def create_table(table_name: str, schema_name: str, columns: dict,
partitions: dict, path: str, session_helper: SessionHelper):
"""
Creates a table in AWS redshift. The table will be named schema_name.table_name and belong to the (existing) Redshift db db_name.
Args:
table_name: name of created table. NOTE: THIS WILL ERROR IF table_name ALREADY EXISTS IN REDSHIFT
schema_name: name of schema in redshift. Schema must be external and already exist!
columns: Dictionary with keys corresponding to column names and values corresponding to pandas dtypes, excluding partition columns.
partitions: Dict similar to columns, except ONLY with partition columns
path: Path to published contract in s3 (excluding partitions)
session_helper: Instance of Redshift s3parq.session_helper
"""
_redshift_name_validator(table_name)
redshift_columns = _datatype_mapper(columns)
redshift_partitions = _datatype_mapper(partitions)
with session_helper.db_session_scope() as scope:
if_exists_query = f'SELECT EXISTS(SELECT schemaname, tablename FROM SVV_EXTERNAL_TABLES WHERE tablename=\'{table_name}\' AND schemaname=\'{schema_name}\');'
table_exists = scope.execute(if_exists_query).first()[0]
if table_exists: return
if not partitions:
new_schema_query = (
f'CREATE EXTERNAL TABLE {schema_name}.{table_name} {redshift_columns} \
STORED AS PARQUET \
LOCATION \'{path}\';')
else:
new_schema_query = (
f'CREATE EXTERNAL TABLE {schema_name}.{table_name} {redshift_columns} \
PARTITIONED BY {redshift_partitions} STORED AS PARQUET \
LOCATION \'{path}\';')
logger.info(f'Running query to create table: {new_schema_query}')
scope.execute(new_schema_query)
def create_partitions(bucket: str, schema: str, table: str, filepath: str,
session_helper: SessionHelper) -> str:
'''
Generates partitioning SQL
Args:
bucket (str): S3 bucket where data is stored
schema (str): name of redshift schema (must already exist)
table (str): name of table in schema. Must have partitions scoped out in `CREATE TABLE ...`
filepath (str): path to data in S3 that will be queryable by it's partitions
----
Returns:
query (str): a raw SQL string that adds the partitioned data to the table
--------
Example:
Args:
bucket = 'MyBucket'
schema = 'MySchema'
table = 'MyTable'
filepath = 'path/to/data/apple=abcd/banana=1234/abcd1234.parquet'
Returns:
"ALTER TABLE MySchema.MyTable ADD PARTITION (apple='abcd' ,banana='1234') LOCATION 's3://MyBucket/path/to/data/apple=abcd';"
'''
partitions = _get_partitions_for_spectrum(filepath)
formatted_partitions = _format_partition_strings_for_sql(partitions)
path_to_data = _get_partition_location(filepath)
with session_helper.db_session_scope() as scope:
partitions_query = f"ALTER TABLE {schema}.{table} \
ADD IF NOT EXISTS PARTITION ({', '.join(formatted_partitions)}) \
LOCATION 's3://{bucket}/{path_to_data}';"
logger.info(f'Running query to create: {partitions_query}')
scope.execute(partitions_query)
def create_partitions(bucket: str, schema: str, table: str, filepath: str, session_helper: SessionHelper) -> None:
''' Executes the SQL that creates partitions on the given table for an
individual file
Args:
bucket (str): S3 bucket where data is stored
schema (str): name of redshift schema (must already exist)
table (str): name of table in schema. Must have partitions scoped out in `CREATE TABLE ...`
filepath (str): path to data in S3 that will be queryable by it's partitions
NOTE: This is to the single parquet file, including the partitions
session_helper (SessionHelper): a configured s3parq.session_helper.SessionHelper session
Returns:
None
Example:
Args:
bucket = 'MyBucket'
schema = 'MySchema'
table = 'MyTable'
filepath = 'path/to/data/apple=abcd/banana=1234/abcd1234.parquet'
session_helper = some_configured_session
'''
partitions = _get_partitions_for_spectrum(filepath)
formatted_partitions = _format_partition_strings_for_sql(partitions)
path_to_data = _get_partition_location(filepath)
with session_helper.db_session_scope() as scope:
partitions_query = f"ALTER TABLE {schema}.{table} \
ADD IF NOT EXISTS PARTITION ({', '.join(formatted_partitions)}) \
LOCATION 's3://{bucket}/{path_to_data}';"
logger.info(f'Running query to create: {partitions_query}')
scope.execute(partitions_query)
def create_custom_table(table_name: str, schema_name: str, partitions: dict, path: str, custom_redshift_columns: dict, session_helper: SessionHelper) -> None:
""" Creates a table in AWS redshift. The table will be named
schema_name.table_name and belong to the (existing) Redshift db db_name.
The created table will use the CUSTOM redshift column data types defined
in custom_redshift_columns.
Args:
table_name (str): name of created table
NOTE: THIS WILL ERROR IF table_name ALREADY EXISTS IN REDSHIFT
schema_name (str): name of schema in redshift; Schema must be external
and already exist!
partitions (dict): Dict similar to columns, except ONLY with partition columns
path (str): Path to published dataset in s3 (excluding partitions)
custom_redshift_columns (dict):
This dictionary contains custom column data type definitions for redshift.
The params should be formatted as follows:
- column name (str)
- data type (str)
session_helper (SessionHelper): Instance of Redshift s3parq.session_helper
"""
logger.info("Running create_custom_table...")
_redshift_name_validator(table_name)
logger.info("Generating create columns sql statement with custom redshift columns...")
logger.info("Generating create partitions sql statement with custom redshift columns...")
redshift_columns_sql = ""
redshift_partitions_sql = ""
for k, v in custom_redshift_columns.items():
if k in partitions:
redshift_partitions_sql += f'{k} {v}, '
else:
redshift_columns_sql += f'{k} {v}, '
redshift_columns = f"({redshift_columns_sql[:-2]})" # Slice off the last space and comma
redshift_partitions = f"({redshift_partitions_sql[:-2]})" # Slice off the last space and comma
with session_helper.db_session_scope() as scope:
if_exists_query = f'SELECT EXISTS(SELECT schemaname, tablename FROM SVV_EXTERNAL_TABLES WHERE tablename=\'{table_name}\' AND schemaname=\'{schema_name}\');'
table_exists = scope.execute(if_exists_query).first()[0]
if table_exists:
return
if not partitions:
new_schema_query = (
f'CREATE EXTERNAL TABLE {schema_name}.{table_name} {redshift_columns} \
STORED AS PARQUET \
LOCATION \'{path}\';'
)
else:
new_schema_query = (
f'CREATE EXTERNAL TABLE {schema_name}.{table_name} {redshift_columns} \
PARTITIONED BY {redshift_partitions} STORED AS PARQUET \
LOCATION \'{path}\';'
)
logger.info(f'Running query to create table: {new_schema_query}')
scope.execute(new_schema_query)
def create_schema(schema_name: str, db_name: str, iam_role: str,
session_helper: SessionHelper):
"""Creates a schema in AWS redshift using a given iam_role. The schema is named schema_name and belongs to the (existing) Redshift db db_name.
iam_role is a link to an existing AWS IAM Role with Redshift Spectrum write permissions."""
_redshift_name_validator(schema_name, db_name)
with session_helper.db_session_scope() as scope:
new_schema_query = f"CREATE EXTERNAL SCHEMA IF NOT EXISTS {schema_name} \
FROM DATA CATALOG \
database '{db_name}' \
iam_role '{iam_role}';"
logger.info(f'Running query to create schema: {new_schema_query}')
scope.execute(new_schema_query)
def create_schema(schema_name: str, db_name: str, iam_role: str, session_helper: SessionHelper) -> None:
""" Creates a schema in AWS redshift using a given iam_role
Args:
schema_name (str): Name of the schema to create in Redshift Spectrum
db_name (str): (Existing) database that the schema should belong to
iam_role (str): link to an existing AWS IAM Role with Redshift Spectrum
write permissions
session_helper (str): Active and configured session_helper session to use
"""
_redshift_name_validator(schema_name, db_name)
with session_helper.db_session_scope() as scope:
new_schema_query = f"CREATE EXTERNAL SCHEMA IF NOT EXISTS {schema_name} \
FROM DATA CATALOG \
database '{db_name}' \
iam_role '{iam_role}';"
logger.info(f'Running query to create schema: {new_schema_query}')
scope.execute(new_schema_query)
def create_schema(schema_name: str, session_helper: SessionHelper):
schema_name_validator(schema_name)
with session_helper.db_session_scope() as scope:
scope.execute(f'CREATE SCHEMA IF NOT EXISTS {schema_name}')
