+type Interface interface {
+	PropertyExtractor
+}
+
+// PropertyExtractor provides a set of functions to query capabilities of the
+// system.
+//
+//go:generate moq -rm -out property-extractor_mock.go . PropertyExtractor
+type PropertyExtractor interface {
+	HasDXCore() (bool, string)
+	HasNvml() (bool, string)
+	HasTegraFiles() (bool, string)
+	// Deprecated: Use HasTegraFiles instead.
+	IsTegraSystem() (bool, string)
+}

pkg/nvlib/info/builder.go

@@ -0,0 +1,35 @@
+/**
+# Copyright 2024 NVIDIA CORPORATION
+#
+# 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 info
+
+type options struct {
+	root root
+}
+
+// New creates a new instance of the 'info' Interface.
+func New(opts ...Option) Interface {
+	o := &options{}
+	for _, opt := range opts {
+		opt(o)
+	}
+	if o.root == "" {
+		o.root = "/"
+	}
+	return &propertyExtractor{
+		root: o.root,
+	}
+}

pkg/nvlib/info/options.go

@@ -17,23 +17,11 @@
 package info
 
 // Option defines a function for passing options to the New() call.
-type Option func(*infolib)
-
-// New creates a new instance of the 'info' interface.
-func New(opts ...Option) Interface {
-	i := &infolib{}
-	for _, opt := range opts {
-		opt(i)
-	}
-	if i.root == "" {
-		i.root = "/"
-	}
-	return i
-}
+type Option func(*options)
 
 // WithRoot provides a Option to set the root of the 'info' interface.
-func WithRoot(root string) Option {
-	return func(i *infolib) {
-		i.root = root
+func WithRoot(r string) Option {
+	return func(i *options) {
+		i.root = root(r)
 	}
 }

pkg/nvlib/info/property-extractor.go

@@ -19,31 +19,21 @@ package info
 import (
 	"fmt"
 	"os"
-	"path/filepath"
 	"strings"
-
-	"github.com/NVIDIA/go-nvml/pkg/dl"
 )
 
-// Interface provides the API to the info package.
-type Interface interface {
-	HasDXCore() (bool, string)
-	HasNvml() (bool, string)
-	IsTegraSystem() (bool, string)
+type propertyExtractor struct {
+	root root
 }
 
-type infolib struct {
-	root string
-}
-
-var _ Interface = &infolib{}
+var _ Interface = &propertyExtractor{}
 
 // HasDXCore returns true if DXCore is detected on the system.
-func (i *infolib) HasDXCore() (bool, string) {
+func (i *propertyExtractor) HasDXCore() (bool, string) {
 	const (
 		libraryName = "libdxcore.so"
 	)
-	if err := assertHasLibrary(libraryName); err != nil {
+	if err := i.root.assertHasLibrary(libraryName); err != nil {
 		return false, fmt.Sprintf("could not load DXCore library: %v", err)
 	}
 
@@ -51,11 +41,11 @@ func (i *infolib) HasDXCore() (bool, string) {
 }
 
 // HasNvml returns true if NVML is detected on the system.
-func (i *infolib) HasNvml() (bool, string) {
+func (i *propertyExtractor) HasNvml() (bool, string) {
 	const (
 		libraryName = "libnvidia-ml.so.1"
 	)
-	if err := assertHasLibrary(libraryName); err != nil {
+	if err := i.root.assertHasLibrary(libraryName); err != nil {
 		return false, fmt.Sprintf("could not load NVML library: %v", err)
 	}
 
@@ -63,9 +53,15 @@ func (i *infolib) HasNvml() (bool, string) {
 }
 
 // IsTegraSystem returns true if the system is detected as a Tegra-based system.
-func (i *infolib) IsTegraSystem() (bool, string) {
-	tegraReleaseFile := filepath.Join(i.root, "/etc/nv_tegra_release")
-	tegraFamilyFile := filepath.Join(i.root, "/sys/devices/soc0/family")
+// Deprecated: Use HasTegraFiles instead.
+func (i *propertyExtractor) IsTegraSystem() (bool, string) {
+	return i.HasTegraFiles()
+}
+
+// HasTegraFiles returns true if tegra-based files are detected on the system.
+func (i *propertyExtractor) HasTegraFiles() (bool, string) {
+	tegraReleaseFile := i.root.join("/etc/nv_tegra_release")
+	tegraFamilyFile := i.root.join("/sys/devices/soc0/family")
 
 	if info, err := os.Stat(tegraReleaseFile); err == nil && !info.IsDir() {
 		return true, fmt.Sprintf("%v found", tegraReleaseFile)
@@ -86,17 +82,3 @@ func (i *infolib) IsTegraSystem() (bool, string) {
 
 	return false, fmt.Sprintf("%v has no 'tegra' prefix", tegraFamilyFile)
 }
-
-// assertHasLibrary returns an error if the specified library cannot be loaded.
-func assertHasLibrary(libraryName string) error {
-	const (
-		libraryLoadFlags = dl.RTLD_LAZY
-	)
-	lib := dl.New(libraryName, libraryLoadFlags)
-	if err := lib.Open(); err != nil {
-		return err
-	}
-	defer lib.Close()
-
-	return nil
-}

pkg/nvlib/info/property-extractor_mock.go

@@ -0,0 +1,178 @@
+// Code generated by moq; DO NOT EDIT.
+// github.com/matryer/moq
+
+package info
+
+import (
+	"sync"
+)
+
+// Ensure, that PropertyExtractorMock does implement PropertyExtractor.
+// If this is not the case, regenerate this file with moq.
+var _ PropertyExtractor = &PropertyExtractorMock{}
+
+// PropertyExtractorMock is a mock implementation of PropertyExtractor.
+//
+//	func TestSomethingThatUsesPropertyExtractor(t *testing.T) {
+//
+//		// make and configure a mocked PropertyExtractor
+//		mockedPropertyExtractor := &PropertyExtractorMock{
+//			HasDXCoreFunc: func() (bool, string) {
+//				panic("mock out the HasDXCore method")
+//			},
+//			HasNvmlFunc: func() (bool, string) {
+//				panic("mock out the HasNvml method")
+//			},
+//			HasTegraFilesFunc: func() (bool, string) {
+//				panic("mock out the HasTegraFiles method")
+//			},
+//			IsTegraSystemFunc: func() (bool, string) {
+//				panic("mock out the IsTegraSystem method")
+//			},
+//		}
+//
+//		// use mockedPropertyExtractor in code that requires PropertyExtractor
+//		// and then make assertions.
+//
+//	}
+type PropertyExtractorMock struct {
+	// HasDXCoreFunc mocks the HasDXCore method.
+	HasDXCoreFunc func() (bool, string)
+
+	// HasNvmlFunc mocks the HasNvml method.
+	HasNvmlFunc func() (bool, string)
+
+	// HasTegraFilesFunc mocks the HasTegraFiles method.
+	HasTegraFilesFunc func() (bool, string)
+
+	// IsTegraSystemFunc mocks the IsTegraSystem method.
+	IsTegraSystemFunc func() (bool, string)
+
+	// calls tracks calls to the methods.
+	calls struct {
+		// HasDXCore holds details about calls to the HasDXCore method.
+		HasDXCore []struct {
+		}
+		// HasNvml holds details about calls to the HasNvml method.
+		HasNvml []struct {
+		}
+		// HasTegraFiles holds details about calls to the HasTegraFiles method.
+		HasTegraFiles []struct {
+		}
+		// IsTegraSystem holds details about calls to the IsTegraSystem method.
+		IsTegraSystem []struct {
+		}
+	}
+	lockHasDXCore     sync.RWMutex
+	lockHasNvml       sync.RWMutex
+	lockHasTegraFiles sync.RWMutex
+	lockIsTegraSystem sync.RWMutex
+}
+
+// HasDXCore calls HasDXCoreFunc.
+func (mock *PropertyExtractorMock) HasDXCore() (bool, string) {
+	if mock.HasDXCoreFunc == nil {
+		panic("PropertyExtractorMock.HasDXCoreFunc: method is nil but PropertyExtractor.HasDXCore was just called")
+	}
+	callInfo := struct {
+	}{}
+	mock.lockHasDXCore.Lock()
+	mock.calls.HasDXCore = append(mock.calls.HasDXCore, callInfo)
+	mock.lockHasDXCore.Unlock()
+	return mock.HasDXCoreFunc()
+}
+
+// HasDXCoreCalls gets all the calls that were made to HasDXCore.
+// Check the length with:
+//
+//	len(mockedPropertyExtractor.HasDXCoreCalls())
+func (mock *PropertyExtractorMock) HasDXCoreCalls() []struct {
+} {
+	var calls []struct {
+	}
+	mock.lockHasDXCore.RLock()
+	calls = mock.calls.HasDXCore
+	mock.lockHasDXCore.RUnlock()
+	return calls
+}
+
+// HasNvml calls HasNvmlFunc.
+func (mock *PropertyExtractorMock) HasNvml() (bool, string) {
+	if mock.HasNvmlFunc == nil {
+		panic("PropertyExtractorMock.HasNvmlFunc: method is nil but PropertyExtractor.HasNvml was just called")
+	}
+	callInfo := struct {
+	}{}
+	mock.lockHasNvml.Lock()
+	mock.calls.HasNvml = append(mock.calls.HasNvml, callInfo)
+	mock.lockHasNvml.Unlock()
+	return mock.HasNvmlFunc()
+}
+
+// HasNvmlCalls gets all the calls that were made to HasNvml.
+// Check the length with:
+//
+//	len(mockedPropertyExtractor.HasNvmlCalls())
+func (mock *PropertyExtractorMock) HasNvmlCalls() []struct {
+} {
+	var calls []struct {
+	}
+	mock.lockHasNvml.RLock()
+	calls = mock.calls.HasNvml
+	mock.lockHasNvml.RUnlock()
+	return calls
+}
+
+// HasTegraFiles calls HasTegraFilesFunc.
+func (mock *PropertyExtractorMock) HasTegraFiles() (bool, string) {
+	if mock.HasTegraFilesFunc == nil {
+		panic("PropertyExtractorMock.HasTegraFilesFunc: method is nil but PropertyExtractor.HasTegraFiles was just called")
+	}
+	callInfo := struct {
+	}{}
+	mock.lockHasTegraFiles.Lock()
+	mock.calls.HasTegraFiles = append(mock.calls.HasTegraFiles, callInfo)
+	mock.lockHasTegraFiles.Unlock()
+	return mock.HasTegraFilesFunc()
+}
+
+// HasTegraFilesCalls gets all the calls that were made to HasTegraFiles.
+// Check the length with:
+//
+//	len(mockedPropertyExtractor.HasTegraFilesCalls())
+func (mock *PropertyExtractorMock) HasTegraFilesCalls() []struct {
+} {
+	var calls []struct {
+	}
+	mock.lockHasTegraFiles.RLock()
+	calls = mock.calls.HasTegraFiles
+	mock.lockHasTegraFiles.RUnlock()
+	return calls
+}
+
+// IsTegraSystem calls IsTegraSystemFunc.
+func (mock *PropertyExtractorMock) IsTegraSystem() (bool, string) {
+	if mock.IsTegraSystemFunc == nil {
+		panic("PropertyExtractorMock.IsTegraSystemFunc: method is nil but PropertyExtractor.IsTegraSystem was just called")
+	}
+	callInfo := struct {
+	}{}
+	mock.lockIsTegraSystem.Lock()
+	mock.calls.IsTegraSystem = append(mock.calls.IsTegraSystem, callInfo)
+	mock.lockIsTegraSystem.Unlock()
+	return mock.IsTegraSystemFunc()
+}
+
+// IsTegraSystemCalls gets all the calls that were made to IsTegraSystem.
+// Check the length with:
+//
+//	len(mockedPropertyExtractor.IsTegraSystemCalls())
+func (mock *PropertyExtractorMock) IsTegraSystemCalls() []struct {
+} {
+	var calls []struct {
+	}
+	mock.lockIsTegraSystem.RLock()
+	calls = mock.calls.IsTegraSystem
+	mock.lockIsTegraSystem.RUnlock()
+	return calls
+}

pkg/nvlib/info/root.go

@@ -0,0 +1,86 @@
+/**
+# Copyright 2024 NVIDIA CORPORATION
+#
+# 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 info
+
+import (
+	"fmt"
+	"path/filepath"
+
+	"github.com/NVIDIA/go-nvml/pkg/dl"
+)
+
+// root represents a directory on the filesystem relative to which libraries
+// such as the NVIDIA driver libraries can be found.
+type root string
+
+func (r root) join(parts ...string) string {
+	return filepath.Join(append([]string{string(r)}, parts...)...)
+}
+
+// assertHasLibrary returns an error if the specified library cannot be loaded.
+func (r root) assertHasLibrary(libraryName string) error {
+	const (
+		libraryLoadFlags = dl.RTLD_LAZY
+	)
+	lib := dl.New(r.tryResolveLibrary(libraryName), libraryLoadFlags)
+	if err := lib.Open(); err != nil {
+		return err
+	}
+	defer lib.Close()
+
+	return nil
+}
+
+// tryResolveLibrary attempts to locate the specified library in the root.
+// If the root is not specified, is "/", or the library cannot be found in the
+// set of predefined paths, the input is returned as is.
+func (r root) tryResolveLibrary(libraryName string) string {
+	if r == "" || r == "/" {
+		return libraryName
+	}
+
+	librarySearchPaths := []string{
+		"/usr/lib64",
+		"/usr/lib/x86_64-linux-gnu",
+		"/usr/lib/aarch64-linux-gnu",
+		"/lib64",
+		"/lib/x86_64-linux-gnu",
+		"/lib/aarch64-linux-gnu",
+	}
+
+	for _, d := range librarySearchPaths {
+		l := r.join(d, libraryName)
+		resolved, err := resolveLink(l)
+		if err != nil {
+			continue
+		}
+		return resolved
+	}
+
+	return libraryName
+}
+
+// resolveLink finds the target of a symlink or the file itself in the
+// case of a regular file.
+// This is equivalent to running `readlink -f ${l}`.
+func resolveLink(l string) (string, error) {
+	resolved, err := filepath.EvalSymlinks(l)
+	if err != nil {
+		return "", fmt.Errorf("error resolving link '%v': %w", l, err)
+	}
+	return resolved, nil
+}