#
# Licensed to the Apache Software Foundation (ASF) under one or more
# contributor license agreements. See the NOTICE file distributed with
# this work for additional information 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 "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
#
"""
User-defined function related classes and functions
"""
import functools
from pyspark import SparkContext, since
from pyspark.rdd import _prepare_for_python_RDD, PythonEvalType, ignore_unicode_prefix
from pyspark.sql.column import Column, _to_java_column, _to_seq
from pyspark.sql.types import StringType, DataType, StructType, _parse_datatype_string, \
to_arrow_type, to_arrow_schema
__all__ = ["UDFRegistration"]
def _wrap_function(sc, func, returnType):
command = (func, returnType)
pickled_command, broadcast_vars, env, includes = _prepare_for_python_RDD(sc, command)
return sc._jvm.PythonFunction(bytearray(pickled_command), env, includes, sc.pythonExec,
sc.pythonVer, broadcast_vars, sc._javaAccumulator)
def _create_udf(f, returnType, evalType):
if evalType in (PythonEvalType.SQL_SCALAR_PANDAS_UDF,
PythonEvalType.SQL_GROUPED_MAP_PANDAS_UDF):
import inspect
from pyspark.sql.utils import require_minimum_pyarrow_version
require_minimum_pyarrow_version()
argspec = inspect.getargspec(f)
if evalType == PythonEvalType.SQL_SCALAR_PANDAS_UDF and len(argspec.args) == 0 and \
argspec.varargs is None:
raise ValueError(
"Invalid function: 0-arg pandas_udfs are not supported. "
"Instead, create a 1-arg pandas_udf and ignore the arg in your function."
)
if evalType == PythonEvalType.SQL_GROUPED_MAP_PANDAS_UDF and len(argspec.args) != 1:
raise ValueError(
"Invalid function: pandas_udfs with function type GROUPED_MAP "
"must take a single arg that is a pandas DataFrame."
)
# Set the name of the UserDefinedFunction object to be the name of function f
udf_obj = UserDefinedFunction(
f, returnType=returnType, name=None, evalType=evalType, deterministic=True)
return udf_obj._wrapped()
class UserDefinedFunction(object):
"""
User defined function in Python
.. versionadded:: 1.3
"""
def __init__(self, func,
returnType=StringType(),
name=None,
evalType=PythonEvalType.SQL_BATCHED_UDF,
deterministic=True):
if not callable(func):
raise TypeError(
"Invalid function: not a function or callable (__call__ is not defined): "
"{0}".format(type(func)))
if not isinstance(returnType, (DataType, str)):
raise TypeError(
"Invalid returnType: returnType should be DataType or str "
"but is {}".format(returnType))
if not isinstance(evalType, int):
raise TypeError(
"Invalid evalType: evalType should be an int but is {}".format(evalType))
self.func = func
self._returnType = returnType
# Stores UserDefinedPythonFunctions jobj, once initialized
self._returnType_placeholder = None
self._judf_placeholder = None
self._name = name or (
func.__name__ if hasattr(func, '__name__')
else func.__class__.__name__)
self.evalType = evalType
self.deterministic = deterministic
@property
def returnType(self):
# This makes sure this is called after SparkContext is initialized.
# ``_parse_datatype_string`` accesses to JVM for parsing a DDL formatted string.
if self._returnType_placeholder is None:
if isinstance(self._returnType, DataType):
self._returnType_placeholder = self._returnType
else:
self._returnType_placeholder = _parse_datatype_string(self._returnType)
if self.evalType == PythonEvalType.SQL_SCALAR_PANDAS_UDF:
try:
to_arrow_type(self._returnType_placeholder)
except TypeError:
raise NotImplementedError(
"Invalid returnType with scalar Pandas UDFs: %s is "
"not supported" % str(self._returnType_placeholder))
elif self.evalType == PythonEvalType.SQL_GROUPED_MAP_PANDAS_UDF:
if isinstance(self._returnType_placeholder, StructType):
try:
to_arrow_schema(self._returnType_placeholder)
except TypeError:
raise NotImplementedError(
"Invalid returnType with grouped map Pandas UDFs: "
"%s is not supported" % str(self._returnType_placeholder))
else:
raise TypeError("Invalid returnType for grouped map Pandas "
"UDFs: returnType must be a StructType.")
return self._returnType_placeholder
@property
def _judf(self):
# It is possible that concurrent access, to newly created UDF,
# will initialize multiple UserDefinedPythonFunctions.
# This is unlikely, doesn't affect correctness,
# and should have a minimal performance impact.
if self._judf_placeholder is None:
self._judf_placeholder = self._create_judf()
return self._judf_placeholder
def _create_judf(self):
from pyspark.sql import SparkSession
spark = SparkSession.builder.getOrCreate()
sc = spark.sparkContext
wrapped_func = _wrap_function(sc, self.func, self.returnType)
jdt = spark._jsparkSession.parseDataType(self.returnType.json())
judf = sc._jvm.org.apache.spark.sql.execution.python.UserDefinedPythonFunction(
self._name, wrapped_func, jdt, self.evalType, self.deterministic)
return judf
def __call__(self, *cols):
judf = self._judf
sc = SparkContext._active_spark_context
return Column(judf.apply(_to_seq(sc, cols, _to_java_column)))
# This function is for improving the online help system in the interactive interpreter.
# For example, the built-in help / pydoc.help. It wraps the UDF with the docstring and
# argument annotation. (See: SPARK-19161)
def _wrapped(self):
"""
Wrap this udf with a function and attach docstring from func
"""
# It is possible for a callable instance without __name__ attribute or/and
# __module__ attribute to be wrapped here. For example, functools.partial. In this case,
# we should avoid wrapping the attributes from the wrapped function to the wrapper
# function. So, we take out these attribute names from the default names to set and
# then manually assign it after being wrapped.
assignments = tuple(
a for a in functools.WRAPPER_ASSIGNMENTS if a != '__name__' and a != '__module__')
@functools.wraps(self.func, assigned=assignments)
def wrapper(*args):
return self(*args)
wrapper.__name__ = self._name
wrapper.__module__ = (self.func.__module__ if hasattr(self.func, '__module__')
else self.func.__class__.__module__)
wrapper.func = self.func
wrapper.returnType = self.returnType
wrapper.evalType = self.evalType
wrapper.deterministic = self.deterministic
wrapper.asNondeterministic = functools.wraps(
self.asNondeterministic)(lambda: self.asNondeterministic()._wrapped())
return wrapper
def asNondeterministic(self):
"""
Updates UserDefinedFunction to nondeterministic.
.. versionadded:: 2.3
"""
# Here, we explicitly clean the cache to create a JVM UDF instance
# with 'deterministic' updated. See SPARK-23233.
self._judf_placeholder = None
self.deterministic = False
return self
[docs]class UDFRegistration(object):
"""
Wrapper for user-defined function registration. This instance can be accessed by
:attr:`spark.udf` or :attr:`sqlContext.udf`.
.. versionadded:: 1.3.1
"""
def __init__(self, sparkSession):
self.sparkSession = sparkSession
[docs] @ignore_unicode_prefix
@since("1.3.1")
def register(self, name, f, returnType=None):
"""Register a Python function (including lambda function) or a user-defined function
as a SQL function.
:param name: name of the user-defined function in SQL statements.
:param f: a Python function, or a user-defined function. The user-defined function can
be either row-at-a-time or vectorized. See :meth:`pyspark.sql.functions.udf` and
:meth:`pyspark.sql.functions.pandas_udf`.
:param returnType: the return type of the registered user-defined function. The value can
be either a :class:`pyspark.sql.types.DataType` object or a DDL-formatted type string.
:return: a user-defined function.
To register a nondeterministic Python function, users need to first build
a nondeterministic user-defined function for the Python function and then register it
as a SQL function.
`returnType` can be optionally specified when `f` is a Python function but not
when `f` is a user-defined function. Please see below.
1. When `f` is a Python function:
`returnType` defaults to string type and can be optionally specified. The produced
object must match the specified type. In this case, this API works as if
`register(name, f, returnType=StringType())`.
>>> strlen = spark.udf.register("stringLengthString", lambda x: len(x))
>>> spark.sql("SELECT stringLengthString('test')").collect()
[Row(stringLengthString(test)=u'4')]
>>> spark.sql("SELECT 'foo' AS text").select(strlen("text")).collect()
[Row(stringLengthString(text)=u'3')]
>>> from pyspark.sql.types import IntegerType
>>> _ = spark.udf.register("stringLengthInt", lambda x: len(x), IntegerType())
>>> spark.sql("SELECT stringLengthInt('test')").collect()
[Row(stringLengthInt(test)=4)]
>>> from pyspark.sql.types import IntegerType
>>> _ = spark.udf.register("stringLengthInt", lambda x: len(x), IntegerType())
>>> spark.sql("SELECT stringLengthInt('test')").collect()
[Row(stringLengthInt(test)=4)]
2. When `f` is a user-defined function:
Spark uses the return type of the given user-defined function as the return type of
the registered user-defined function. `returnType` should not be specified.
In this case, this API works as if `register(name, f)`.
>>> from pyspark.sql.types import IntegerType
>>> from pyspark.sql.functions import udf
>>> slen = udf(lambda s: len(s), IntegerType())
>>> _ = spark.udf.register("slen", slen)
>>> spark.sql("SELECT slen('test')").collect()
[Row(slen(test)=4)]
>>> import random
>>> from pyspark.sql.functions import udf
>>> from pyspark.sql.types import IntegerType
>>> random_udf = udf(lambda: random.randint(0, 100), IntegerType()).asNondeterministic()
>>> new_random_udf = spark.udf.register("random_udf", random_udf)
>>> spark.sql("SELECT random_udf()").collect() # doctest: +SKIP
[Row(random_udf()=82)]
>>> from pyspark.sql.functions import pandas_udf, PandasUDFType
>>> @pandas_udf("integer", PandasUDFType.SCALAR) # doctest: +SKIP
... def add_one(x):
... return x + 1
...
>>> _ = spark.udf.register("add_one", add_one) # doctest: +SKIP
>>> spark.sql("SELECT add_one(id) FROM range(3)").collect() # doctest: +SKIP
[Row(add_one(id)=1), Row(add_one(id)=2), Row(add_one(id)=3)]
.. note:: Registration for a user-defined function (case 2.) was added from
Spark 2.3.0.
"""
# This is to check whether the input function is from a user-defined function or
# Python function.
if hasattr(f, 'asNondeterministic'):
if returnType is not None:
raise TypeError(
"Invalid returnType: data type can not be specified when f is"
"a user-defined function, but got %s." % returnType)
if f.evalType not in [PythonEvalType.SQL_BATCHED_UDF,
PythonEvalType.SQL_SCALAR_PANDAS_UDF]:
raise ValueError(
"Invalid f: f must be either SQL_BATCHED_UDF or SQL_SCALAR_PANDAS_UDF")
register_udf = UserDefinedFunction(f.func, returnType=f.returnType, name=name,
evalType=f.evalType,
deterministic=f.deterministic)
return_udf = f
else:
if returnType is None:
returnType = StringType()
register_udf = UserDefinedFunction(f, returnType=returnType, name=name,
evalType=PythonEvalType.SQL_BATCHED_UDF)
return_udf = register_udf._wrapped()
self.sparkSession._jsparkSession.udf().registerPython(name, register_udf._judf)
return return_udf
[docs] @ignore_unicode_prefix
@since(2.3)
def registerJavaFunction(self, name, javaClassName, returnType=None):
"""Register a Java user-defined function as a SQL function.
In addition to a name and the function itself, the return type can be optionally specified.
When the return type is not specified we would infer it via reflection.
:param name: name of the user-defined function
:param javaClassName: fully qualified name of java class
:param returnType: the return type of the registered Java function. The value can be either
a :class:`pyspark.sql.types.DataType` object or a DDL-formatted type string.
>>> from pyspark.sql.types import IntegerType
>>> spark.udf.registerJavaFunction(
... "javaStringLength", "test.org.apache.spark.sql.JavaStringLength", IntegerType())
>>> spark.sql("SELECT javaStringLength('test')").collect()
[Row(UDF:javaStringLength(test)=4)]
>>> spark.udf.registerJavaFunction(
... "javaStringLength2", "test.org.apache.spark.sql.JavaStringLength")
>>> spark.sql("SELECT javaStringLength2('test')").collect()
[Row(UDF:javaStringLength2(test)=4)]
>>> spark.udf.registerJavaFunction(
... "javaStringLength3", "test.org.apache.spark.sql.JavaStringLength", "integer")
>>> spark.sql("SELECT javaStringLength3('test')").collect()
[Row(UDF:javaStringLength3(test)=4)]
"""
jdt = None
if returnType is not None:
if not isinstance(returnType, DataType):
returnType = _parse_datatype_string(returnType)
jdt = self.sparkSession._jsparkSession.parseDataType(returnType.json())
self.sparkSession._jsparkSession.udf().registerJava(name, javaClassName, jdt)
[docs] @ignore_unicode_prefix
@since(2.3)
def registerJavaUDAF(self, name, javaClassName):
"""Register a Java user-defined aggregate function as a SQL function.
:param name: name of the user-defined aggregate function
:param javaClassName: fully qualified name of java class
>>> spark.udf.registerJavaUDAF("javaUDAF", "test.org.apache.spark.sql.MyDoubleAvg")
>>> df = spark.createDataFrame([(1, "a"),(2, "b"), (3, "a")],["id", "name"])
>>> df.createOrReplaceTempView("df")
>>> spark.sql("SELECT name, javaUDAF(id) as avg from df group by name").collect()
[Row(name=u'b', avg=102.0), Row(name=u'a', avg=102.0)]
"""
self.sparkSession._jsparkSession.udf().registerJavaUDAF(name, javaClassName)
def _test():
import doctest
from pyspark.sql import SparkSession
import pyspark.sql.udf
globs = pyspark.sql.udf.__dict__.copy()
spark = SparkSession.builder\
.master("local[4]")\
.appName("sql.udf tests")\
.getOrCreate()
globs['spark'] = spark
(failure_count, test_count) = doctest.testmod(
pyspark.sql.udf, globs=globs,
optionflags=doctest.ELLIPSIS | doctest.NORMALIZE_WHITESPACE)
spark.stop()
if failure_count:
exit(-1)
if __name__ == "__main__":
_test()
