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# regarding copyright ownership. The ASF licenses this file
# to you under the Apache License, Version 2.0 (the
# "License"); you may not use this file except in compliance
# with the License. You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing,
# software distributed under the License is distributed on an
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# KIND, either express or implied. See the License for the
# specific language governing permissions and limitations
# under the License.
from __future__ import annotations
import json
import os
from typing import Any, Callable, Iterable, Mapping
import prestodb
from prestodb.exceptions import DatabaseError
from prestodb.transaction import IsolationLevel
from airflow import AirflowException
from airflow.configuration import conf
from airflow.models import Connection
from airflow.providers.common.sql.hooks.sql import DbApiHook
from airflow.utils.operator_helpers import AIRFLOW_VAR_NAME_FORMAT_MAPPING, DEFAULT_FORMAT_PREFIX
[docs]def generate_presto_client_info() -> str:
"""Return json string with dag_id, task_id, execution_date and try_number"""
context_var = {
format_map["default"].replace(DEFAULT_FORMAT_PREFIX, ""): os.environ.get(
format_map["env_var_format"], ""
)
for format_map in AIRFLOW_VAR_NAME_FORMAT_MAPPING.values()
}
task_info = {
"dag_id": context_var["dag_id"],
"task_id": context_var["task_id"],
"execution_date": context_var["execution_date"],
"try_number": context_var["try_number"],
"dag_run_id": context_var["dag_run_id"],
"dag_owner": context_var["dag_owner"],
}
return json.dumps(task_info, sort_keys=True)
[docs]class PrestoException(Exception):
"""Presto exception"""
def _boolify(value):
if isinstance(value, bool):
return value
if isinstance(value, str):
if value.lower() == "false":
return False
elif value.lower() == "true":
return True
return value
[docs]class PrestoHook(DbApiHook):
"""
Interact with Presto through prestodb.
>>> ph = PrestoHook()
>>> sql = "SELECT count(1) AS num FROM airflow.static_babynames"
>>> ph.get_records(sql)
[[340698]]
"""
[docs] conn_name_attr = "presto_conn_id"
[docs] default_conn_name = "presto_default"
[docs] def get_conn(self) -> Connection:
"""Returns a connection object"""
db = self.get_connection(self.presto_conn_id) # type: ignore[attr-defined]
extra = db.extra_dejson
auth = None
if db.password and extra.get("auth") == "kerberos":
raise AirflowException("Kerberos authorization doesn't support password.")
elif db.password:
auth = prestodb.auth.BasicAuthentication(db.login, db.password)
elif extra.get("auth") == "kerberos":
auth = prestodb.auth.KerberosAuthentication(
config=extra.get("kerberos__config", os.environ.get("KRB5_CONFIG")),
service_name=extra.get("kerberos__service_name"),
mutual_authentication=_boolify(extra.get("kerberos__mutual_authentication", False)),
force_preemptive=_boolify(extra.get("kerberos__force_preemptive", False)),
hostname_override=extra.get("kerberos__hostname_override"),
sanitize_mutual_error_response=_boolify(
extra.get("kerberos__sanitize_mutual_error_response", True)
),
principal=extra.get("kerberos__principal", conf.get("kerberos", "principal")),
delegate=_boolify(extra.get("kerberos__delegate", False)),
ca_bundle=extra.get("kerberos__ca_bundle"),
)
http_headers = {"X-Presto-Client-Info": generate_presto_client_info()}
presto_conn = prestodb.dbapi.connect(
host=db.host,
port=db.port,
user=db.login,
source=db.extra_dejson.get("source", "airflow"),
http_headers=http_headers,
http_scheme=db.extra_dejson.get("protocol", "http"),
catalog=db.extra_dejson.get("catalog", "hive"),
schema=db.schema,
auth=auth,
isolation_level=self.get_isolation_level(), # type: ignore[func-returns-value]
)
if extra.get("verify") is not None:
# Unfortunately verify parameter is available via public API.
# The PR is merged in the presto library, but has not been released.
# See: https://github.com/prestosql/presto-python-client/pull/31
presto_conn._http_session.verify = _boolify(extra["verify"])
return presto_conn
[docs] def get_isolation_level(self) -> Any:
"""Returns an isolation level"""
db = self.get_connection(self.presto_conn_id) # type: ignore[attr-defined]
isolation_level = db.extra_dejson.get("isolation_level", "AUTOCOMMIT").upper()
return getattr(IsolationLevel, isolation_level, IsolationLevel.AUTOCOMMIT)
[docs] def get_records(
self,
sql: str | list[str] = "",
parameters: Iterable | Mapping | None = None,
) -> Any:
if not isinstance(sql, str):
raise ValueError(f"The sql in Presto Hook must be a string and is {sql}!")
try:
return super().get_records(self.strip_sql_string(sql), parameters)
except DatabaseError as e:
raise PrestoException(e)
[docs] def get_first(self, sql: str | list[str] = "", parameters: Iterable | Mapping | None = None) -> Any:
if not isinstance(sql, str):
raise ValueError(f"The sql in Presto Hook must be a string and is {sql}!")
try:
return super().get_first(self.strip_sql_string(sql), parameters)
except DatabaseError as e:
raise PrestoException(e)
[docs] def get_pandas_df(self, sql: str = "", parameters=None, **kwargs):
import pandas
cursor = self.get_cursor()
try:
cursor.execute(self.strip_sql_string(sql), parameters)
data = cursor.fetchall()
except DatabaseError as e:
raise PrestoException(e)
column_descriptions = cursor.description
if data:
df = pandas.DataFrame(data, **kwargs)
df.columns = [c[0] for c in column_descriptions]
else:
df = pandas.DataFrame(**kwargs)
return df
[docs] def run(
self,
sql: str | Iterable[str],
autocommit: bool = False,
parameters: Iterable | Mapping | None = None,
handler: Callable | None = None,
split_statements: bool = False,
return_last: bool = True,
) -> Any | list[Any] | None:
return super().run(
sql=sql,
autocommit=autocommit,
parameters=parameters,
handler=handler,
split_statements=split_statements,
return_last=return_last,
)
[docs] def insert_rows(
self,
table: str,
rows: Iterable[tuple],
target_fields: Iterable[str] | None = None,
commit_every: int = 0,
replace: bool = False,
**kwargs,
) -> None:
"""
A generic way to insert a set of tuples into a table.
:param table: Name of the target table
:param rows: The rows to insert into the table
:param target_fields: The names of the columns to fill in the table
:param commit_every: The maximum number of rows to insert in one
transaction. Set to 0 to insert all rows in one transaction.
:param replace: Whether to replace instead of insert
"""
if self.get_isolation_level() == IsolationLevel.AUTOCOMMIT:
self.log.info(
"Transactions are not enable in presto connection. "
"Please use the isolation_level property to enable it. "
"Falling back to insert all rows in one transaction."
)
commit_every = 0
super().insert_rows(table, rows, target_fields, commit_every)
@staticmethod
def _serialize_cell(cell: Any, conn: Connection | None = None) -> Any:
"""
Presto will adapt all arguments to the execute() method internally,
hence we return cell without any conversion.
:param cell: The cell to insert into the table
:param conn: The database connection
:return: The cell
"""
return cell
