pkg/cdi: add functions for generating Spec names and removing Spec files.

pkg/cdi/cache.go

@@ -17,11 +17,15 @@
 package cdi
 
 import (
+	"io/fs"
+	"os"
 	"path/filepath"
 	"sort"
 	"strings"
 	"sync"
 
+	stderr "errors"
+
 	cdi "github.com/container-orchestrated-devices/container-device-interface/specs-go"
 	"github.com/fsnotify/fsnotify"
 	"github.com/hashicorp/go-multierror"
@@ -255,11 +259,22 @@ func (c *Cache) InjectDevices(ociSpec *oci.Spec, devices ...string) ([]string, e
 	return nil, nil
 }
 
-// WriteSpec writes a Spec file with the given content. Priority is used
-// as an index into the list of Spec directories to pick a directory for
-// the file, adjusting for any under- or overflows. If name has a "json"
-// or "yaml" extension it choses the encoding. Otherwise JSON encoding
-// is used with a "json" extension.
+// highestPrioritySpecDir returns the Spec directory with highest priority
+// and its priority.
+func (c *Cache) highestPrioritySpecDir() (string, int) {
+	if len(c.specDirs) == 0 {
+		return "", -1
+	}
+
+	prio := len(c.specDirs) - 1
+	dir := c.specDirs[prio]
+
+	return dir, prio
+}
+
+// WriteSpec writes a Spec file with the given content into the highest
+// priority Spec directory. If name has a "json" or "yaml" extension it
+// choses the encoding. Otherwise the default YAML encoding is used.
 func (c *Cache) WriteSpec(raw *cdi.Spec, name string) error {
 	var (
 		specDir string
@@ -269,23 +284,51 @@ func (c *Cache) WriteSpec(raw *cdi.Spec, name string) error {
 		err     error
 	)
 
-	if len(c.specDirs) == 0 {
+	specDir, prio = c.highestPrioritySpecDir()
+	if specDir == "" {
 		return errors.New("no Spec directories to write to")
 	}
 
-	prio = len(c.specDirs) - 1
-	specDir = c.specDirs[prio]
 	path = filepath.Join(specDir, name)
 	if ext := filepath.Ext(path); ext != ".json" && ext != ".yaml" {
-		path += ".json"
+		path += defaultSpecExt
 	}
 
-	spec, err = NewSpec(raw, path, prio)
+	spec, err = newSpec(raw, path, prio)
 	if err != nil {
 		return err
 	}
 
-	return spec.Write(true)
+	return spec.write(true)
+}
+
+// RemoveSpec removes a Spec with the given name from the highest
+// priority Spec directory. This function can be used to remove a
+// Spec previously written by WriteSpec(). If the file exists and
+// its removal fails RemoveSpec returns an error.
+func (c *Cache) RemoveSpec(name string) error {
+	var (
+		specDir string
+		path    string
+		err     error
+	)
+
+	specDir, _ = c.highestPrioritySpecDir()
+	if specDir == "" {
+		return errors.New("no Spec directories to remove from")
+	}
+
+	path = filepath.Join(specDir, name)
+	if ext := filepath.Ext(path); ext != ".json" && ext != ".yaml" {
+		path += defaultSpecExt
+	}
+
+	err = os.Remove(path)
+	if err != nil && stderr.Is(err, fs.ErrNotExist) {
+		err = nil
+	}
+
+	return err
 }
 
 // GetDevice returns the cached device for the given qualified name.

pkg/cdi/cache_test.go

@@ -17,8 +17,10 @@
 package cdi
 
 import (
+	"fmt"
 	"os"
 	"path/filepath"
+	"strconv"
 	"strings"
 	"sync"
 	"testing"
@@ -29,6 +31,7 @@ import (
 	oci "github.com/opencontainers/runtime-spec/specs-go"
 	"github.com/pkg/errors"
 	"github.com/stretchr/testify/require"
+	"sigs.k8s.io/yaml"
 )
 
 func TestNewCache(t *testing.T) {
@@ -1633,6 +1636,215 @@ containerEdits:
 	}
 }
 
+func TestCacheTransientSpecs(t *testing.T) {
+	type testCase struct {
+		name         string
+		specs        []string
+		invalid      map[int]bool
+		expected     [][]string
+		numSpecFiles []int
+	}
+	for _, tc := range []*testCase{
+		{
+			name: "invalid spec",
+			specs: []string{
+				`
+cdiVersion: "` + cdi.CurrentVersion + `"
+kind:       "vendor.comdevice"
+devices:
+  - name: "dev1"
+    containerEdits:
+      deviceNodes:
+      - path: "/dev/vendor1-dev1"
+        type: b
+        major: 10
+        minor: 1`,
+			},
+			invalid: map[int]bool{
+				0: true,
+			},
+		},
+		{
+			name: "add/remove one valid spec",
+			specs: []string{
+				`
+cdiVersion: "` + cdi.CurrentVersion + `"
+kind:       "vendor.com/device"
+devices:
+  - name: "dev1"
+    containerEdits:
+      deviceNodes:
+      - path: "/dev/vendor-dev1"
+        type: b
+        major: 10
+        minor: 1
+`,
+				"-0",
+			},
+			expected: [][]string{
+				[]string{
+					"vendor.com/device=dev1",
+				},
+				nil,
+			},
+			numSpecFiles: []int{
+				1,
+				0,
+			},
+		},
+		{
+			name: "add/remove multiple valid specs",
+			specs: []string{
+				`
+cdiVersion: "` + cdi.CurrentVersion + `"
+kind:       "vendor.com/device"
+devices:
+  - name: "dev1"
+    containerEdits:
+      deviceNodes:
+      - path: "/dev/vendor-dev1"
+        type: b
+        major: 10
+        minor: 1
+`,
+				`
+cdiVersion: "` + cdi.CurrentVersion + `"
+kind:       "vendor.com/device"
+devices:
+  - name: "dev2"
+    containerEdits:
+      deviceNodes:
+      - path: "/dev/vendor-dev2"
+        type: b
+        major: 10
+        minor: 2
+`,
+				`
+cdiVersion: "` + cdi.CurrentVersion + `"
+kind:       "vendor.com/device"
+devices:
+  - name: "dev3"
+    containerEdits:
+      deviceNodes:
+      - path: "/dev/vendor-dev3"
+        type: b
+        major: 10
+        minor: 3
+  - name: "dev4"
+    containerEdits:
+      deviceNodes:
+      - path: "/dev/vendor-dev4"
+        type: b
+        major: 10
+        minor: 4
+`,
+				"-0",
+				"-1",
+				"-2",
+			},
+			expected: [][]string{
+				[]string{
+					"vendor.com/device=dev1",
+				},
+				[]string{
+					"vendor.com/device=dev1",
+					"vendor.com/device=dev2",
+				},
+				[]string{
+					"vendor.com/device=dev1",
+					"vendor.com/device=dev2",
+					"vendor.com/device=dev3",
+					"vendor.com/device=dev4",
+				},
+				[]string{
+					"vendor.com/device=dev2",
+					"vendor.com/device=dev3",
+					"vendor.com/device=dev4",
+				},
+				[]string{
+					"vendor.com/device=dev3",
+					"vendor.com/device=dev4",
+				},
+				nil,
+			},
+			numSpecFiles: []int{
+				1,
+				2,
+				3,
+				2,
+				1,
+				0,
+			},
+		},
+	} {
+		t.Run(tc.name, func(t *testing.T) {
+			var (
+				dir       string
+				err       error
+				cache     *Cache
+				specFiles []os.DirEntry
+				specs     = map[int]string{}
+			)
+
+			dir, err = createSpecDirs(t, nil, nil)
+			require.NoError(t, err)
+			cache, err = NewCache(
+				WithSpecDirs(
+					filepath.Join(dir, "etc"),
+					filepath.Join(dir, "run"),
+				),
+				WithAutoRefresh(false),
+			)
+
+			require.NoError(t, err)
+			require.NotNil(t, cache)
+
+			for idx, data := range tc.specs {
+				var (
+					transientID string
+					raw         *cdi.Spec
+					delIdx      int
+					err         error
+				)
+
+				if data[0] == '-' {
+					delIdx, err = strconv.Atoi(string(data[1:]))
+					require.NoError(t, err)
+
+					err = cache.RemoveSpec(specs[delIdx])
+					require.NoError(t, err)
+				} else {
+					err = yaml.Unmarshal([]byte(data), &raw)
+					require.NoError(t, err)
+
+					transientID = fmt.Sprintf("id%d", idx)
+					specs[idx], err = GenerateNameForTransientSpec(raw, transientID)
+					if tc.invalid[idx] {
+						require.NotNil(t, err)
+						continue
+					}
+					require.NoError(t, err)
+
+					err = cache.WriteSpec(raw, specs[idx])
+					require.NoError(t, err)
+				}
+
+				err = cache.Refresh()
+				require.NoError(t, err)
+
+				devices := cache.ListDevices()
+				require.Equal(t, tc.expected[idx], devices)
+
+				specFiles, err = os.ReadDir(
+					filepath.Join(dir, "run"),
+				)
+				require.NoError(t, err)
+				require.Equal(t, tc.numSpecFiles[idx], len(specFiles))
+			}
+		})
+	}
+}
+
 // Create and populate automatically cleaned up spec directories.
 func createSpecDirs(t *testing.T, etc, run map[string]string) (string, error) {
 	return mkTestDir(t, map[string]map[string]string{