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"""This module contains an operator to move data from an S3 bucket to Hive."""
from __future__ import annotations
import bz2
import gzip
import os
import tempfile
from tempfile import NamedTemporaryFile, TemporaryDirectory
from typing import TYPE_CHECKING, Any, Sequence
from airflow.exceptions import AirflowException
from airflow.models import BaseOperator
from airflow.providers.amazon.aws.hooks.s3 import S3Hook
from airflow.providers.apache.hive.hooks.hive import HiveCliHook
from airflow.utils.compression import uncompress_file
if TYPE_CHECKING:
from airflow.utils.context import Context
[docs]class S3ToHiveOperator(BaseOperator):
"""
Moves data from S3 to Hive.
The operator downloads a file from S3, stores the file locally
before loading it into a Hive table.
If the ``create`` or ``recreate`` arguments are set to ``True``,
a ``CREATE TABLE`` and ``DROP TABLE`` statements are generated.
Hive data types are inferred from the cursor's metadata from.
Note that the table generated in Hive uses ``STORED AS textfile``
which isn't the most efficient serialization format. If a
large amount of data is loaded and/or if the tables gets
queried considerably, you may want to use this operator only to
stage the data into a temporary table before loading it into its
final destination using a ``HiveOperator``.
:param s3_key: The key to be retrieved from S3. (templated)
:param field_dict: A dictionary of the fields name in the file
as keys and their Hive types as values
:param hive_table: target Hive table, use dot notation to target a
specific database. (templated)
:param delimiter: field delimiter in the file
:param create: whether to create the table if it doesn't exist
:param recreate: whether to drop and recreate the table at every
execution
:param partition: target partition as a dict of partition columns
and values. (templated)
:param headers: whether the file contains column names on the first
line
:param check_headers: whether the column names on the first line should be
checked against the keys of field_dict
:param wildcard_match: whether the s3_key should be interpreted as a Unix
wildcard pattern
:param aws_conn_id: source s3 connection
:param verify: Whether or not to verify SSL certificates for S3 connection.
By default SSL certificates are verified.
You can provide the following values:
- ``False``: do not validate SSL certificates. SSL will still be used
(unless use_ssl is False), but SSL certificates will not be
verified.
- ``path/to/cert/bundle.pem``: A filename of the CA cert bundle to uses.
You can specify this argument if you want to use a different
CA cert bundle than the one used by botocore.
:param hive_cli_conn_id: Reference to the
:ref:`Hive CLI connection id <howto/connection:hive_cli>`.
:param input_compressed: Boolean to determine if file decompression is
required to process headers
:param tblproperties: TBLPROPERTIES of the hive table being created
:param select_expression: S3 Select expression
"""
[docs] template_fields: Sequence[str] = ("s3_key", "partition", "hive_table")
[docs] template_ext: Sequence[str] = ()
def __init__(
self,
*,
s3_key: str,
field_dict: dict,
hive_table: str,
delimiter: str = ",",
create: bool = True,
recreate: bool = False,
partition: dict | None = None,
headers: bool = False,
check_headers: bool = False,
wildcard_match: bool = False,
aws_conn_id: str | None = "aws_default",
verify: bool | str | None = None,
hive_cli_conn_id: str = "hive_cli_default",
input_compressed: bool = False,
tblproperties: dict | None = None,
select_expression: str | None = None,
hive_auth: str | None = None,
**kwargs,
) -> None:
super().__init__(**kwargs)
self.s3_key = s3_key
self.field_dict = field_dict
self.hive_table = hive_table
self.delimiter = delimiter
self.create = create
self.recreate = recreate
self.partition = partition
self.headers = headers
self.check_headers = check_headers
self.wildcard_match = wildcard_match
self.hive_cli_conn_id = hive_cli_conn_id
self.aws_conn_id = aws_conn_id
self.verify = verify
self.input_compressed = input_compressed
self.tblproperties = tblproperties
self.select_expression = select_expression
self.hive_auth = hive_auth
if self.check_headers and not (self.field_dict is not None and self.headers):
raise AirflowException("To check_headers provide field_dict and headers")
[docs] def execute(self, context: Context):
# Downloading file from S3
s3_hook = S3Hook(aws_conn_id=self.aws_conn_id, verify=self.verify)
hive_hook = HiveCliHook(hive_cli_conn_id=self.hive_cli_conn_id, auth=self.hive_auth)
self.log.info("Downloading S3 file")
if self.wildcard_match:
if not s3_hook.check_for_wildcard_key(self.s3_key):
raise AirflowException(f"No key matches {self.s3_key}")
s3_key_object = s3_hook.get_wildcard_key(self.s3_key)
elif s3_hook.check_for_key(self.s3_key):
s3_key_object = s3_hook.get_key(self.s3_key)
else:
raise AirflowException(f"The key {self.s3_key} does not exists")
if TYPE_CHECKING:
assert s3_key_object
_, file_ext = os.path.splitext(s3_key_object.key)
if self.select_expression and self.input_compressed and file_ext.lower() != ".gz":
raise AirflowException("GZIP is the only compression format Amazon S3 Select supports")
with TemporaryDirectory(prefix="tmps32hive_") as tmp_dir, NamedTemporaryFile(
mode="wb", dir=tmp_dir, suffix=file_ext
) as f:
self.log.info("Dumping S3 key %s contents to local file %s", s3_key_object.key, f.name)
if self.select_expression:
option = {}
if self.headers:
option["FileHeaderInfo"] = "USE"
if self.delimiter:
option["FieldDelimiter"] = self.delimiter
input_serialization: dict[str, Any] = {"CSV": option}
if self.input_compressed:
input_serialization["CompressionType"] = "GZIP"
content = s3_hook.select_key(
bucket_name=s3_key_object.bucket_name,
key=s3_key_object.key,
expression=self.select_expression,
input_serialization=input_serialization,
)
f.write(content.encode("utf-8"))
else:
s3_key_object.download_fileobj(f)
f.flush()
if self.select_expression or not self.headers:
self.log.info("Loading file %s into Hive", f.name)
hive_hook.load_file(
f.name,
self.hive_table,
field_dict=self.field_dict,
create=self.create,
partition=self.partition,
delimiter=self.delimiter,
recreate=self.recreate,
tblproperties=self.tblproperties,
)
else:
# Decompressing file
if self.input_compressed:
self.log.info("Uncompressing file %s", f.name)
fn_uncompressed = uncompress_file(f.name, file_ext, tmp_dir)
self.log.info("Uncompressed to %s", fn_uncompressed)
# uncompressed file available now so deleting
# compressed file to save disk space
f.close()
else:
fn_uncompressed = f.name
# Testing if header matches field_dict
if self.check_headers:
self.log.info("Matching file header against field_dict")
header_list = self._get_top_row_as_list(fn_uncompressed)
if not self._match_headers(header_list):
raise AirflowException("Header check failed")
# Deleting top header row
self.log.info("Removing header from file %s", fn_uncompressed)
headless_file = self._delete_top_row_and_compress(fn_uncompressed, file_ext, tmp_dir)
self.log.info("Headless file %s", headless_file)
self.log.info("Loading file %s into Hive", headless_file)
hive_hook.load_file(
headless_file,
self.hive_table,
field_dict=self.field_dict,
create=self.create,
partition=self.partition,
delimiter=self.delimiter,
recreate=self.recreate,
tblproperties=self.tblproperties,
)
def _get_top_row_as_list(self, file_name):
with open(file_name) as file:
header_line = file.readline().strip()
return header_line.split(self.delimiter)
def _match_headers(self, header_list):
if not header_list:
raise AirflowException("Unable to retrieve header row from file")
field_names = self.field_dict.keys()
if len(field_names) != len(header_list):
self.log.warning(
"Headers count mismatch File headers:\n %s\nField names: \n %s\n", header_list, field_names
)
return False
test_field_match = all(h1.lower() == h2.lower() for h1, h2 in zip(header_list, field_names))
if test_field_match:
return True
else:
self.log.warning(
"Headers do not match field names File headers:\n %s\nField names: \n %s\n",
header_list,
field_names,
)
return False
@staticmethod
def _delete_top_row_and_compress(input_file_name, output_file_ext, dest_dir):
# When output_file_ext is not defined, file is not compressed
open_fn = open
if output_file_ext.lower() == ".gz":
open_fn = gzip.GzipFile
elif output_file_ext.lower() == ".bz2":
open_fn = bz2.BZ2File
_, fn_output = tempfile.mkstemp(suffix=output_file_ext, dir=dest_dir)
with open(input_file_name, "rb") as f_in, open_fn(fn_output, "wb") as f_out:
f_in.seek(0)
next(f_in)
for line in f_in:
f_out.write(line)
return fn_output