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# to you under the Apache License, Version 2.0 (the
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#
#   http://www.apache.org/licenses/LICENSE-2.0
#
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# KIND, either express or implied.  See the License for the
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import os
from typing import TYPE_CHECKING, Optional, Sequence

from airflow.models import BaseOperator
from airflow.providers.amazon.aws.hooks.s3 import S3Hook
from airflow.providers.mysql.hooks.mysql import MySqlHook

if TYPE_CHECKING:
    from airflow.utils.context import Context


class S3ToMySqlOperator(BaseOperator):
    """
    Loads a file from S3 into a MySQL table.

    :param s3_source_key: The path to the file (S3 key) that will be loaded into MySQL.
    :param mysql_table: The MySQL table into where the data will be sent.
    :param mysql_duplicate_key_handling: Specify what should happen to duplicate data.
        You can choose either `IGNORE` or `REPLACE`.

        .. seealso::
            https://dev.mysql.com/doc/refman/8.0/en/load-data.html#load-data-duplicate-key-handling
    :param mysql_extra_options: MySQL options to specify exactly how to load the data.
    :param aws_conn_id: The S3 connection that contains the credentials to the S3 Bucket.
    :param mysql_conn_id: Reference to :ref:`mysql connection id <howto/connection:mysql>`.
    """

    template_fields: Sequence[str] = (
        's3_source_key',
        'mysql_table',
    )
    template_ext: Sequence[str] = ()
    ui_color = '#f4a460'

    def __init__(
        self,
        *,
        s3_source_key: str,
        mysql_table: str,
        mysql_duplicate_key_handling: str = 'IGNORE',
        mysql_extra_options: Optional[str] = None,
        aws_conn_id: str = 'aws_default',
        mysql_conn_id: str = 'mysql_default',
        **kwargs,
    ) -> None:
        super().__init__(**kwargs)
        self.s3_source_key = s3_source_key
        self.mysql_table = mysql_table
        self.mysql_duplicate_key_handling = mysql_duplicate_key_handling
        self.mysql_extra_options = mysql_extra_options or ''
        self.aws_conn_id = aws_conn_id
        self.mysql_conn_id = mysql_conn_id

    def execute(self, context: 'Context') -> None:
        """
        Executes the transfer operation from S3 to MySQL.

        :param context: The context that is being provided when executing.
        """
        self.log.info('Loading %s to MySql table %s...', self.s3_source_key, self.mysql_table)

        s3_hook = S3Hook(aws_conn_id=self.aws_conn_id)
        file = s3_hook.download_file(key=self.s3_source_key)

        try:
            mysql = MySqlHook(mysql_conn_id=self.mysql_conn_id)
            mysql.bulk_load_custom(
                table=self.mysql_table,
                tmp_file=file,
                duplicate_key_handling=self.mysql_duplicate_key_handling,
                extra_options=self.mysql_extra_options,
            )
        finally:
            # Remove file downloaded from s3 to be idempotent.
            os.remove(file)
