superset/db_engine_specs/druid.py

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

from sqlalchemy import types
from sqlalchemy.engine.reflection import Inspector

from superset import is_feature_enabled
from superset.db_engine_specs.base import BaseEngineSpec
from superset.exceptions import SupersetException
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):
    """Engine spec for Druid.io"""

    engine = "druid"
    engine_name = "Apache Druid"
    allows_joins = is_feature_enabled("DRUID_JOINS")
    allows_subqueries = True

    _time_grain_expressions = {
        None: "{col}",
        "PT1S": "TIME_FLOOR(CAST({col} AS TIMESTAMP), 'PT1S')",
        "PT5S": "TIME_FLOOR(CAST({col} AS TIMESTAMP), 'PT5S')",
        "PT30S": "TIME_FLOOR(CAST({col} AS TIMESTAMP), 'PT30S')",
        "PT1M": "TIME_FLOOR(CAST({col} AS TIMESTAMP), 'PT1M')",
        "PT5M": "TIME_FLOOR(CAST({col} AS TIMESTAMP), 'PT5M')",
        "PT10M": "TIME_FLOOR(CAST({col} AS TIMESTAMP), 'PT10M')",
        "PT15M": "TIME_FLOOR(CAST({col} AS TIMESTAMP), 'PT15M')",
        "PT30M": "TIME_FLOOR(CAST({col} AS TIMESTAMP), 'PT30M')",
        "PT1H": "TIME_FLOOR(CAST({col} AS TIMESTAMP), 'PT1H')",
        "PT6H": "TIME_FLOOR(CAST({col} AS TIMESTAMP), 'PT6H')",
        "P1D": "TIME_FLOOR(CAST({col} AS TIMESTAMP), 'P1D')",
        "P1W": "TIME_FLOOR(CAST({col} AS TIMESTAMP), 'P1W')",
        "P1M": "TIME_FLOOR(CAST({col} AS TIMESTAMP), 'P1M')",
        "P3M": "TIME_FLOOR(CAST({col} AS TIMESTAMP), 'P3M')",
        "P1Y": "TIME_FLOOR(CAST({col} AS TIMESTAMP), 'P1Y')",
        "P1W/1970-01-03T00:00:00Z": (
            "TIME_SHIFT(TIME_FLOOR(TIME_SHIFT(CAST({col} AS TIMESTAMP), "
            "'P1D', 1), 'P1W'), 'P1D', 5)"
        ),
        "1969-12-28T00:00:00Z/P1W": (
            "TIME_SHIFT(TIME_FLOOR(TIME_SHIFT(CAST({col} AS TIMESTAMP), "
            "'P1D', 1), 'P1W'), 'P1D', -1)"
        ),
    }

    @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
        :raises SupersetException: If database extra json payload is unparseable
        """
        try:
            extra = json.loads(database.extra or "{}")
        except json.JSONDecodeError as ex:
            raise SupersetException("Unable to parse database extras") from 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, db_extra: Optional[Dict[str, Any]] = None
    ) -> 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

    @classmethod
    def epoch_to_dttm(cls) -> str:
        """
        Convert from number of seconds since the epoch to a timestamp.
        """
        return "MILLIS_TO_TIMESTAMP({col} * 1000)"

    @classmethod
    def epoch_ms_to_dttm(cls) -> str:
        """
        Convert from number of milliseconds since the epoch to a timestamp.
        """
        return "MILLIS_TO_TIMESTAMP({col})"

    @classmethod
    def get_columns(
        cls, inspector: Inspector, table_name: str, schema: Optional[str]
    ) -> List[Dict[str, Any]]:
        """
        Update the Druid type map.
        """
        # pylint: disable=import-outside-toplevel
        from pydruid.db.sqlalchemy import type_map

        type_map["complex<hllsketch>"] = types.BLOB

        return super().get_columns(inspector, table_name, schema)