Source code for presto_hook

# -*- coding: utf-8 -*-
#
# Licensed 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
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# http://www.apache.org/licenses/LICENSE-2.0
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# Unless required by applicable law or agreed to in writing, software
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from builtins import str
import logging

from pyhive import presto
from pyhive.exc import DatabaseError

from airflow.hooks.dbapi_hook import DbApiHook

logging.getLogger("pyhive").setLevel(logging.INFO)


class PrestoException(Exception):
    pass


[docs]class PrestoHook(DbApiHook): """ Interact with Presto through PyHive! >>> ph = PrestoHook() >>> sql = "SELECT count(1) AS num FROM airflow.static_babynames" >>> ph.get_records(sql) [[340698]] """ conn_name_attr = 'presto_conn_id' default_conn_name = 'presto_default'
[docs] def get_conn(self): """Returns a connection object""" db = self.get_connection(self.presto_conn_id) return presto.connect( host=db.host, port=db.port, username=db.login, catalog=db.extra_dejson.get('catalog', 'hive'), schema=db.schema)
@staticmethod def _strip_sql(sql): return sql.strip().rstrip(';')
[docs] def get_records(self, hql, parameters=None): """ Get a set of records from Presto """ try: return super(PrestoHook, self).get_records( self._strip_sql(hql), parameters) except DatabaseError as e: if (hasattr(e, 'message') and 'errorName' in e.message and 'message' in e.message): # Use the structured error data in the raised exception raise PrestoException('{name}: {message}'.format( name=e.message['errorName'], message=e.message['message'])) else: raise PrestoException(str(e))
[docs] def get_first(self, hql, parameters=None): """ Returns only the first row, regardless of how many rows the query returns. """ try: return super(PrestoHook, self).get_first( self._strip_sql(hql), parameters) except DatabaseError as e: raise PrestoException(e[0]['message'])
[docs] def get_pandas_df(self, hql, parameters=None): """ Get a pandas dataframe from a sql query. """ import pandas cursor = self.get_cursor() try: cursor.execute(self._strip_sql(hql), parameters) data = cursor.fetchall() except DatabaseError as e: raise PrestoException(e[0]['message']) column_descriptions = cursor.description if data: df = pandas.DataFrame(data) df.columns = [c[0] for c in column_descriptions] else: df = pandas.DataFrame() return df
[docs] def run(self, hql, parameters=None): """ Execute the statement against Presto. Can be used to create views. """ return super(PrestoHook, self).run(self._strip_sql(hql), parameters)
def insert_rows(self): raise NotImplementedError()