Merge pull request #62 from klihub/devel/split-out-schema-validation

Don't force downstream code pulling in (the huge) JSON Schema validation package.

Author: elezar

cmd/cdi/cmd/root.go

@@ -23,6 +23,8 @@ import (
 	"github.com/spf13/cobra"
 
 	"github.com/container-orchestrated-devices/container-device-interface/pkg/cdi"
+	"github.com/container-orchestrated-devices/container-device-interface/pkg/cdi/validate"
+	"github.com/container-orchestrated-devices/container-device-interface/schema"
 )
 
 var (
@@ -58,14 +60,17 @@ func init() {
 }
 
 func initSpecDirs() {
-	err := cdi.SetSchema(schemaName)
+	s, err := schema.Load(schemaName)
 	if err != nil {
 		fmt.Printf("failed to load JSON schema %s: %v\n", schemaName, err)
 		os.Exit(1)
 	}
+	cdi.SetSpecValidator(validate.WithSchema(s))
 
 	if len(specDirs) > 0 {
-		cdi.GetRegistry(cdi.WithSpecDirs(specDirs...))
+		cdi.GetRegistry(
+			cdi.WithSpecDirs(specDirs...),
+		)
 		if len(cdi.GetRegistry().GetErrors()) > 0 {
 			cdiPrintRegistryErrors()
 		}

pkg/cdi/schema.go

@@ -35,6 +35,9 @@ var (
 		"0.2.0": {},
 		"0.3.0": {},
 	}
+
+	// Externally set CDI Spec validation function.
+	specValidator func(*cdi.Spec) error
 )
 
 // Spec represents a single CDI Spec. It is usually loaded from a
@@ -85,7 +88,7 @@ func ReadSpec(path string, priority int) (*Spec, error) {
 // priority. If Spec data validation fails NewSpec returns a nil
 // Spec and an error.
 func NewSpec(raw *cdi.Spec, path string, priority int) (*Spec, error) {
-	err := validateWithSchema(raw)
+	err := validateSpec(raw)
 	if err != nil {
 		return nil, err
 	}
@@ -188,3 +191,22 @@ func parseSpec(data []byte) (*cdi.Spec, error) {
 	}
 	return raw, nil
 }
+
+// SetSpecValidator sets a CDI Spec validator function. This function
+// is used for extra CDI Spec content validation whenever a Spec file
+// loaded (using ReadSpec() or NewSpec()) or written (Spec.Write()).
+func SetSpecValidator(fn func(*cdi.Spec) error) {
+	specValidator = fn
+}
+
+// validateSpec validates the Spec using the extneral validator.
+func validateSpec(raw *cdi.Spec) error {
+	if specValidator == nil {
+		return nil
+	}
+	err := specValidator(raw)
+	if err != nil {
+		return errors.Wrap(err, "Spec validation failed")
+	}
+	return nil
+}

pkg/cdi/spec.go

@@ -0,0 +1,58 @@
+/*
+   Copyright © 2022 The CDI Authors
+
+   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 validate
+
+import (
+	"github.com/container-orchestrated-devices/container-device-interface/schema"
+	raw "github.com/container-orchestrated-devices/container-device-interface/specs-go"
+)
+
+const (
+	// DefaultExternalSchema is the default JSON schema to load for validation.
+	DefaultExternalSchema = "/etc/cdi/schema/schema.json"
+)
+
+// WithSchema returns a CDI Spec validator that uses the given Schema.
+func WithSchema(s *schema.Schema) func(*raw.Spec) error {
+	if s == nil {
+		return func(*raw.Spec) error {
+			return nil
+		}
+	}
+	return func(spec *raw.Spec) error {
+		return s.ValidateType(spec)
+	}
+}
+
+// WithNamedSchema loads the named JSON schema and returns a CDI Spec
+// validator for it. If loading the schema fails a dummy validator is
+// returned.
+func WithNamedSchema(name string) func(*raw.Spec) error {
+	s, _ := schema.Load(name)
+	return WithSchema(s)
+}
+
+// WithDefaultSchema returns a CDI Spec validator that uses the default
+// external JSON schema, or the default builtin one if the external one
+// fails to load.
+func WithDefaultSchema() func(*raw.Spec) error {
+	s, err := schema.Load(DefaultExternalSchema)
+	if err == nil {
+		return WithSchema(s)
+	}
+	return WithSchema(schema.BuiltinSchema())
+}

pkg/cdi/validate/schema.go

@@ -34,13 +34,10 @@ import (
 )
 
 const (
-	// BuiltinSchemaName references the builtin schema for Load()/Set().
+	// BuiltinSchemaName names the builtin schema for Load()/Set().
 	BuiltinSchemaName = "builtin"
-	// NoneSchemaName references a disabled/NOP schema for Load()/Set().
+	// NoneSchemaName names the NOP-schema for Load()/Set().
 	NoneSchemaName = "none"
-	// DefaultSchemaName is the none schema.
-	DefaultSchemaName = NoneSchemaName
-
 	// builtinSchemaFile is the builtin schema URI in our embedded FS.
 	builtinSchemaFile = "file:///schema.json"
 )
@@ -65,8 +62,26 @@ func Get() *Schema {
 	return current
 }
 
-// BuiltinSchema returns the builtin validating JSON Schema.
+// BuiltinSchema returns the builtin schema if we have a valid one. Otherwise
+// it falls back to NopSchema().
 func BuiltinSchema() *Schema {
+	if builtin != nil {
+		return builtin
+	}
+
+	s, err := schema.NewSchema(
+		schema.NewReferenceLoaderFileSystem(
+			builtinSchemaFile,
+			http.FS(builtinFS),
+		),
+	)
+
+	if err == nil {
+		builtin = &Schema{schema: s}
+	} else {
+		builtin = NopSchema()
+	}
+
 	return builtin
 }
 
@@ -229,25 +244,8 @@ var (
 	// our builtin schema
 	builtin *Schema
 	// currently loaded schema, builtin by default
-	current *Schema
+	current = BuiltinSchema()
 )
 
 //go:embed *.json
 var builtinFS embed.FS
-
-func init() {
-	s, err := schema.NewSchema(
-		schema.NewReferenceLoaderFileSystem(
-			builtinSchemaFile,
-			http.FS(builtinFS),
-		),
-	)
-
-	if err != nil {
-		builtin = NopSchema()
-	} else {
-		builtin = &Schema{schema: s}
-	}
-
-	current = builtin
-}