chore(interfaces): move data-bigdata schemas to the new format

interfaces/connect_client/interface/v0/schema.py

@@ -1,17 +1,32 @@
-"""This file defines the schemas for the provider and requirer sides  of `connect_client` charm relation interface.
+"""This file defines the schemas for the provider and requirer sides  of `connect_client` charm relation interface."""
 
-It exposes two interfaces.schema_base.DataBagSchema subclasses called:
-- ProviderSchema
-- RequirerSchema
-"""
+import json
+from typing import Any
 
-from interface_tester.schema_base import DataBagSchema
-from pydantic import BaseModel, Field
+from pydantic import BaseModel, ConfigDict, Field, field_serializer, field_validator
 
 PLUGIN_URL_NOT_REQUIRED = "NOT-REQUIRED"
 
 
-class ConnectProviderData(BaseModel):
+class _BareStringDatabag(BaseModel):
+    """Base class for databag models that don't strictly JSON encode all entries."""
+
+    @staticmethod
+    def __juju_decoder__(value: str) -> str:
+        """Pass Juju's string through unmodified to be decoded by individual field validators."""
+        return value
+
+    @staticmethod
+    def __juju_encoder__(value: str | None) -> str:
+        """Convert `None` to "", erasing the value; Ops will error on a non-string."""
+        return "" if value is None else value
+
+
+class ProviderAppData(_BareStringDatabag):
+    """The provider's application databag."""
+
+    model_config = ConfigDict(strict=True, populate_by_name=True)
+
     endpoints: str = Field(
         description="A comma-separated list of Kafka Connect REST endpoint(s), including the protocol (either `http` or `https`)",
         examples=["http://10.1.1.100:8083,http://10.1.1.101:8083,http://10.1.1.102:8083"],
@@ -32,7 +47,11 @@ class ConnectProviderData(BaseModel):
     )
 
 
-class ConnectRequirerData(BaseModel):
+class RequirerAppData(_BareStringDatabag):
+    """The requirer's application databag."""
+
+    model_config = ConfigDict(strict=True, populate_by_name=True)
+
     plugin_url: str = Field(
         description=f'URL at which the plugins required by this client are served as a single Tarball. If not required, the requirer should place the sentinel value "{PLUGIN_URL_NOT_REQUIRED}"',
         alias="plugin-url",
@@ -41,19 +60,24 @@ class ConnectRequirerData(BaseModel):
     )
     requested_secrets: list[str] = Field(
         alias="requested-secrets",
-        description="Any provider field which should be transfered as Juju Secret",
+        description="Any provider field which should be transfered as Juju Secret. A JSON array on the wire.",
         examples=[["username", "password", "tls-ca"]],
         title="Requested secrets",
     )
 
+    @field_validator("requested_secrets", mode="before")
+    @classmethod
+    def _load_json(cls, value: Any) -> Any:
+        if not isinstance(value, str):
+            return value  # __init__ argument was already deserialized.
+        return json.loads(value)
 
-class ProviderSchema(DataBagSchema):
-    """The schema for the provider side of the `connect_client` interface."""
-
-    app: ConnectProviderData
-
+    @field_serializer("requested_secrets")
+    def _dump_json(self, value: object) -> str | None:
+        if value is None:
+            return None
+        return json.dumps(value)
 
-class RequirerSchema(DataBagSchema):
-    """The schema for the requirer side of the `connect_client` interface."""
 
-    app: ConnectRequirerData
+ProviderUnitData = None
+RequirerUnitData = None

interfaces/kafka_client/interface/v0/schema.py

@@ -1,14 +1,8 @@
-"""This file defines the schemas for the provider and requirer sides of the kafka_client interface.
-
-It must expose two interfaces.schema_base.DataBagSchema subclasses called:
-- ProviderSchema
-- RequirerSchema
-"""
+"""This file defines the schemas for the provider and requirer sides of the kafka_client interface."""
 
 from enum import Enum
 
-from interface_tester.schema_base import DataBagSchema
-from pydantic import BaseModel, Field, field_validator
+from pydantic import BaseModel, ConfigDict, Field, field_validator
 
 
 class ExtraUserRole(str, Enum):
@@ -17,87 +11,105 @@ class ExtraUserRole(str, Enum):
     producer = "producer"
 
 
-class KafkaProviderData(BaseModel):
+class _BareStringDatabag(BaseModel):
+    """Base class for databag models that don't strictly JSON encode all entries."""
+
+    @staticmethod
+    def __juju_decoder__(value: str) -> str:
+        """Pass Juju's string through unmodified to be decoded by individual field validators."""
+        return value
+
+    @staticmethod
+    def __juju_encoder__(value: str | None) -> str:
+        """Convert `None` to "", erasing the value; Ops will error on a non-string."""
+        return "" if value is None else value
+
+
+class ProviderAppData(_BareStringDatabag):
     """The databag for the provider side of this interface."""
 
+    model_config = ConfigDict(strict=True, populate_by_name=True)
+
     topic: str = Field(
-        description="The topic that has been made available to the relation user. Name defined in the Requirer's topic field",
+        description="The topic that has been made available to the relation user. Name defined in the Requirer's topic field. A bare string on the wire",
         examples=["topic-1", "appname-*"],
         title="Topic name",
     )
 
     username: str = Field(
-        description="Username for connecting to the Kafka cluster",
+        description="Username for connecting to the Kafka cluster. A bare string on the wire, but usually delivered in a Juju secret instead, in which case the key is absent from the databag",
         examples=["relation-14"],
         title="Kafka SASL/SCRAM username",
     )
 
     password: str = Field(
-        description="Password for connecting to the Kafka cluster",
+        description="Password for connecting to the Kafka cluster. A bare string on the wire, but usually delivered in a Juju secret instead, in which case the key is absent from the databag",
         examples=["alphanum-32byte-random"],
         title="Kafka SASL/SCRAM password",
     )
 
     endpoints: str = Field(
-        description="A list of endpoints used to connect to the topic",
+        description="A list of endpoints used to connect to the topic. A bare string on the wire, comma separated if there is more than one endpoint",
         examples=["10.141.78.155:9092,10.141.78.62:9092,10.141.78.186:9092"],
         title="Kafka server endpoints",
     )
 
     consumer_group_prefix: str | None = Field(
         None,
         alias="consumer-group-prefix",
-        description="A prefix for wildcard consumer-group IDs that have been granted permissions",
+        description="A prefix for wildcard consumer-group IDs that have been granted permissions. A bare string on the wire",
         examples=["relation-14-"],
         title="Kafka consumer group prefix",
     )
 
     zookeeper_uris: str | None = Field(
         None,
-        alias="consumer-group-prefix",
-        description="A comma-seperated list of Zookeeper server URIs, and Kafka cluster zNode",
+        alias="zookeeper-uris",
+        description="A comma-seperated list of Zookeeper server URIs, and Kafka cluster zNode. A bare string on the wire",
         examples=["10.141.78.155:2181,10.141.78.62:2181,10.141.78.186:2181/kafka"],
         title="Zookeeper URIs",
     )
 
     entity_name: str | None = Field(
         None,
         alias="entity-name",
-        description="Name for the requested custom entity",
+        description="Name for the requested custom entity. A bare string on the wire, but usually delivered in a Juju secret instead, in which case the key is absent from the databag",
         examples=["custom-role"],
         title="Entity name",
     )
 
     entity_password: str | None = Field(
         None,
         alias="entity-password",
-        description="Password for the requested custom entity",
+        description="Password for the requested custom entity. A bare string on the wire, but usually delivered in a Juju secret instead, in which case the key is absent from the databag",
         examples=["alphanum-32byte-random"],
         title="Entity password",
     )
 
 
-class KafkaRequirerData(BaseModel):
+class RequirerAppData(_BareStringDatabag):
     """The databag for the requirer side of this interface."""
 
+    model_config = ConfigDict(strict=True, populate_by_name=True)
+
     topic: str = Field(
-        description="The topic name access requested by the requirer",
+        description="The topic name access requested by the requirer. A bare string on the wire",
         examples=["topic-1", "appname-*"],
         title="Topic name",
     )
 
     consumer_group_prefix: str | None = Field(
         None,
         alias="consumer-group-prefix",
-        description="A prefix for wildcard consumer-group IDs that have been granted permissions",
+        description="A prefix for wildcard consumer-group IDs that have been granted permissions. A bare string on the wire",
         examples=["relation-14-"],
         title="Kafka consumer group prefix",
     )
 
     extra_user_roles: str | None = Field(
         None,
         alias="extra-user-roles",
-        description="Any extra user roles requested by the requirer",
+        description="Any extra user roles requested by the requirer. A bare string on the wire, comma separated if there is more than one role",
         examples=[
             "consumer",
             "producer",
@@ -113,23 +125,23 @@ class KafkaRequirerData(BaseModel):
     extra_group_roles: str | None = Field(
         None,
         alias="extra-group-roles",
-        description="Any extra group roles requested by the requirer",
+        description="Any extra group roles requested by the requirer. A bare string on the wire, comma separated if there is more than one role",
         examples=["charmed_read"],
         title="Extra group roles",
     )
 
     entity_type: str | None = Field(
         None,
         alias="entity-type",
-        description="Type of the requested entity (user / group)",
+        description="Type of the requested entity (user / group). A bare string on the wire",
         examples=["USER", "GROUP"],
         title="Entity type",
     )
 
     entity_permissions: str | None = Field(
         None,
         alias="entity-permissions",
-        description="List of permissions to assign to the custom entity, in JSON format",
+        description="List of permissions to assign to the custom entity, in JSON format. The library treats this as an opaque string, so it is written to the databag as-is rather than being re-encoded",
         examples=[
             "[{\"resource_name\": \"messages\", \"resource_type\": \"TOPIC\", \"privileges\": [\"READ\"]}]"
         ],
@@ -148,13 +160,5 @@ def capitalize(cls, value: str) -> str:
         return value
 
 
-class ProviderSchema(DataBagSchema):
-    """The schema for the provider side of this interface."""
-
-    app: KafkaProviderData
-
-
-class RequirerSchema(DataBagSchema):
-    """The schema for the requirer side of this interface."""
-
-    app: KafkaRequirerData
+ProviderUnitData = None
+RequirerUnitData = None

interfaces/karapace_client/interface/v0/schema.py

@@ -1,24 +1,34 @@
-"""This file defines the schemas for the provider and requirer sides of the karapace_client interface.
-
-It must expose two interfaces.schema_base.DataBagSchema subclasses called:
-- ProviderSchema
-- RequirerSchema
-"""
+"""This file defines the schemas for the provider and requirer sides of the karapace_client interface."""
 
 from enum import Enum
 
-from interface_tester.schema_base import DataBagSchema
-from pydantic import BaseModel, Field, field_validator
+from pydantic import BaseModel, ConfigDict, Field, field_validator
 
 
 class ExtraUserRole(str, Enum):
     admin = "admin"
     user = "user"
 
 
-class KarapaceProviderData(BaseModel):
+class _BareStringDatabag(BaseModel):
+    """Base class for databag models that don't strictly JSON encode all entries."""
+
+    @staticmethod
+    def __juju_decoder__(value: str) -> str:
+        """Pass Juju's string through unmodified to be decoded by individual field validators."""
+        return value
+
+    @staticmethod
+    def __juju_encoder__(value: str | None) -> str:
+        """Convert `None` to "", erasing the value; Ops will error on a non-string."""
+        return "" if value is None else value
+
+
+class ProviderAppData(_BareStringDatabag):
     """The databag for the provider side of this interface."""
 
+    model_config = ConfigDict(strict=True, populate_by_name=True)
+
     subject: str = Field(
         description="The subject that has been made available to the relation user. Name defined in the Requirer's subject field",
         examples=["subject-1"],
@@ -38,7 +48,7 @@ class KarapaceProviderData(BaseModel):
     )
 
     endpoints: str = Field(
-        description="A list of endpoints used to connect to the subject",
+        description="A list of endpoints used to connect to the subject, comma separated on the wire",
         examples=["10.141.78.155:8082,10.141.78.62:8082,10.141.78.186:8082"],
         title="Karapace server endpoints",
     )
@@ -60,9 +70,11 @@ class KarapaceProviderData(BaseModel):
     )
 
 
-class KarapaceRequirerData(BaseModel):
+class RequirerAppData(_BareStringDatabag):
     """The databag for the requirer side of this interface."""
 
+    model_config = ConfigDict(strict=True, populate_by_name=True)
+
     subject: str = Field(
         description="The subject name access requested by the requirer",
         examples=["subject-1"],
@@ -96,7 +108,7 @@ class KarapaceRequirerData(BaseModel):
     entity_permissions: str | None = Field(
         None,
         alias="entity-permissions",
-        description="List of permissions to assign to the custom entity, in JSON format",
+        description="List of permissions to assign to the custom entity, in JSON format. Written to the databag as an opaque string",
         examples=[
             "[{\"resource_name\": \"schemas\", \"resource_type\": \"SUBJECT\", \"privileges\": [\"READ\"]}]"
         ],
@@ -105,7 +117,10 @@ class KarapaceRequirerData(BaseModel):
 
     @field_validator("extra_user_roles", mode="before")
     @classmethod
-    def extra_user_roles_validator(cls, value: str) -> str:
+    def extra_user_roles_validator(cls, value: str | None) -> str | None:
+        if value is None:
+            return value
+
         try:
             _role = ExtraUserRole(value)
         except ValueError:
@@ -114,13 +129,5 @@ def extra_user_roles_validator(cls, value: str) -> str:
         return value
 
 
-class ProviderSchema(DataBagSchema):
-    """The schema for the provider side of this interface."""
-
-    app: KarapaceProviderData
-
-
-class RequirerSchema(DataBagSchema):
-    """The schema for the requirer side of this interface."""
-
-    app: KarapaceRequirerData
+ProviderUnitData = None
+RequirerUnitData = None