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Python SDK for Tags

In this guide, we will use the Python SDK to create Tags. A prerequisite for this section is to have previously gone through the following docs. In the following sections we will:
  • Create a Database Service, a Database, a Schema and one Table,
  • Create a Classification,
  • Create a Tag for the Classification and add it to the Table.

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Creating the Entities

To prepare the necessary ingredients, execute the following steps.

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1. Preparing the Client

from metadata.generated.schema.entity.services.connections.metadata.openMetadataConnection import (
    OpenMetadataConnection,
)
from metadata.generated.schema.security.client.openMetadataJWTClientConfig import (
    OpenMetadataJWTClientConfig,
)
from metadata.ingestion.ometa.ometa_api import OpenMetadata

server_config = OpenMetadataConnection(
    hostPort="http://localhost:8585/api",
    authProvider="openmetadata",
    securityConfig=OpenMetadataJWTClientConfig(
        jwtToken="<token>"
    ),
)
metadata = OpenMetadata(server_config)

assert metadata.health_check()  # Will fail if we cannot reach the server

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2. Creating the Database Service

We are mocking a MySQL instance. Note how we need to pass the right configuration class MysqlConnection, as a parameter for the generic DatabaseConnection type. 
from metadata.generated.schema.api.services.createDatabaseService import (
    CreateDatabaseServiceRequest,
)
from metadata.generated.schema.entity.services.connections.database.common.basicAuth import (
    BasicAuth,
)
from metadata.generated.schema.entity.services.connections.database.mysqlConnection import (
    MysqlConnection,
)
from metadata.generated.schema.entity.services.databaseService import (
    DatabaseConnection,
    DatabaseService,
    DatabaseServiceType,
)

db_service = CreateDatabaseServiceRequest(
    name="test-service-db-lineage",
    serviceType=DatabaseServiceType.Mysql,
    connection=DatabaseConnection(
        config=MysqlConnection(
            username="username",
            authType=BasicAuth(password="password"),
            hostPort="http://localhost:1234",
        )
    ),
)

db_service_entity = metadata.create_or_update(data=db_service)

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3. Creating the Database

Any Entity that is created and linked to another Entity, has to hold the fullyQualifiedName to the Entity it relates to. In this case, a Database is bound to a specific service. 
from metadata.generated.schema.api.data.createDatabase import CreateDatabaseRequest

create_db = CreateDatabaseRequest(
    name="test-db",
    service=db_service_entity.EntityName,
)

create_db_entity = metadata.create_or_update(data=create_db)

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4. Creating the Schema

The same happens with the Schemas. They are related to a Database. 
from metadata.generated.schema.api.data.createDatabaseSchema import (
    CreateDatabaseSchemaRequest,
)

create_schema = CreateDatabaseSchemaRequest(
    name="test-schema", database=create_db_entity.fullyQualifiedName
)

create_schema_entity = metadata.create_or_update(data=create_schema)

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5. Creating the Table

We are doing a simple example with a single column. 
from metadata.generated.schema.api.data.createTable import CreateTableRequest
from metadata.generated.schema.entity.data.table import Column, DataType

table = CreateTableRequest(
    name="my_table",
    databaseSchema=create_schema_entity.fullyQualifiedName,
    columns=[Column(name="id", dataType=DataType.BIGINT)],
)

table = metadata.create_or_update(data=table)

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6. Creating the Classification

Classifications are the entities we use to group tag definitions. Let’s create a sample one: 
from metadata.generated.schema.api.classification.createClassification import (
    CreateClassificationRequest,
)
from metadata.generated.schema.api.classification.createTag import CreateTagRequest

classification_request=CreateClassificationRequest(
    name="TestClassification",
    description="Sample classification.",
)

metadata.create_or_update(classification_request)

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7. Creating the Tag

Once there is an existing classification, we create tags within that given classification: 
tag_request=CreateTagRequest(
    classification=classification_request.name,
    name="TestTag",
    description="Sample Tag.",
)

metadata.create_or_update(tag_request)

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8. Tagging a Table

Now that we have the Tag, we can proceed and tag a specific asset. In this example, we’ll tag the Table we created above. For that, the API uses a PATCH request, but the Python SDK has a helper method that handles most of the work: 
from metadata.generated.schema.entity.data.table import Table

metadata.patch_tag(
    entity=Table,
    entity_id=table.id,
    tag_fqn="TestClassification.TestTag",
)
If we now check the tags for the Table, the new tag will be appearing in there. Note that we now used the patch_tag method because the Table already existed. If we can control the Tag creation process when the Table metadata is generated, we can assign the tags in the tags property of CreateTableRequest.

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9. Tagging a Column

The same idea can be replicated to tag a column: 
metadata.patch_column_tag(
    entity_id=table.id,
    tag_fqn="TestClassification.TestTag",
    column_name="id",
)