superset2/superset/mcp_service/database/tool/list_databases.py

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# to you under the Apache License, Version 2.0 (the
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"""
List databases FastMCP tool (Advanced with metadata cache control)

This module contains the FastMCP tool for listing databases using
advanced filtering with clear, unambiguous request schema and metadata cache control.
"""

import logging
from typing import TYPE_CHECKING

from fastmcp import Context
from superset_core.mcp.decorators import tool, ToolAnnotations

if TYPE_CHECKING:
    from superset.models.core import Database

from superset.extensions import event_logger
from superset.mcp_service.database.schemas import (
    DatabaseError,
    DatabaseFilter,
    DatabaseInfo,
    DatabaseList,
    ListDatabasesRequest,
    serialize_database_object,
)
from superset.mcp_service.mcp_core import ModelListCore
from superset.mcp_service.privacy import (
    DATA_MODEL_METADATA_ERROR_TYPE,
    requires_data_model_metadata_access,
    user_can_view_data_model_metadata,
)

logger = logging.getLogger(__name__)

_DEFAULT_LIST_DATABASES_REQUEST = ListDatabasesRequest()


@tool(
    tags=["core"],
    class_permission_name="Database",
    annotations=ToolAnnotations(
        title="List databases",
        readOnlyHint=True,
        destructiveHint=False,
    ),
)
@requires_data_model_metadata_access
async def list_databases(
    request: ListDatabasesRequest | None = None,
    ctx: Context | None = None,
) -> DatabaseList | DatabaseError:
    """List database connections with filtering and search.

    Returns database metadata including name, backend type, and permissions.

    Sortable columns for order_column: id, database_name, changed_on,
    created_on
    """
    if ctx is None:
        raise RuntimeError("FastMCP context is required for list_databases")

    request = request or _DEFAULT_LIST_DATABASES_REQUEST.model_copy(deep=True)

    await ctx.info(
        "Listing databases: page=%s, page_size=%s, search=%s"
        % (
            request.page,
            request.page_size,
            request.search,
        )
    )
    await ctx.debug(
        "Database listing parameters: filters=%s, order_column=%s, "
        "order_direction=%s, select_columns=%s"
        % (
            request.filters,
            request.order_column,
            request.order_direction,
            request.select_columns,
        )
    )
    await ctx.debug(
        "Metadata cache settings: use_cache=%s, refresh_metadata=%s, force_refresh=%s"
        % (
            request.use_cache,
            request.refresh_metadata,
            request.force_refresh,
        )
    )

    if not user_can_view_data_model_metadata():
        await ctx.warning("Database listing blocked by data-model privacy controls")
        return DatabaseError.create(
            error="You don't have permission to access database details for your role.",
            error_type=DATA_MODEL_METADATA_ERROR_TYPE,
        )

    try:
        from superset.daos.database import DatabaseDAO
        from superset.mcp_service.common.schema_discovery import (
            DATABASE_DEFAULT_COLUMNS,
            DATABASE_SORTABLE_COLUMNS,
            get_all_column_names,
            get_database_columns,
        )

        # Get all column names dynamically from the model
        all_columns = get_all_column_names(get_database_columns())

        def _serialize_database(
            obj: "Database | None", cols: list[str] | None
        ) -> DatabaseInfo | None:
            """Serialize database (filtering via model_serializer)."""
            return serialize_database_object(obj)

        # Create tool with standard serialization
        list_tool = ModelListCore(
            dao_class=DatabaseDAO,
            output_schema=DatabaseInfo,
            item_serializer=_serialize_database,
            filter_type=DatabaseFilter,
            default_columns=DATABASE_DEFAULT_COLUMNS,
            search_columns=["database_name"],
            list_field_name="databases",
            output_list_schema=DatabaseList,
            all_columns=all_columns,
            sortable_columns=DATABASE_SORTABLE_COLUMNS,
            logger=logger,
        )

        with event_logger.log_context(action="mcp.list_databases.query"):
            result = list_tool.run_tool(
                filters=request.filters,
                search=request.search,
                select_columns=request.select_columns,
                order_column=request.order_column,
                order_direction=request.order_direction,
                page=max(request.page - 1, 0),
                page_size=request.page_size,
                created_by_me=request.created_by_me,
            )

        await ctx.info(
            "Databases listed successfully: count=%s, total_count=%s, total_pages=%s"
            % (
                len(result.databases) if hasattr(result, "databases") else 0,
                getattr(result, "total_count", None),
                getattr(result, "total_pages", None),
            )
        )

        # Apply field filtering via serialization context
        columns_to_filter = result.columns_requested
        await ctx.debug(
            "Applying field filtering via serialization context: columns=%s"
            % (columns_to_filter,)
        )
        with event_logger.log_context(action="mcp.list_databases.serialization"):
            return result.model_dump(
                mode="json",
                context={"select_columns": columns_to_filter},
            )

    except Exception as e:
        await ctx.error(
            "Database listing failed: page=%s, page_size=%s, error=%s, error_type=%s"
            % (
                request.page,
                request.page_size,
                str(e),
                type(e).__name__,
            )
        )
        raise