#!/usr/bin/env python # -*- coding: utf-8 -*- # # Copyright 2020 Confluent Inc. # # 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. import io import orjson from typing import Union, Optional, Tuple, Callable from cachetools import LRUCache from jsonschema import ValidationError from jsonschema.protocols import Validator from jsonschema.validators import validator_for from referencing import Registry, Resource from confluent_kafka.schema_registry import (Schema, topic_subject_name_strategy, RuleMode, SchemaRegistryClient, prefix_schema_id_serializer, dual_schema_id_deserializer) from confluent_kafka.schema_registry.common.json_schema import ( DEFAULT_SPEC, JsonSchema, _retrieve_via_httpx, transform, _ContextStringIO, JSON_TYPE ) from confluent_kafka.schema_registry.common.schema_registry_client import \ RulePhase from confluent_kafka.schema_registry.rule_registry import RuleRegistry from confluent_kafka.schema_registry.serde import BaseSerializer, BaseDeserializer, \ ParsedSchemaCache, SchemaId from confluent_kafka.serialization import (SerializationError, SerializationContext) __all__ = [ '_resolve_named_schema', 'JSONSerializer', 'JSONDeserializer' ] def _resolve_named_schema( schema: Schema, schema_registry_client: SchemaRegistryClient, ref_registry: Optional[Registry] = None ) -> Registry: """ Resolves named schemas referenced by the provided schema recursively. :param schema: Schema to resolve named schemas for. :param schema_registry_client: SchemaRegistryClient to use for retrieval. :param ref_registry: Registry of named schemas resolved recursively. :return: Registry """ if ref_registry is None: # Retrieve external schemas for backward compatibility ref_registry = Registry(retrieve=_retrieve_via_httpx) if schema.references is not None: for ref in schema.references: referenced_schema = schema_registry_client.get_version(ref.subject, ref.version, True) ref_registry = _resolve_named_schema(referenced_schema.schema, schema_registry_client, ref_registry) referenced_schema_dict = orjson.loads(referenced_schema.schema.schema_str) resource = Resource.from_contents( referenced_schema_dict, default_specification=DEFAULT_SPEC) ref_registry = ref_registry.with_resource(ref.name, resource) return ref_registry class JSONSerializer(BaseSerializer): """ Serializer that outputs JSON encoded data with Confluent Schema Registry framing. Configuration properties: +-----------------------------+----------+----------------------------------------------------+ | Property Name | Type | Description | +=============================+==========+====================================================+ | | | If True, automatically register the configured | | ``auto.register.schemas`` | bool | schema with Confluent Schema Registry if it has | | | | not previously been associated with the relevant | | | | subject (determined via subject.name.strategy). | | | | | | | | Defaults to True. | | | | | | | | Raises SchemaRegistryError if the schema was not | | | | registered against the subject, or could not be | | | | successfully registered. | +-----------------------------+----------+----------------------------------------------------+ | | | Whether to normalize schemas, which will | | ``normalize.schemas`` | bool | transform schemas to have a consistent format, | | | | including ordering properties and references. | +-----------------------------+----------+----------------------------------------------------+ | | | Whether to use the given schema ID for | | ``use.schema.id`` | int | serialization. | +-----------------------------+----------+----------------------------------------------------+ | | | Whether to use the latest subject version for | | ``use.latest.version`` | bool | serialization. | | | | | | | | WARNING: There is no check that the latest | | | | schema is backwards compatible with the object | | | | being serialized. | | | | | | | | Defaults to False. | +-----------------------------+----------+----------------------------------------------------+ | | | Whether to use the latest subject version with | | ``use.latest.with.metadata``| dict | the given metadata. | | | | | | | | WARNING: There is no check that the latest | | | | schema is backwards compatible with the object | | | | being serialized. | | | | | | | | Defaults to None. | +-----------------------------+----------+----------------------------------------------------+ | | | Callable(SerializationContext, str) -> str | | | | | | ``subject.name.strategy`` | callable | Defines how Schema Registry subject names are | | | | constructed. Standard naming strategies are | | | | defined in the confluent_kafka.schema_registry | | | | namespace. | | | | | | | | Defaults to topic_subject_name_strategy. | +-----------------------------+----------+----------------------------------------------------+ | | | Whether to validate the payload against the | | ``validate`` | bool | the given schema. | | | | | +-----------------------------+----------+----------------------------------------------------+ | | | Callable(bytes, SerializationContext, schema_id) | | | | -> bytes | | | | | | ``schema.id.serializer`` | callable | Defines how the schema id/guid is serialized. | | | | Defaults to prefix_schema_id_serializer. | +-----------------------------+----------+----------------------------------------------------+ Schemas are registered against subject names in Confluent Schema Registry that define a scope in which the schemas can be evolved. By default, the subject name is formed by concatenating the topic name with the message field (key or value) separated by a hyphen. i.e. {topic name}-{message field} Alternative naming strategies may be configured with the property ``subject.name.strategy``. Supported subject name strategies: +--------------------------------------+------------------------------+ | Subject Name Strategy | Output Format | +======================================+==============================+ | topic_subject_name_strategy(default) | {topic name}-{message field} | +--------------------------------------+------------------------------+ | topic_record_subject_name_strategy | {topic name}-{record name} | +--------------------------------------+------------------------------+ | record_subject_name_strategy | {record name} | +--------------------------------------+------------------------------+ See `Subject name strategy `_ for additional details. Notes: The ``title`` annotation, referred to elsewhere as a record name is not strictly required by the JSON Schema specification. It is however required by this serializer in order to register the schema with Confluent Schema Registry. Prior to serialization, all objects must first be converted to a dict instance. This may be handled manually prior to calling :py:func:`Producer.produce()` or by registering a `to_dict` callable with JSONSerializer. Args: schema_str (str, Schema): `JSON Schema definition. `_ Accepts schema as either a string or a :py:class:`Schema` instance. Note that string definitions cannot reference other schemas. For referencing other schemas, use a :py:class:`Schema` instance. schema_registry_client (SchemaRegistryClient): Schema Registry client instance. to_dict (callable, optional): Callable(object, SerializationContext) -> dict. Converts object to a dict. conf (dict): JsonSerializer configuration. """ # noqa: E501 __slots__ = ['_known_subjects', '_parsed_schema', '_ref_registry', '_schema', '_schema_id', '_schema_name', '_to_dict', '_parsed_schemas', '_validators', '_validate', '_json_encode'] _default_conf = {'auto.register.schemas': True, 'normalize.schemas': False, 'use.schema.id': None, 'use.latest.version': False, 'use.latest.with.metadata': None, 'subject.name.strategy': topic_subject_name_strategy, 'schema.id.serializer': prefix_schema_id_serializer, 'validate': True} def __init_impl( self, schema_str: Union[str, Schema, None], schema_registry_client: SchemaRegistryClient, to_dict: Optional[Callable[[object, SerializationContext], dict]] = None, conf: Optional[dict] = None, rule_conf: Optional[dict] = None, rule_registry: Optional[RuleRegistry] = None, json_encode: Optional[Callable] = None, ): super().__init__() if isinstance(schema_str, str): self._schema = Schema(schema_str, schema_type="JSON") elif isinstance(schema_str, Schema): self._schema = schema_str else: self._schema = None self._json_encode = json_encode or (lambda x: orjson.dumps(x).decode("utf-8")) self._registry = schema_registry_client self._rule_registry = ( rule_registry if rule_registry else RuleRegistry.get_global_instance() ) self._schema_id = None self._known_subjects = set() self._parsed_schemas = ParsedSchemaCache() self._validators = LRUCache(1000) if to_dict is not None and not callable(to_dict): raise ValueError("to_dict must be callable with the signature " "to_dict(object, SerializationContext)->dict") self._to_dict = to_dict conf_copy = self._default_conf.copy() if conf is not None: conf_copy.update(conf) self._auto_register = conf_copy.pop('auto.register.schemas') if not isinstance(self._auto_register, bool): raise ValueError("auto.register.schemas must be a boolean value") self._normalize_schemas = conf_copy.pop('normalize.schemas') if not isinstance(self._normalize_schemas, bool): raise ValueError("normalize.schemas must be a boolean value") self._use_schema_id = conf_copy.pop('use.schema.id') if (self._use_schema_id is not None and not isinstance(self._use_schema_id, int)): raise ValueError("use.schema.id must be an int value") self._use_latest_version = conf_copy.pop('use.latest.version') if not isinstance(self._use_latest_version, bool): raise ValueError("use.latest.version must be a boolean value") if self._use_latest_version and self._auto_register: raise ValueError("cannot enable both use.latest.version and auto.register.schemas") self._use_latest_with_metadata = conf_copy.pop('use.latest.with.metadata') if (self._use_latest_with_metadata is not None and not isinstance(self._use_latest_with_metadata, dict)): raise ValueError("use.latest.with.metadata must be a dict value") self._subject_name_func = conf_copy.pop('subject.name.strategy') if not callable(self._subject_name_func): raise ValueError("subject.name.strategy must be callable") self._schema_id_serializer = conf_copy.pop('schema.id.serializer') if not callable(self._schema_id_serializer): raise ValueError("schema.id.serializer must be callable") self._validate = conf_copy.pop('validate') if not isinstance(self._validate, bool): raise ValueError("validate must be a boolean value") if len(conf_copy) > 0: raise ValueError("Unrecognized properties: {}" .format(", ".join(conf_copy.keys()))) schema_dict, ref_registry = self._get_parsed_schema(self._schema) if schema_dict: schema_name = schema_dict.get('title', None) else: schema_name = None self._schema_name = schema_name self._parsed_schema = schema_dict self._ref_registry = ref_registry for rule in self._rule_registry.get_executors(): rule.configure(self._registry.config() if self._registry else {}, rule_conf if rule_conf else {}) __init__ = __init_impl def __call__(self, obj: object, ctx: Optional[SerializationContext] = None) -> Optional[bytes]: return self.__serialize(obj, ctx) def __serialize(self, obj: object, ctx: Optional[SerializationContext] = None) -> Optional[bytes]: """ Serializes an object to JSON, prepending it with Confluent Schema Registry framing. Args: obj (object): The object instance to serialize. ctx (SerializationContext): Metadata relevant to the serialization operation. Raises: SerializerError if any error occurs serializing obj. Returns: bytes: None if obj is None, else a byte array containing the JSON serialized data with Confluent Schema Registry framing. """ if obj is None: return None subject = self._subject_name_func(ctx, self._schema_name) latest_schema = self._get_reader_schema(subject) if latest_schema is not None: self._schema_id = SchemaId(JSON_TYPE, latest_schema.schema_id, latest_schema.guid) elif subject not in self._known_subjects: # Check to ensure this schema has been registered under subject_name. if self._auto_register: # The schema name will always be the same. We can't however register # a schema without a subject so we set the schema_id here to handle # the initial registration. registered_schema = self._registry.register_schema_full_response( subject, self._schema, normalize_schemas=self._normalize_schemas) self._schema_id = SchemaId(JSON_TYPE, registered_schema.schema_id, registered_schema.guid) else: registered_schema = self._registry.lookup_schema( subject, self._schema, normalize_schemas=self._normalize_schemas) self._schema_id = SchemaId(JSON_TYPE, registered_schema.schema_id, registered_schema.guid) self._known_subjects.add(subject) if self._to_dict is not None: value = self._to_dict(obj, ctx) else: value = obj if latest_schema is not None: schema = latest_schema.schema parsed_schema, ref_registry = self._get_parsed_schema(latest_schema.schema) root_resource = Resource.from_contents( parsed_schema, default_specification=DEFAULT_SPEC) ref_resolver = ref_registry.resolver_with_root(root_resource) def field_transformer(rule_ctx, field_transform, msg): return ( # noqa: E731 transform(rule_ctx, parsed_schema, ref_registry, ref_resolver, "$", msg, field_transform)) value = self._execute_rules(ctx, subject, RuleMode.WRITE, None, latest_schema.schema, value, None, field_transformer) else: schema = self._schema parsed_schema, ref_registry = self._parsed_schema, self._ref_registry if self._validate: try: validator = self._get_validator(schema, parsed_schema, ref_registry) validator.validate(value) except ValidationError as ve: raise SerializationError(ve.message) with _ContextStringIO() as fo: # JSON dump always writes a str never bytes # https://docs.python.org/3/library/json.html encoded_value = self._json_encode(value) if isinstance(encoded_value, str): encoded_value = encoded_value.encode("utf8") fo.write(encoded_value) buffer = fo.getvalue() if latest_schema is not None: buffer = self._execute_rules_with_phase( ctx, subject, RulePhase.ENCODING, RuleMode.WRITE, None, latest_schema.schema, buffer, None, None) return self._schema_id_serializer(buffer, ctx, self._schema_id) def _get_parsed_schema(self, schema: Schema) -> Tuple[Optional[JsonSchema], Optional[Registry]]: if schema is None: return None, None result = self._parsed_schemas.get_parsed_schema(schema) if result is not None: return result ref_registry = _resolve_named_schema(schema, self._registry) parsed_schema = orjson.loads(schema.schema_str) self._parsed_schemas.set(schema, (parsed_schema, ref_registry)) return parsed_schema, ref_registry def _get_validator(self, schema: Schema, parsed_schema: JsonSchema, registry: Registry) -> Validator: validator = self._validators.get(schema, None) if validator is not None: return validator cls = validator_for(parsed_schema) cls.check_schema(parsed_schema) validator = cls(parsed_schema, registry=registry) self._validators[schema] = validator return validator class JSONDeserializer(BaseDeserializer): """ Deserializer for JSON encoded data with Confluent Schema Registry framing. Configuration properties: +-----------------------------+----------+----------------------------------------------------+ | Property Name | Type | Description | +=============================+==========+====================================================+ +-----------------------------+----------+----------------------------------------------------+ | | | Whether to use the latest subject version for | | ``use.latest.version`` | bool | deserialization. | | | | | | | | Defaults to False. | +-----------------------------+----------+----------------------------------------------------+ | | | Whether to use the latest subject version with | | ``use.latest.with.metadata``| dict | the given metadata. | | | | | | | | Defaults to None. | +-----------------------------+----------+----------------------------------------------------+ | | | Callable(SerializationContext, str) -> str | | | | | | ``subject.name.strategy`` | callable | Defines how Schema Registry subject names are | | | | constructed. Standard naming strategies are | | | | defined in the confluent_kafka.schema_registry | | | | namespace. | | | | | | | | Defaults to topic_subject_name_strategy. | +-----------------------------+----------+----------------------------------------------------+ | | | Whether to validate the payload against the | | ``validate`` | bool | the given schema. | | | | | +-----------------------------+----------+----------------------------------------------------+ | | | Callable(bytes, SerializationContext, schema_id) | | | | -> io.BytesIO | | | | | | ``schema.id.deserializer`` | callable | Defines how the schema id/guid is deserialized. | | | | Defaults to dual_schema_id_deserializer. | +-----------------------------+----------+----------------------------------------------------+ Args: schema_str (str, Schema, optional): `JSON schema definition `_ Accepts schema as either a string or a :py:class:`Schema` instance. Note that string definitions cannot reference other schemas. For referencing other schemas, use a :py:class:`Schema` instance. If not provided, schemas will be retrieved from schema_registry_client based on the schema ID in the wire header of each message. from_dict (callable, optional): Callable(dict, SerializationContext) -> object. Converts a dict to a Python object instance. schema_registry_client (SchemaRegistryClient, optional): Schema Registry client instance. Needed if ``schema_str`` is a schema referencing other schemas or is not provided. """ # noqa: E501 __slots__ = ['_reader_schema', '_ref_registry', '_from_dict', '_schema', '_parsed_schemas', '_validators', '_validate', '_json_decode'] _default_conf = {'use.latest.version': False, 'use.latest.with.metadata': None, 'subject.name.strategy': topic_subject_name_strategy, 'schema.id.deserializer': dual_schema_id_deserializer, 'validate': True} def __init_impl( self, schema_str: Union[str, Schema, None], from_dict: Optional[Callable[[dict, SerializationContext], object]] = None, schema_registry_client: Optional[SchemaRegistryClient] = None, conf: Optional[dict] = None, rule_conf: Optional[dict] = None, rule_registry: Optional[RuleRegistry] = None, json_decode: Optional[Callable] = None, ): super().__init__() if isinstance(schema_str, str): schema = Schema(schema_str, schema_type="JSON") elif isinstance(schema_str, Schema): schema = schema_str if bool(schema.references) and schema_registry_client is None: raise ValueError( """schema_registry_client must be provided if "schema_str" is a Schema instance with references""") elif schema_str is None: if schema_registry_client is None: raise ValueError( """schema_registry_client must be provided if "schema_str" is not provided""" ) schema = schema_str else: raise TypeError('You must pass either str or Schema') self._schema = schema self._registry = schema_registry_client self._rule_registry = rule_registry if rule_registry else RuleRegistry.get_global_instance() self._parsed_schemas = ParsedSchemaCache() self._validators = LRUCache(1000) self._json_decode = json_decode or orjson.loads self._use_schema_id = None conf_copy = self._default_conf.copy() if conf is not None: conf_copy.update(conf) self._use_latest_version = conf_copy.pop('use.latest.version') if not isinstance(self._use_latest_version, bool): raise ValueError("use.latest.version must be a boolean value") self._use_latest_with_metadata = conf_copy.pop('use.latest.with.metadata') if (self._use_latest_with_metadata is not None and not isinstance(self._use_latest_with_metadata, dict)): raise ValueError("use.latest.with.metadata must be a dict value") self._subject_name_func = conf_copy.pop('subject.name.strategy') if not callable(self._subject_name_func): raise ValueError("subject.name.strategy must be callable") self._schema_id_deserializer = conf_copy.pop('schema.id.deserializer') if not callable(self._subject_name_func): raise ValueError("schema.id.deserializer must be callable") self._validate = conf_copy.pop('validate') if not isinstance(self._validate, bool): raise ValueError("validate must be a boolean value") if len(conf_copy) > 0: raise ValueError("Unrecognized properties: {}" .format(", ".join(conf_copy.keys()))) if schema: self._reader_schema, self._ref_registry = self._get_parsed_schema(self._schema) else: self._reader_schema, self._ref_registry = None, None if from_dict is not None and not callable(from_dict): raise ValueError("from_dict must be callable with the signature" " from_dict(dict, SerializationContext) -> object") self._from_dict = from_dict for rule in self._rule_registry.get_executors(): rule.configure(self._registry.config() if self._registry else {}, rule_conf if rule_conf else {}) __init__ = __init_impl def __call__(self, data: bytes, ctx: Optional[SerializationContext] = None) -> Optional[bytes]: return self.__deserialize(data, ctx) def __deserialize(self, data: bytes, ctx: Optional[SerializationContext] = None) -> Optional[bytes]: """ Deserialize a JSON encoded record with Confluent Schema Registry framing to a dict, or object instance according to from_dict if from_dict is specified. Args: data (bytes): A JSON serialized record with Confluent Schema Registry framing. ctx (SerializationContext): Metadata relevant to the serialization operation. Returns: A dict, or object instance according to from_dict if from_dict is specified. Raises: SerializerError: If there was an error reading the Confluent framing data, or if ``data`` was not successfully validated with the configured schema. """ if data is None: return None subject = self._subject_name_func(ctx, None) latest_schema = None if subject is not None and self._registry is not None: latest_schema = self._get_reader_schema(subject) schema_id = SchemaId(JSON_TYPE) payload = self._schema_id_deserializer(data, ctx, schema_id) if self._registry is not None: writer_schema_raw = self._get_writer_schema(schema_id, subject) writer_schema, writer_ref_registry = self._get_parsed_schema(writer_schema_raw) if subject is None: subject = self._subject_name_func(ctx, writer_schema.get("title")) if subject is not None: latest_schema = self._get_reader_schema(subject) else: writer_schema_raw = None writer_schema, writer_ref_registry = None, None payload = self._execute_rules_with_phase( ctx, subject, RulePhase.ENCODING, RuleMode.READ, None, writer_schema_raw, payload, None, None) if isinstance(payload, bytes): payload = io.BytesIO(payload) # JSON documents are self-describing; no need to query schema obj_dict = self._json_decode(payload.read()) if latest_schema is not None: migrations = self._get_migrations(subject, writer_schema_raw, latest_schema, None) reader_schema_raw = latest_schema.schema reader_schema, reader_ref_registry = self._get_parsed_schema(latest_schema.schema) elif self._schema is not None: migrations = None reader_schema_raw = self._schema reader_schema, reader_ref_registry = self._reader_schema, self._ref_registry else: migrations = None reader_schema_raw = writer_schema_raw reader_schema, reader_ref_registry = writer_schema, writer_ref_registry if migrations: obj_dict = self._execute_migrations(ctx, subject, migrations, obj_dict) reader_root_resource = Resource.from_contents( reader_schema, default_specification=DEFAULT_SPEC) reader_ref_resolver = reader_ref_registry.resolver_with_root(reader_root_resource) def field_transformer(rule_ctx, field_transform, message): return ( # noqa: E731 transform(rule_ctx, reader_schema, reader_ref_registry, reader_ref_resolver, "$", message, field_transform)) obj_dict = self._execute_rules(ctx, subject, RuleMode.READ, None, reader_schema_raw, obj_dict, None, field_transformer) if self._validate: try: validator = self._get_validator(reader_schema_raw, reader_schema, reader_ref_registry) validator.validate(obj_dict) except ValidationError as ve: raise SerializationError(ve.message) if self._from_dict is not None: return self._from_dict(obj_dict, ctx) return obj_dict def _get_parsed_schema(self, schema: Schema) -> Tuple[Optional[JsonSchema], Optional[Registry]]: if schema is None: return None, None result = self._parsed_schemas.get_parsed_schema(schema) if result is not None: return result ref_registry = _resolve_named_schema(schema, self._registry) parsed_schema = orjson.loads(schema.schema_str) self._parsed_schemas.set(schema, (parsed_schema, ref_registry)) return parsed_schema, ref_registry def _get_validator(self, schema: Schema, parsed_schema: JsonSchema, registry: Registry) -> Validator: validator = self._validators.get(schema, None) if validator is not None: return validator cls = validator_for(parsed_schema) cls.check_schema(parsed_schema) validator = cls(parsed_schema, registry=registry) self._validators[schema] = validator return validator