superset/db_engine_specs/snowflake.py

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# to you under the Apache License, Version 2.0 (the
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#
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# KIND, either express or implied.  See the License for the
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import json
import re
from datetime import datetime
from typing import Any, Dict, Optional, Pattern, Tuple, TYPE_CHECKING
from urllib import parse

from flask_babel import gettext as __
from sqlalchemy.engine.url import URL

from superset.db_engine_specs.postgres import PostgresBaseEngineSpec
from superset.errors import SupersetErrorType
from superset.models.sql_lab import Query
from superset.utils import core as utils

if TYPE_CHECKING:
    from superset.models.core import Database

# Regular expressions to catch custom errors
OBJECT_DOES_NOT_EXIST_REGEX = re.compile(
    r"Object (?P<object>.*?) does not exist or not authorized."
)

SYNTAX_ERROR_REGEX = re.compile(
    "syntax error line (?P<line>.+?) at position (?P<position>.+?) "
    "unexpected '(?P<syntax_error>.+?)'."
)


class SnowflakeEngineSpec(PostgresBaseEngineSpec):
    engine = "snowflake"
    engine_name = "Snowflake"
    force_column_alias_quotes = True
    max_column_name_length = 256

    _time_grain_expressions = {
        None: "{col}",
        "PT1S": "DATE_TRUNC('SECOND', {col})",
        "PT1M": "DATE_TRUNC('MINUTE', {col})",
        "PT5M": "DATEADD(MINUTE, FLOOR(DATE_PART(MINUTE, {col}) / 5) * 5, \
                DATE_TRUNC('HOUR', {col}))",
        "PT10M": "DATEADD(MINUTE, FLOOR(DATE_PART(MINUTE, {col}) / 10) * 10, \
                 DATE_TRUNC('HOUR', {col}))",
        "PT15M": "DATEADD(MINUTE, FLOOR(DATE_PART(MINUTE, {col}) / 15) * 15, \
                 DATE_TRUNC('HOUR', {col}))",
        "PT0.5H": "DATEADD(MINUTE, FLOOR(DATE_PART(MINUTE, {col}) / 30) * 30, \
                  DATE_TRUNC('HOUR', {col}))",
        "PT1H": "DATE_TRUNC('HOUR', {col})",
        "P1D": "DATE_TRUNC('DAY', {col})",
        "P1W": "DATE_TRUNC('WEEK', {col})",
        "P1M": "DATE_TRUNC('MONTH', {col})",
        "P0.25Y": "DATE_TRUNC('QUARTER', {col})",
        "P1Y": "DATE_TRUNC('YEAR', {col})",
    }

    custom_errors: Dict[Pattern[str], Tuple[str, SupersetErrorType, Dict[str, Any]]] = {
        OBJECT_DOES_NOT_EXIST_REGEX: (
            __("%(object)s does not exist in this database."),
            SupersetErrorType.OBJECT_DOES_NOT_EXIST_ERROR,
            {},
        ),
        SYNTAX_ERROR_REGEX: (
            __(
                "Please check your query for syntax errors at or "
                'near "%(syntax_error)s". Then, try running your query again.'
            ),
            SupersetErrorType.SYNTAX_ERROR,
            {},
        ),
    }

    @classmethod
    def adjust_database_uri(
        cls, uri: URL, selected_schema: Optional[str] = None
    ) -> None:
        database = uri.database
        if "/" in uri.database:
            database = uri.database.split("/")[0]
        if selected_schema:
            selected_schema = parse.quote(selected_schema, safe="")
            uri.database = database + "/" + selected_schema

    @classmethod
    def epoch_to_dttm(cls) -> str:
        return "DATEADD(S, {col}, '1970-01-01')"

    @classmethod
    def epoch_ms_to_dttm(cls) -> str:
        return "DATEADD(MS, {col}, '1970-01-01')"

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

    @staticmethod
    def mutate_db_for_connection_test(database: "Database") -> None:
        """
        By default, snowflake doesn't validate if the user/role has access to the chosen
        database.

        :param database: instance to be mutated
        """
        extra = json.loads(database.extra or "{}")
        engine_params = extra.get("engine_params", {})
        connect_args = engine_params.get("connect_args", {})
        connect_args["validate_default_parameters"] = True
        engine_params["connect_args"] = connect_args
        extra["engine_params"] = engine_params
        database.extra = json.dumps(extra)

    @classmethod
    def get_cancel_query_id(cls, cursor: Any, query: Query) -> Optional[str]:
        """
        Get Snowflake session ID that will be used to cancel all other running
        queries in the same session.

        :param cursor: Cursor instance in which the query will be executed
        :param query: Query instance
        :return: Snowflake Session ID
        """
        cursor.execute("SELECT CURRENT_SESSION()")
        row = cursor.fetchone()
        return row[0]

    @classmethod
    def cancel_query(cls, cursor: Any, query: Query, cancel_query_id: str) -> bool:
        """
        Cancel query in the underlying database.

        :param cursor: New cursor instance to the db of the query
        :param query: Query instance
        :param cancel_query_id: Snowflake Session ID
        :return: True if query cancelled successfully, False otherwise
        """
        try:
            cursor.execute(f"SELECT SYSTEM$CANCEL_ALL_QUERIES({cancel_query_id})")
        except Exception:  # pylint: disable=broad-except
            return False

        return True