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from airflow.contrib.hooks.aws_hook import AwsHook
[docs]class AwsGlueCatalogHook(AwsHook):
"""
Interact with AWS Glue Catalog
:param aws_conn_id: ID of the Airflow connection where
credentials and extra configuration are stored
:type aws_conn_id: str
:param region_name: aws region name (example: us-east-1)
:type region_name: str
"""
def __init__(self,
aws_conn_id='aws_default',
region_name=None,
*args,
**kwargs):
self.region_name = region_name
super(AwsGlueCatalogHook, self).__init__(aws_conn_id=aws_conn_id, *args, **kwargs)
[docs] def get_conn(self):
"""
Returns glue connection object.
"""
self.conn = self.get_client_type('glue', self.region_name)
return self.conn
[docs] def get_partitions(self,
database_name,
table_name,
expression='',
page_size=None,
max_items=None):
"""
Retrieves the partition values for a table.
:param database_name: The name of the catalog database where the partitions reside.
:type database_name: str
:param table_name: The name of the partitions' table.
:type table_name: str
:param expression: An expression filtering the partitions to be returned.
Please see official AWS documentation for further information.
https://docs.aws.amazon.com/glue/latest/dg/aws-glue-api-catalog-partitions.html#aws-glue-api-catalog-partitions-GetPartitions
:type expression: str
:param page_size: pagination size
:type page_size: int
:param max_items: maximum items to return
:type max_items: int
:return: set of partition values where each value is a tuple since
a partition may be composed of multiple columns. For example:
``{('2018-01-01','1'), ('2018-01-01','2')}``
"""
config = {
'PageSize': page_size,
'MaxItems': max_items,
}
paginator = self.get_conn().get_paginator('get_partitions')
response = paginator.paginate(
DatabaseName=database_name,
TableName=table_name,
Expression=expression,
PaginationConfig=config
)
partitions = set()
for page in response:
for p in page['Partitions']:
partitions.add(tuple(p['Values']))
return partitions
[docs] def check_for_partition(self, database_name, table_name, expression):
"""
Checks whether a partition exists
:param database_name: Name of hive database (schema) @table belongs to
:type database_name: str
:param table_name: Name of hive table @partition belongs to
:type table_name: str
:expression: Expression that matches the partitions to check for
(eg `a = 'b' AND c = 'd'`)
:type expression: str
:rtype: bool
>>> hook = AwsGlueCatalogHook()
>>> t = 'static_babynames_partitioned'
>>> hook.check_for_partition('airflow', t, "ds='2015-01-01'")
True
"""
partitions = self.get_partitions(database_name, table_name, expression, max_items=1)
if partitions:
return True
else:
return False
[docs] def get_table(self, database_name, table_name):
"""
Get the information of the table
:param database_name: Name of hive database (schema) @table belongs to
:type database_name: str
:param table_name: Name of hive table
:type table_name: str
:rtype: dict
>>> hook = AwsGlueCatalogHook()
>>> r = hook.get_table('db', 'table_foo')
>>> r['Name'] = 'table_foo'
"""
result = self.get_conn().get_table(DatabaseName=database_name, Name=table_name)
return result['Table']
[docs] def get_table_location(self, database_name, table_name):
"""
Get the physical location of the table
:param database_name: Name of hive database (schema) @table belongs to
:type database_name: str
:param table_name: Name of hive table
:type table_name: str
:return: str
"""
table = self.get_table(database_name, table_name)
return table['StorageDescriptor']['Location']