add validator

pkg/jsonschema/compiler.go

@@ -0,0 +1,75 @@
+package jsonschema
+
+import (
+	"context"
+	"fmt"
+	"strings"
+
+	"github.com/metal-toolbox/governor-api/internal/models"
+	"github.com/santhosh-tekuri/jsonschema/v5"
+	"github.com/volatiletech/sqlboiler/v4/boil"
+)
+
+// Compiler is a struct for a JSON schema compiler
+type Compiler struct {
+	jsonschema.Compiler
+
+	extensionID   string
+	erdSlugPlural string
+	version       string
+}
+
+// Option is a functional configuration option for JSON schema compiler
+type Option func(c *Compiler)
+
+// NewCompiler configures and creates a new JSON schema compiler
+func NewCompiler(
+	extensionID, slugPlural, version string,
+	opts ...Option,
+) *Compiler {
+	c := &Compiler{*jsonschema.NewCompiler(), extensionID, slugPlural, version}
+
+	for _, opt := range opts {
+		opt(c)
+	}
+
+	return c
+}
+
+// WithUniqueConstraint enables the unique constraint extension for a JSON
+// schema. An extra `unique` field can be added to the JSON schema, and the
+// Validator will ensure that the combination of every properties in the
+// array is unique within the given extension resource definition.
+// Note that unique constraint validation will be skipped if db is nil.
+func WithUniqueConstraint(
+	ctx context.Context,
+	extensionResourceDefinition *models.ExtensionResourceDefinition,
+	resourceID *string,
+	db boil.ContextExecutor,
+) Option {
+	return func(c *Compiler) {
+		c.RegisterExtension(
+			"uniqueConstraint",
+			JSONSchemaUniqueConstraint,
+			&UniqueConstraintCompiler{extensionResourceDefinition, resourceID, ctx, db},
+		)
+	}
+}
+
+func (c *Compiler) schemaURL() string {
+	return fmt.Sprintf(
+		"https://governor/extensions/%s/erds/%s/%s/schema.json",
+		c.extensionID, c.erdSlugPlural, c.version,
+	)
+}
+
+// Compile compiles the schema string
+func (c *Compiler) Compile(schema string) (*jsonschema.Schema, error) {
+	url := c.schemaURL()
+
+	if err := c.AddResource(url, strings.NewReader(schema)); err != nil {
+		return nil, err
+	}
+
+	return c.Compiler.Compile(url)
+}

pkg/jsonschema/doc.go

@@ -0,0 +1,3 @@
+// Package jsonschema provides a JSON schema validator that is tailored for
+// validations of governor's Extension Resources
+package jsonschema

pkg/jsonschema/errors.go

@@ -0,0 +1,13 @@
+package jsonschema
+
+import "errors"
+
+var (
+	// ErrInvalidUniqueProperty is returned when the schema's unique property
+	// is invalid
+	ErrInvalidUniqueProperty = errors.New(`property "unique" is invalid`)
+
+	// ErrUniqueConstraintViolation is returned when an object violates the unique
+	// constrain
+	ErrUniqueConstraintViolation = errors.New("unique constraint violation")
+)

pkg/jsonschema/unique_constraint.go

@@ -0,0 +1,229 @@
+package jsonschema
+
+import (
+	"context"
+	"fmt"
+	"reflect"
+
+	"github.com/metal-toolbox/governor-api/internal/models"
+	"github.com/santhosh-tekuri/jsonschema/v5"
+	"github.com/volatiletech/sqlboiler/v4/boil"
+	"github.com/volatiletech/sqlboiler/v4/queries/qm"
+)
+
+// JSONSchemaUniqueConstraint is a JSON schema extension that provides a
+// "unique" property of type array
+var JSONSchemaUniqueConstraint = jsonschema.MustCompileString(
+	"https://governor/json-schemas/unique.json",
+	`{
+		"properties": {
+			"unique": {
+				"type": "array",
+				"items": {
+					"type": "string"
+				}
+			}
+		}
+	}`,
+)
+
+// UniqueConstraintSchema is the schema struct for the unique constraint JSON schema extension
+type UniqueConstraintSchema struct {
+	UniqueFieldTypesMap map[string]string
+	ERD                 *models.ExtensionResourceDefinition
+	ResourceID          *string
+	ctx                 context.Context
+	db                  boil.ContextExecutor
+}
+
+// UniqueConstraintSchema implements jsonschema.ExtSchema
+var _ jsonschema.ExtSchema = (*UniqueConstraintSchema)(nil)
+
+// Validate checks the uniqueness of the provided value against a database
+// to ensure the unique constraint is satisfied.
+func (s *UniqueConstraintSchema) Validate(_ jsonschema.ValidationContext, v interface{}) error {
+	// Skip validation if no database is provided
+	if s.db == nil {
+		return nil
+	}
+
+	// Skip validation if no constraint is provided
+	if len(s.UniqueFieldTypesMap) == 0 {
+		return nil
+	}
+
+	// Try to assert the provided value as a map, skip validation otherwise
+	mappedValue, ok := v.(map[string]interface{})
+	if !ok {
+		return nil
+	}
+
+	qms := []qm.QueryMod{}
+
+	if s.ResourceID != nil {
+		qms = append(qms, qm.Where("id != ?", *s.ResourceID))
+	}
+
+	for k, value := range mappedValue {
+		// Convert the value to string
+		v := fmt.Sprint(value)
+
+		fieldType, exists := s.UniqueFieldTypesMap[k]
+		if !exists {
+			continue
+		}
+
+		if fieldType == "string" {
+			v = fmt.Sprintf(`"%s"`, v)
+		}
+
+		qms = append(qms, qm.Where(`resource->? = ?`, k, v))
+	}
+
+	exists, err := s.ERD.SystemExtensionResources(qms...).Exists(s.ctx, s.db)
+	if err != nil {
+		return &jsonschema.ValidationError{
+			Message: err.Error(),
+		}
+	}
+
+	if exists {
+		return &jsonschema.ValidationError{
+			InstanceLocation: s.ERD.Name,
+			KeywordLocation:  "unique",
+			Message:          ErrUniqueConstraintViolation.Error(),
+		}
+	}
+
+	return nil
+}
+
+// UniqueConstraintCompiler is the compiler struct for the unique constraint JSON schema extension
+type UniqueConstraintCompiler struct {
+	ERD        *models.ExtensionResourceDefinition
+	ResourceID *string
+	ctx        context.Context
+	db         boil.ContextExecutor
+}
+
+// UniqueConstraintCompiler implements jsonschema.ExtCompiler
+var _ jsonschema.ExtCompiler = (*UniqueConstraintCompiler)(nil)
+
+// Compile compiles the unique constraint JSON schema extension
+func (uc *UniqueConstraintCompiler) Compile(
+	_ jsonschema.CompilerContext, m map[string]interface{},
+) (jsonschema.ExtSchema, error) {
+	unique, ok := m["unique"]
+	if !ok {
+		// If "unique" is not in the map, skip processing
+		return nil, nil
+	}
+
+	uniqueFields, err := assertStringSlice(unique)
+	if err != nil {
+		return nil, err
+	}
+
+	if len(uniqueFields) == 0 {
+		// unique property is not provided, skip
+		return nil, nil
+	}
+
+	requiredFields, err := assertStringSlice(m["required"])
+	if err != nil {
+		return nil, err
+	}
+
+	requiredMap := make(map[string]bool, len(requiredFields))
+	for _, f := range requiredFields {
+		requiredMap[f] = true
+	}
+
+	propertiesMap, ok := m["properties"].(map[string]interface{})
+	if !ok {
+		return nil, fmt.Errorf(
+			`%w: cannot apply unique constraint when "properties" is not provided or invalid`,
+			ErrInvalidUniqueProperty,
+		)
+	}
+
+	return uc.compileUniqueConstraint(uniqueFields, requiredMap, propertiesMap)
+}
+
+func (uc *UniqueConstraintCompiler) compileUniqueConstraint(
+	uniqueFields []string, requiredMap map[string]bool, propertiesMap map[string]interface{},
+) (jsonschema.ExtSchema, error) {
+	// map fieldName => fieldType
+	resultUniqueFields := make(map[string]string)
+
+	for _, fieldName := range uniqueFields {
+		if !requiredMap[fieldName] {
+			return nil, fmt.Errorf(
+				`%w: unique property needs to be a required property, "%s" is not in "required"`,
+				ErrInvalidUniqueProperty,
+				fieldName,
+			)
+		}
+
+		prop, ok := propertiesMap[fieldName]
+		if !ok {
+			return nil, fmt.Errorf(
+				`%w: missing property definition for unique field "%s"`,
+				ErrInvalidUniqueProperty,
+				fieldName,
+			)
+		}
+
+		fieldType, ok := prop.(map[string]interface{})["type"].(string)
+		if !ok || !isValidType(fieldType) {
+			return nil, fmt.Errorf(
+				`%w: invalid type "%s" for unique field "%s"`,
+				ErrInvalidUniqueProperty,
+				fieldType,
+				fieldName,
+			)
+		}
+
+		resultUniqueFields[fieldName] = fieldType
+	}
+
+	return &UniqueConstraintSchema{resultUniqueFields, uc.ERD, uc.ResourceID, uc.ctx, uc.db}, nil
+}
+
+// Checks if the provided field type is valid for unique constraints
+func isValidType(fieldType string) bool {
+	_, ok := map[string]bool{
+		"string": true, "number": true, "integer": true, "boolean": true,
+	}[fieldType]
+
+	return ok
+}
+
+// helper function to assert string slice type
+func assertStringSlice(value interface{}) ([]string, error) {
+	values, ok := value.([]interface{})
+	if !ok {
+		return nil, fmt.Errorf(
+			`%w: unable to convert %v to string array`,
+			ErrInvalidUniqueProperty,
+			reflect.TypeOf(value),
+		)
+	}
+
+	strs := make([]string, len(values))
+
+	for i, v := range values {
+		str, ok := v.(string)
+		if !ok {
+			return nil, fmt.Errorf(
+				`%w: unable to convert %v to string`,
+				ErrInvalidUniqueProperty,
+				reflect.TypeOf(v),
+			)
+		}
+
+		strs[i] = str
+	}
+
+	return strs, nil
+}