Azure Schema Registry client library for Python
Azure Schema Registry is a schema repository service hosted by Azure Event Hubs, providing schema storage, versioning,
and management. The registry is leveraged by encoders to reduce payload size while describing payload structure with
schema identifiers rather than full schemas. This package provides:
-
A client library to register and retrieve schemas and their respective properties.
-
An JSON schema-based encoder capable of encoding and decoding payloads containing
Schema Registry schema identifiers, corresponding to JSON schemas used for validation, and encoded content.
Source code
| Package (PyPi)
| Package (Conda)
| API reference documentation
| Samples
| Changelog
Disclaimer
Azure SDK Python packages support for Python 2.7 has ended on 01 January 2022. For more information and questions, please refer to https://github.com/Azure/azure-sdk-for-python/issues/20691
Getting started
Install the package
Install the Azure Schema Registry client library for Python with pip:
pip install azure-schemaregistry
To use the built-in jsonschema
validators with the JSON Schema Encoder, install jsonencoder
extras:
pip install azure-schemaregistry[jsonencoder]
Prerequisites:
To use this package, you must have:
Authenticate the client
Interaction with Schema Registry starts with an instance of SchemaRegistryClient class. The client constructor takes an Azure Event Hubs fully qualified namespace and an Azure Active Directory credential:
-
The fully qualified namespace of the Schema Registry instance should follow the format: <yournamespace>.servicebus.windows.net
.
-
An AAD credential that implements the TokenCredential protocol should be passed to the constructor. There are implementations of the TokenCredential
protocol available in the
azure-identity package. To use the credential types provided by azure-identity
, please install the Azure Identity client library for Python with pip:
pip install azure-identity
- Additionally, to use the async API, you must first install an async transport, such as aiohttp:
pip install aiohttp
Create client using the azure-identity library:
from azure.schemaregistry import SchemaRegistryClient
from azure.identity import DefaultAzureCredential
credential = DefaultAzureCredential()
fully_qualified_namespace = os.environ['SCHEMAREGISTRY_FULLY_QUALIFIED_NAMESPACE']
schema_registry_client = SchemaRegistryClient(fully_qualified_namespace, credential)
Create JsonSchemaEncoder using the azure-schemaregistry library:
import os
from azure.schemaregistry import SchemaRegistryClient
from azure.schemaregistry.encoder.jsonencoder import JsonSchemaEncoder
from azure.identity import DefaultAzureCredential
credential = DefaultAzureCredential()
fully_qualified_namespace = os.environ['SCHEMAREGISTRY_FULLY_QUALIFIED_NAMESPACE']
group_name = os.environ['SCHEMAREGISTRY_GROUP']
schema_registry_client = SchemaRegistryClient(fully_qualified_namespace, credential)
encoder = JsonSchemaEncoder(client=schema_registry_client, group_name=group_name)
Key concepts
Client concepts
-
Schema: Schema is the organization or structure for data. More detailed information can be found here.
-
Schema Group: A logical group of similar schemas based on business criteria, which can hold multiple versions of a schema. More detailed information can be found here.
-
SchemaRegistryClient: SchemaRegistryClient
provides the API for storing and retrieving schemas in schema registry.
Encoder concepts
-
JsonSchemaEncoder: Provides API to encode content to and decode content from Binary Encoding, validate content against a JSON Schema, and cache schemas/schema IDs retrived from the registry using the SchemaRegistryClient
locally.
-
OutboundMessageContent: Protocol defined under azure.schemaregistry
that allows for JsonSchemaEncoder.encode
interoperability with certain Azure Messaging SDK message types. Support has been added to:
azure.eventhub.EventData
for azure-eventhub>=5.9.0
-
InboundMessageContent: Protocol defined under azure.schemaregistry
that allows for JsonSchemaEncoder.decode
interoperability with certain Azure Messaging SDK message types. Support has been added to:
azure.eventhub.EventData
for azure-eventhub>=5.9.0
OutboundMessageContent/InboundMessageContent
If a message type that follows the OutboundMessageContent protocol is provided to the JsonSchemaEncoder
, it will set the corresponding content and content type properties. If a message type object that follows the InboundMessageContent protocol is provided to the encoder, it will get the corresponding content and content type properties. These are defined as:
-
content
: Binary-encoded, JSON schema-validated payload (in general, format-specific payload)
-
content type
: a string of the format application/json;serialization=Json+<schema ID>
, where:
application/json;serialization=Json
is the format indicator<schema ID>
is the hexadecimal representation of GUID, same format and byte order as the string from the Schema Registry service.
If EventData
is passed in as the message type, the following properties will be set on the EventData
object:
If message type is not provided, and by default, the encoder will create the following dict:
{"content": <encoded payload>, "content_type": 'application/json;serialization=Json+<schema ID>'}
Examples
The following sections provide several code snippets covering some of the most common Schema Registry and Json Schema Encoder tasks, including:
Register a schema
Use SchemaRegistryClient.register_schema
method to register a schema.
import os
from azure.identity import DefaultAzureCredential
from azure.schemaregistry import SchemaRegistryClient
token_credential = DefaultAzureCredential()
fully_qualified_namespace = os.environ['SCHEMAREGISTRY_AVRO_FULLY_QUALIFIED_NAMESPACE']
group_name = os.environ['SCHEMA_REGISTRY_GROUP']
name = "your-schema-name"
format = "Avro"
definition = """
{"namespace": "example.avro",
"type": "record",
"name": "User",
"fields": [
{"name": "name", "type": "string"},
{"name": "favorite_number", "type": ["int", "null"]},
{"name": "favorite_color", "type": ["string", "null"]}
]
}
"""
schema_registry_client = SchemaRegistryClient(fully_qualified_namespace=fully_qualified_namespace, credential=token_credential)
with schema_registry_client:
schema_properties = schema_registry_client.register_schema(group_name, name, definition, format)
id = schema_properties.id
Get the schema by id
Get the schema definition and its properties by schema id.
import os
from azure.identity import DefaultAzureCredential
from azure.schemaregistry import SchemaRegistryClient
token_credential = DefaultAzureCredential()
fully_qualified_namespace = os.environ['SCHEMAREGISTRY_AVRO_FULLY_QUALIFIED_NAMESPACE']
schema_id = 'your-schema-id'
schema_registry_client = SchemaRegistryClient(fully_qualified_namespace=fully_qualified_namespace, credential=token_credential)
with schema_registry_client:
schema = schema_registry_client.get_schema(schema_id)
definition = schema.definition
properties = schema.properties
Get the schema by version
Get the schema definition and its properties by schema version.
import os
from azure.identity import DefaultAzureCredential
from azure.schemaregistry import SchemaRegistryClient
token_credential = DefaultAzureCredential()
fully_qualified_namespace = os.environ['SCHEMAREGISTRY_AVRO_FULLY_QUALIFIED_NAMESPACE']
group_name = os.environ["SCHEMAREGISTRY_GROUP"]
name = "your-schema-name"
version = int("<your schema version>")
schema_registry_client = SchemaRegistryClient(fully_qualified_namespace=fully_qualified_namespace, credential=token_credential)
with schema_registry_client:
schema = schema_registry_client.get_schema(group_name=group_name, name=name, version=version)
definition = schema.definition
properties = schema.properties
Get the id of a schema
Get the schema id of a schema by schema definition and its properties.
import os
from azure.identity import DefaultAzureCredential
from azure.schemaregistry import SchemaRegistryClient
token_credential = DefaultAzureCredential()
fully_qualified_namespace = os.environ['SCHEMAREGISTRY_AVRO_FULLY_QUALIFIED_NAMESPACE']
group_name = os.environ['SCHEMA_REGISTRY_GROUP']
name = "your-schema-name"
format = "Avro"
definition = """
{"namespace": "example.avro",
"type": "record",
"name": "User",
"fields": [
{"name": "name", "type": "string"},
{"name": "favorite_number", "type": ["int", "null"]},
{"name": "favorite_color", "type": ["string", "null"]}
]
}
"""
schema_registry_client = SchemaRegistryClient(fully_qualified_namespace=fully_qualified_namespace, credential=token_credential)
with schema_registry_client:
schema_properties = schema_registry_client.register_schema(group_name, name, definition, format)
id = schema_properties.id
Encode
Use the SchemaRegistryClient
to pre-register the schema. Encode and validate the content with the JsonSchemaEncoder
.
The encode
method automatically retrieves the schema from the Schema Registry Service, validates against the content, and caches the schema locally.
import os
import json
from azure.schemaregistry import SchemaRegistryClient, SchemaFormat
from azure.schemaregistry.encoder.jsonencoder import JsonSchemaEncoder
from azure.identity import DefaultAzureCredential
from azure.eventhub import EventData
token_credential = DefaultAzureCredential()
fully_qualified_namespace = os.environ['SCHEMAREGISTRY_JSON_FULLY_QUALIFIED_NAMESPACE']
group_name = os.environ['SCHEMAREGISTRY_GROUP']
format = SchemaFormat.JSON
DRAFT2020_12_SCHEMA_IDENTIFIER = "https://json-schema.org/draft/2020-12/schema"
schema = {
"$id": "https://example.com/person.schema.json",
"$schema": "https://json-schema.org/draft/2020-12/schema",
"title": "Person",
"type": "object",
"properties": {
"name": {
"type": "string",
"description": "Person's name."
},
"favorite_color": {
"type": "string",
"description": "Favorite color."
},
"favorite_number": {
"description": "Favorite number.",
"type": "integer",
}
}
}
name = schema["title"]
definition = json.dumps(schema)
schema_registry_client = SchemaRegistryClient(fully_qualified_namespace, token_credential)
schema_properties = schema_registry_client.register_schema(group_name, name, definition, format)
schema_id = schema_properties.id
encoder = JsonSchemaEncoder(client=schema_registry_client, validate=DRAFT2020_12_SCHEMA_IDENTIFIER, group_name=group_name)
with encoder:
dict_content = {"name": "Ben", "favorite_number": 7, "favorite_color": "red"}
event_data = encoder.encode(dict_content, schema_id=schema_id, message_type=EventData)
message_content_dict = encoder.encode(dict_content, schema_id=schema_id)
event_data = EventData.from_message_content(message_content_dict["content"], message_content_dict["content_type"])
dict_content = {"name": "Ben", "favorite_number": 7, "favorite_color": "red"}
message_content = encoder.encode(dict_content, schema=definition)
Decode
Decode the content with the JsonSchemaEncoder
.
The decode
method automatically retrieves the schema from the Schema Registry Service, validates against the content, and caches the schema locally.
import os
from azure.schemaregistry import SchemaRegistryClient
from azure.schemaregistry.encoder.jsonencoder import JsonSchemaEncoder
from azure.identity import DefaultAzureCredential
token_credential = DefaultAzureCredential()
fully_qualified_namespace = os.environ['SCHEMAREGISTRY_FULLY_QUALIFIED_NAMESPACE']
group_name = os.environ["SCHEMAREGISTRY_GROUP"]
DRAFT2020_12_SCHEMA_IDENTIFIER = "https://json-schema.org/draft/2020-12/schema"
schema_registry_client = SchemaRegistryClient(fully_qualified_namespace, token_credential)
encoder = JsonSchemaEncoder(client=schema_registry_client, validate=DRAFT2020_12_SCHEMA_IDENTIFIER)
with encoder:
decoded_content = encoder.decode(event_data)
decoded_content = encoder.decode(content_dict)
Event Hubs Send Integration
Integration with Event Hubs to send an EventData
object with body
set to encoded content and corresponding content_type
.
import os
from azure.eventhub import EventHubProducerClient, EventData
from azure.schemaregistry import SchemaRegistryClient
from azure.schemaregistry.encoder.jsonencoder import JsonSchemaEncoder
from azure.identity import DefaultAzureCredential
token_credential = DefaultAzureCredential()
fully_qualified_namespace = os.environ['SCHEMAREGISTRY_JSON_FULLY_QUALIFIED_NAMESPACE']
group_name = os.environ['SCHEMAREGISTRY_GROUP']
eventhub_connection_str = os.environ['EVENT_HUB_CONN_STR']
eventhub_name = os.environ['EVENT_HUB_NAME']
schema_id = os.environ['PERSON_JSON_SCHEMA_ID']
DRAFT2020_12_SCHEMA_IDENTIFIER = "https://json-schema.org/draft/2020-12/schema"
schema_registry_client = SchemaRegistryClient(fully_qualified_namespace, token_credential)
json_schema_encoder = JsonSchemaEncoder(client=schema_registry_client, validate=DRAFT2020_12_SCHEMA_IDENTIFIER)
eventhub_producer = EventHubProducerClient.from_connection_string(
conn_str=eventhub_connection_str,
eventhub_name=eventhub_name
)
with eventhub_producer, json_schema_encoder:
event_data_batch = eventhub_producer.create_batch()
dict_content = {"name": "Bob", "favorite_number": 7, "favorite_color": "red"}
event_data = json_schema_encoder.encode(dict_content, schema_id=schema_id, message_type=EventData)
event_data_batch.add(event_data)
eventhub_producer.send_batch(event_data_batch)
Event Hubs Receive Integration
Integration with Event Hubs to receive an EventData
object and decode the encoded body
value.
import os
from azure.eventhub import EventHubConsumerClient
from azure.schemaregistry import SchemaRegistryClient
from azure.schemaregistry.encoder.jsonencoder import JsonSchemaEncoder
from azure.identity import DefaultAzureCredential
token_credential = DefaultAzureCredential()
fully_qualified_namespace = os.environ['SCHEMAREGISTRY_JSON_FULLY_QUALIFIED_NAMESPACE']
group_name = os.environ['SCHEMAREGISTRY_GROUP']
eventhub_connection_str = os.environ['EVENT_HUB_CONN_STR']
eventhub_name = os.environ['EVENT_HUB_NAME']
DRAFT2020_12_SCHEMA_IDENTIFIER = "https://json-schema.org/draft/2020-12/schema"
schema_registry_client = SchemaRegistryClient(fully_qualified_namespace, token_credential)
json_schema_encoder = JsonSchemaEncoder(client=schema_registry_client, validate=DRAFT2020_12_SCHEMA_IDENTIFIER)
eventhub_consumer = EventHubConsumerClient.from_connection_string(
conn_str=eventhub_connection_str,
consumer_group='$Default',
eventhub_name=eventhub_name,
)
def on_event(partition_context, event):
decoded_content = json_schema_encoder.decode(event)
with eventhub_consumer, json_schema_encoder:
eventhub_consumer.receive(on_event=on_event, starting_position="-1")
Troubleshooting
General
Schema Registry clients raise exceptions defined in Azure Core if errors are encountered when communicating with the Schema Registry service.
Errors when encoding and decoding related to invalid content/content types will be raised as azure.schemaregistry.encoder.jsonencoder.InvalidContentError
, where __cause__
will possibly contain an underlying exception.
Logging
This library uses the standard
logging library for logging.
Basic information about HTTP sessions (URLs, headers, etc.) is logged at INFO
level.
Detailed DEBUG level logging, including request/response bodies and unredacted
headers, can be enabled on a client with the logging_enable
argument:
import sys
import os
import logging
from azure.schemaregistry import SchemaRegistryClient
from azure.schemaregistry.encoder.jsonencoder import JsonSchemaEncoder
from azure.identity import DefaultAzureCredential
logger = logging.getLogger('azure.schemaregistry')
logger.setLevel(logging.DEBUG)
handler = logging.StreamHandler(stream=sys.stdout)
logger.addHandler(handler)
fully_qualified_namespace = os.environ['SCHEMAREGISTRY_FULLY_QUALIFIED_NAMESPACE']
group_name = os.environ['SCHEMAREGISTRY_GROUP']
DRAFT2020_12_SCHEMA_IDENTIFIER = "https://json-schema.org/draft/2020-12/schema"
credential = DefaultAzureCredential()
schema_registry_client = SchemaRegistryClient(fully_qualified_namespace, credential, logging_enable=True)
encoder = JsonSchemaEncoder(client=schema_registry_client, validate=DRAFT2020_12_SCHEMA_IDENTIFIER)
Similarly, logging_enable
can enable detailed logging for a single operation,
even when it isn't enabled for the client:
schema_registry_client.get_schema(schema_id, logging_enable=True)
Next steps
More sample code
Please take a look at the samples directory for detailed examples of how to use this library to register and retrieve schema to/from Schema Registry.
Contributing
This project welcomes contributions and suggestions. Most contributions require you to agree to a
Contributor License Agreement (CLA) declaring that you have the right to, and actually do, grant us
the rights to use your contribution. For details, visit https://cla.microsoft.com.
When you submit a pull request, a CLA-bot will automatically determine whether you need to provide
a CLA and decorate the PR appropriately (e.g., label, comment). Simply follow the instructions
provided by the bot. You will only need to do this once across all repos using our CLA.
This project has adopted the Microsoft Open Source Code of Conduct.
For more information see the Code of Conduct FAQ or
contact opencode@microsoft.com with any additional questions or comments.
Release History
1.3.0 (2024-09-18)
This version and all future versions will require Python 3.8+. Python 3.7 is no longer supported.
Features Added
- Sync and async
JsonSchemaEncoder
have been added under azure.schemaregistry.encoder.jsonencoder
. InvalidContentError
have been added under azure.schemaregistry.encoder.jsonencoder
for use with the JsonSchemaEncoder
.MessageContent
, OutboundMessageContent
,InboundMessageContent
, and SchemaContentValidate
have been added under azure.schemaregistry
as protocols for use with the JsonSchemaEncoder
and/or future encoder implementations.Json
and Custom
have been added to supported formats in SchemaFormat
.V2022_10
has been added to ApiVersion
and set as the default API version.
Bugs Fixed
- Fixed a bug in sync/async
register_schema
and get_schema_properties
that did not accept case insensitive strings as an argument to the format
parameter. - Fixed a bug where unknown content type strings from the service raised a client error, rather than being returned as a string in the SchemaProperties
format
property.
Other Changes
- Updated azure-core minimum dependency to 1.28.0.
- Added support for Python 3.11 and 3.12.
- The following features have been temporarily pulled out and will be added back in future previews as we work towards a stable release:
V2023_07_01
in ApiVersion
.
PROTOBUF
in SchemaFormat
.
1.3.0b3 (2023-11-09)
Features Added
V2023_07_01
has been added to ApiVersion
and set as the default API version.
Protobuf
has been added to supported formats in SchemaFormat
.
Other Changes
- Added support for Python 3.12.
1.3.0b2 (2023-08-09)
Features Added
The following features are experimental and may be removed:
- Sync and async
JsonSchemaEncoder
have been added under azure.schemaregistry.encoder.jsonencoder
. InvalidContentError
and JsonSchemaDraftIdentifier
have been added under azure.schemaregistry.encoder.jsonencoder
for use with the JsonSchemaEncoder
.MessageType
, MessageContent
, SchemaContentValidate
, SchemaEncoder
have been added under azure.schemaregistry
as protocols to define/for use with the JsonSchemaEncoder
and future encoder implementations.
1.3.0b1 (2023-01-12)
Features Added
V2022_10
has been added to ApiVersion
and set as the default api version.
Json
and Custom
have been added to supported formats in SchemaFormat
.- At the time of this release, only Draft 3 of JSON schemas is currently supported by the service.
Bugs Fixed
- Fixed a bug in sync/async
register_schema
and get_schema_properties
that did not accept case insensitive strings as an argument to the format
parameter.
Other Changes
- Added support for Python 3.11.
1.2.0 (2022-10-10)
This version and all future versions will require Python 3.7+, Python 3.6 is no longer supported.
Features Added
group_name
, name
, and version
have been added as optional parameters to the get_schema
method on the sync and async SchemaRegistryClient
.version
has been added to SchemaProperties
.
Other Changes
- Updated azure-core minimum dependency to 1.24.0.
- Added distributed tracing support for sync and async
SchemaRegistryClient
.
1.1.0 (2022-05-10)
This version and all future versions will require Python 3.6+. Python 2.7 is no longer supported.
Features Added
group_name
and name
have been added as instance variables to SchemaProperties
.
Other Changes
- Updated azure-core minimum dependency to 1.23.0.
1.0.0 (2021-11-10)
Note: This is the first stable release of our efforts to create a user-friendly and Pythonic client library for Azure Schema Registry.
Features Added
SchemaRegistryClient
is the top-level client class interacting with the Azure Schema Registry Service. It provides three methods:
register_schema
: Store schema in the service by providing schema group name, schema name, schema definition, and schema format.get_schema
: Get schema definition and its properties by schema id.get_schema_properties
: Get schema properties by providing schema group name, schema name, schema definition, and schema format.
SchemaProperties
has the following instance variables: id
and format
:
- The type of
format
has been changed from str
to SchemaFormat
.
Schema
has the following properties: properties
and definition
.SchemaFormat
provides the schema format to be stored by the service. Currently, the only supported format is Avro
.api_version
has been added as a keyword arg to the sync and async SchemaRegistryClient
constructors.
Breaking Changes
version
instance variable in SchemaProperties
has been removed.schema_definition
instance variable in Schema
has been renamed definition
.id
parameter in get_schema
method on sync and async SchemaRegistryClient
has been renamed schema_id
.schema_definition
parameter in register_schema
and get_schema_properties
methods on sync and async SchemaRegistryClient
has been renamed definition
.serializer
namespace has been removed from azure.schemaregistry
.
1.0.0b3 (2021-10-05)
Breaking Changes
get_schema_id
method on sync and async SchemaRegistryClient
has been renamed get_schema_properties
.schema_id
parameter in get_schema
method on sync and async SchemaRegistryClient
has been renamed id
.register_schema
and get_schema_properties
methods on sync and async SchemaRegistryClient
now take in the following parameters in the given order:
group_name
, which has been renamed from schema_group
name
, which has been renamed from schema_name
schema_definition
, which has been renamed from schema_content
format
, which has been renamed from serialization_type
endpoint
parameter in SchemaRegistryClient
constructor has been renamed fully_qualified_namespace
location
instance variable in SchemaProperties
has been removed.Schema
and SchemaProperties
no longer have positional parameters, as they will not be constructed by the user.
Other Changes
- Updated azure-core dependency to 1.19.0.
- Removed caching support of registered schemas so requests are sent to the service to register schemas, get schema properties, and get schemas.
1.0.0b2 (2021-08-17)
This version and all future versions will require Python 2.7 or Python 3.6+, Python 3.5 is no longer supported.
Features Added
- Support caching of registered schemas and send requests to the service only if the cache does not have the looked-up schema/schema ID.
1.0.0b1 (2020-09-09)
Version 1.0.0b1 is the first preview of our efforts to create a user-friendly and Pythonic client library for Azure Schema Registry.
New features
SchemaRegistryClient
is the top-level client class interacting with the Azure Schema Registry Service. It provides three methods:
register_schema
: Store schema into the service.get_schema
: Get schema content and its properties by schema id.get_schema_id
: Get schema id and its properties by schema group, schema name, serialization type and schema content.