Merge pull request #64 from klihub/devel/spec-write-api

pkg/cdi: add functions for writing Spec files.

Author: elezar

pkg/cdi/cache.go

@@ -22,6 +22,7 @@ import (
 	"strings"
 	"sync"
 
+	cdi "github.com/container-orchestrated-devices/container-device-interface/specs-go"
 	"github.com/fsnotify/fsnotify"
 	"github.com/hashicorp/go-multierror"
 	oci "github.com/opencontainers/runtime-spec/specs-go"
@@ -254,6 +255,39 @@ 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.
+func (c *Cache) WriteSpec(raw *cdi.Spec, name string) error {
+	var (
+		specDir string
+		path    string
+		prio    int
+		spec    *Spec
+		err     error
+	)
+
+	if len(c.specDirs) == 0 {
+		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"
+	}
+
+	spec, err = NewSpec(raw, path, prio)
+	if err != nil {
+		return err
+	}
+
+	return spec.Write(true)
+}
+
 // GetDevice returns the cached device for the given qualified name.
 func (c *Cache) GetDevice(device string) *Device {
 	c.Lock()

pkg/cdi/cache_test.go

@@ -25,6 +25,8 @@ import (
 	"testing"
 	"time"
 
+	"github.com/container-orchestrated-devices/container-device-interface/pkg/cdi/validate"
+	cdi "github.com/container-orchestrated-devices/container-device-interface/specs-go"
 	oci "github.com/opencontainers/runtime-spec/specs-go"
 	"github.com/pkg/errors"
 	"github.com/stretchr/testify/require"
@@ -1420,6 +1422,218 @@ devices:
 	}
 }
 
+func TestCacheWriteSpec(t *testing.T) {
+	type testCase struct {
+		name    string
+		etc     map[string]string
+		invalid map[string]bool
+	}
+	for _, tc := range []*testCase{
+		{
+			name: "one spec file",
+			etc: map[string]string{
+				"vendor1.yaml": `
+cdiVersion: "0.3.0"
+kind:       "vendor1.com/device"
+devices:
+  - name: "dev1"
+    containerEdits:
+      deviceNodes:
+      - path: "/dev/vendor1-dev1"
+        type: b
+        major: 10
+        minor: 1
+`,
+			},
+		},
+		{
+			name: "multiple spec files",
+			etc: map[string]string{
+				"vendor1.yaml": `
+cdiVersion: "0.3.0"
+kind:       "vendor1.com/device"
+devices:
+  - name: "dev1"
+    containerEdits:
+      deviceNodes:
+      - path: "/dev/vendor1-dev1"
+        type: b
+        major: 10
+        minor: 1
+  - name: "dev2"
+    containerEdits:
+      deviceNodes:
+      - path: "/dev/vendor1-dev2"
+        type: b
+        major: 10
+        minor: 2
+`,
+				"vendor2.yaml": `
+cdiVersion: "0.3.0"
+kind:       "vendor2.com/device"
+devices:
+  - name: "dev1"
+    containerEdits:
+      deviceNodes:
+      - path: "/dev/vendor2-dev1"
+        type: b
+        major: 10
+        minor: 1
+`,
+				"vendor3.yaml": `
+cdiVersion: "0.3.0"
+kind:       "vendor3.com/device"
+devices:
+  - name: "dev1"
+    containerEdits:
+      deviceNodes:
+      - path: "/dev/vendor3-dev1"
+        type: b
+        major: 10
+        minor: 1
+`,
+			},
+		},
+
+		{
+			name: "multiple spec files/data, some invalid",
+			etc: map[string]string{
+				"vendor1.yaml": `
+cdiVersion: "0.3.0"
+kind:       "vendor1.comdevice"
+devices:
+  - name: "dev1"
+    containerEdits:
+      deviceNodes:
+      - path: "/dev/vendor1-dev1"
+        type: b
+        major: 10
+        minor: 1
+  - name: "dev2"
+    containerEdits:
+      deviceNodes:
+      - path: "/dev/vendor1-dev2"
+        type: b
+        major: 10
+        minor: 2
+`,
+				"vendor2.yaml": `
+cdiVersion: "0.3.0"
+kind:       "vendor2.com/device"
+devices:
+  - name: "dev1"
+    containerEdits:
+      deviceNodes:
+      - path: "/dev/vendor2-dev1"
+        type: b
+        major: 10
+        minor: 1
+`,
+				"vendor3.yaml": `
+cdiVersion: "0.3.0"
+kind:       "vendor3.com/device"
+containerEdits:
+  deviceNodes:
+  - path: "/dev/vendor3-dev1"
+    type: b
+    major: 10
+    minor: 1
+`,
+			},
+			invalid: map[string]bool{
+				"vendor1.yaml": true,
+				"vendor3.yaml": true,
+			},
+		},
+	} {
+		t.Run(tc.name, func(t *testing.T) {
+			var (
+				dir   string
+				etc   map[string]string
+				raw   *cdi.Spec
+				err   error
+				cache *Cache
+				other *Cache
+			)
+
+			SetSpecValidator(validate.WithNamedSchema("builtin"))
+
+			if len(tc.invalid) != 0 {
+				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)
+
+				etc = map[string]string{}
+				for name, data := range tc.etc {
+					raw, err = ParseSpec([]byte(data))
+					require.NoError(t, err)
+					require.NotNil(t, raw)
+
+					err = cache.WriteSpec(raw, name)
+
+					if tc.invalid[name] {
+						require.Error(t, err)
+					} else {
+						require.NoError(t, err)
+						etc[name] = data
+					}
+				}
+			} else {
+				etc = tc.etc
+			}
+
+			dir, err = createSpecDirs(t, etc, nil)
+			require.NoError(t, err)
+
+			cache, err = NewCache(
+				WithSpecDirs(
+					filepath.Join(dir, "etc"),
+				),
+			)
+			require.NoError(t, err)
+			require.NotNil(t, cache)
+
+			other, err = NewCache(
+				WithSpecDirs(
+					filepath.Join(dir, "run"),
+				),
+				WithAutoRefresh(false),
+			)
+			require.NoError(t, err)
+			require.NotNil(t, other)
+
+			cSpecs := map[string]*cdi.Spec{}
+			for _, vendor := range cache.ListVendors() {
+				for _, spec := range cache.GetVendorSpecs(vendor) {
+					name := filepath.Base(spec.GetPath())
+					cSpecs[name] = spec.Spec
+					err = other.WriteSpec(spec.Spec, name)
+					require.NoError(t, err)
+				}
+			}
+
+			err = other.Refresh()
+			require.NoError(t, err)
+
+			for _, vendor := range other.ListVendors() {
+				for _, spec := range other.GetVendorSpecs(vendor) {
+					name := filepath.Base(spec.GetPath())
+					require.Equal(t, spec.Spec, cSpecs[name])
+				}
+			}
+		})
+	}
+}
+
 // 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{

pkg/cdi/registry.go

@@ -19,6 +19,7 @@ package cdi
 import (
 	"sync"
 
+	cdi "github.com/container-orchestrated-devices/container-device-interface/specs-go"
 	oci "github.com/opencontainers/runtime-spec/specs-go"
 )
 
@@ -97,11 +98,15 @@ type RegistryDeviceDB interface {
 //
 // GetSpecErrors returns any errors for the Spec encountered during
 // the last cache refresh.
+//
+// WriteSpec writes the Spec with the given content and name to the
+// last Spec directory.
 type RegistrySpecDB interface {
 	ListVendors() []string
 	ListClasses() []string
 	GetVendorSpecs(vendor string) []*Spec
 	GetSpecErrors(*Spec) []error
+	WriteSpec(raw *cdi.Spec, name string) error
 }
 
 type registry struct {

pkg/cdi/spec.go

@@ -17,6 +17,7 @@
 package cdi
 
 import (
+	"encoding/json"
 	"io/ioutil"
 	"os"
 	"path/filepath"
@@ -68,7 +69,7 @@ func ReadSpec(path string, priority int) (*Spec, error) {
 		return nil, errors.Wrapf(err, "failed to read CDI Spec %q", path)
 	}
 
-	raw, err := parseSpec(data)
+	raw, err := ParseSpec(data)
 	if err != nil {
 		return nil, errors.Wrapf(err, "failed to parse CDI Spec %q", path)
 	}
@@ -109,6 +110,56 @@ func NewSpec(raw *cdi.Spec, path string, priority int) (*Spec, error) {
 	return spec, nil
 }
 
+// Write the CDI Spec to the file associated with it during instantiation
+// by NewSpec() or ReadSpec().
+func (s *Spec) Write(overwrite bool) error {
+	var (
+		data []byte
+		dir  string
+		tmp  *os.File
+		err  error
+	)
+
+	err = validateSpec(s.Spec)
+	if err != nil {
+		return err
+	}
+
+	if filepath.Ext(s.path) == ".yaml" {
+		data, err = yaml.Marshal(s.Spec)
+	} else {
+		data, err = json.Marshal(s.Spec)
+	}
+	if err != nil {
+		return errors.Wrap(err, "failed to marshal Spec file")
+	}
+
+	dir = filepath.Dir(s.path)
+	err = os.MkdirAll(dir, 0o755)
+	if err != nil {
+		return errors.Wrap(err, "failed to create Spec dir")
+	}
+
+	tmp, err = os.CreateTemp(dir, "spec.*.tmp")
+	if err != nil {
+		return errors.Wrap(err, "failed to create Spec file")
+	}
+	_, err = tmp.Write(data)
+	tmp.Close()
+	if err != nil {
+		return errors.Wrap(err, "failed to write Spec file")
+	}
+
+	err = renameIn(dir, filepath.Base(tmp.Name()), filepath.Base(s.path), overwrite)
+
+	if err != nil {
+		os.Remove(tmp.Name())
+		err = errors.Wrap(err, "failed to write Spec file")
+	}
+
+	return err
+}
+
 // GetVendor returns the vendor of this Spec.
 func (s *Spec) GetVendor() string {
 	return s.vendor
@@ -183,8 +234,8 @@ func validateVersion(version string) error {
 	return nil
 }
 
-// Parse raw CDI Spec file data.
-func parseSpec(data []byte) (*cdi.Spec, error) {
+// ParseSpec parses CDI Spec data into a raw CDI Spec.
+func ParseSpec(data []byte) (*cdi.Spec, error) {
 	var raw *cdi.Spec
 	err := yaml.UnmarshalStrict(data, &raw)
 	if err != nil {