superset/db_engine_specs/druid.py

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import json
import logging
from datetime import datetime
from typing import Any, Dict, Optional, TYPE_CHECKING

from superset.db_engine_specs.base import BaseEngineSpec
from superset.utils import core as utils

if TYPE_CHECKING:
    from superset.connectors.sqla.models import TableColumn
    from superset.models.core import Database

logger = logging.getLogger()


class DruidEngineSpec(BaseEngineSpec):  # pylint: disable=abstract-method
    """Engine spec for Druid.io"""

    engine = "druid"
    engine_name = "Apache Druid"
    allows_joins = False
    allows_subqueries = True

    _time_grain_expressions = {
        None: "{col}",
        "PT1S": "FLOOR({col} TO SECOND)",
        "PT1M": "FLOOR({col} TO MINUTE)",
        "PT5M": "TIME_FLOOR({col}, 'PT5M')",
        "PT10M": "TIME_FLOOR({col}, 'PT10M')",
        "PT15M": "TIME_FLOOR({col}, 'PT15M')",
        "PT0.5H": "TIME_FLOOR({col}, 'PT30M')",
        "PT1H": "FLOOR({col} TO HOUR)",
        "P1D": "FLOOR({col} TO DAY)",
        "P1W": "FLOOR({col} TO WEEK)",
        "P1M": "FLOOR({col} TO MONTH)",
        "P0.25Y": "FLOOR({col} TO QUARTER)",
        "P1Y": "FLOOR({col} TO YEAR)",
    }

    @classmethod
    def alter_new_orm_column(cls, orm_col: "TableColumn") -> None:
        if orm_col.column_name == "__time":
            orm_col.is_dttm = True

    @staticmethod
    def get_extra_params(database: "Database") -> Dict[str, Any]:
        """
        For Druid, the path to a SSL certificate is placed in `connect_args`.

        :param database: database instance from which to extract extras
        :raises CertificateException: If certificate is not valid/unparseable
        """
        try:
            extra = json.loads(database.extra or "{}")
        except json.JSONDecodeError as ex:
            logger.error(ex)
            raise ex

        if database.server_cert:
            engine_params = extra.get("engine_params", {})
            connect_args = engine_params.get("connect_args", {})
            connect_args["scheme"] = "https"
            path = utils.create_ssl_cert_file(database.server_cert)
            connect_args["ssl_verify_cert"] = path
            engine_params["connect_args"] = connect_args
            extra["engine_params"] = engine_params
        return extra

    @classmethod
    def convert_dttm(cls, target_type: str, dttm: datetime) -> Optional[str]:
        tt = target_type.upper()
        if tt == utils.TemporalType.DATE:
            return f"CAST(TIME_PARSE('{dttm.date().isoformat()}') AS DATE)"
        if tt in (utils.TemporalType.DATETIME, utils.TemporalType.TIMESTAMP):
            return f"""TIME_PARSE('{dttm.isoformat(timespec="seconds")}')"""
        return None