[SPARK-4897] [PySpark] Python 3 support

This PR update PySpark to support Python 3 (tested with 3.4).

Known issue: unpickle array from Pyrolite is broken in Python 3, those tests are skipped.

TODO: ec2/spark-ec2.py is not fully tested with python3.

Author: Davies Liu <davies@databricks.com>
Author: twneale <twneale@gmail.com>
Author: Josh Rosen <joshrosen@databricks.com>

Closes #5173 from davies/python3 and squashes the following commits:

d7d6323 [Davies Liu] fix tests
6c52a98 [Davies Liu] fix mllib test
99e334f [Davies Liu] update timeout
b716610 [Davies Liu] Merge branch 'master' of github.com:apache/spark into python3
cafd5ec [Davies Liu] adddress comments from @mengxr
bf225d7 [Davies Liu] Merge branch 'master' of github.com:apache/spark into python3
179fc8d [Davies Liu] tuning flaky tests
8c8b957 [Davies Liu] fix ResourceWarning in Python 3
5c57c95 [Davies Liu] Merge branch 'master' of github.com:apache/spark into python3
4006829 [Davies Liu] fix test
2fc0066 [Davies Liu] add python3 path
71535e9 [Davies Liu] fix xrange and divide
5a55ab4 [Davies Liu] Merge branch 'master' of github.com:apache/spark into python3
125f12c [Davies Liu] Merge branch 'master' of github.com:apache/spark into python3
ed498c8 [Davies Liu] fix compatibility with python 3
820e649 [Davies Liu] Merge branch 'master' of github.com:apache/spark into python3
e8ce8c9 [Davies Liu] Merge branch 'master' of github.com:apache/spark into python3
ad7c374 [Davies Liu] fix mllib test and warning
ef1fc2f [Davies Liu] fix tests
4eee14a [Davies Liu] Merge branch 'master' of github.com:apache/spark into python3
20112ff [Davies Liu] Merge branch 'master' of github.com:apache/spark into python3
59bb492 [Davies Liu] fix tests
1da268c [Davies Liu] Merge branch 'master' of github.com:apache/spark into python3
ca0fdd3 [Davies Liu] fix code style
9563a15 [Davies Liu] add imap back for python 2
0b1ec04 [Davies Liu] make python examples work with Python 3
d2fd566 [Davies Liu] Merge branch 'master' of github.com:apache/spark into python3
a716d34 [Davies Liu] test with python 3.4
f1700e8 [Davies Liu] fix test in python3
671b1db [Davies Liu] fix test in python3
692ff47 [Davies Liu] fix flaky test
7b9699f [Davies Liu] invalidate import cache for Python 3.3+
9c58497 [Davies Liu] fix kill worker
309bfbf [Davies Liu] keep compatibility
5707476 [Davies Liu] cleanup, fix hash of string in 3.3+
8662d5b [Davies Liu] Merge branch 'master' of github.com:apache/spark into python3
f53e1f0 [Davies Liu] fix tests
70b6b73 [Davies Liu] compile ec2/spark_ec2.py in python 3
a39167e [Davies Liu] support customize class in __main__
814c77b [Davies Liu] run unittests with python 3
7f4476e [Davies Liu] mllib tests passed
d737924 [Davies Liu] pass ml tests
375ea17 [Davies Liu] SQL tests pass
6cc42a9 [Davies Liu] rename
431a8de [Davies Liu] streaming tests pass
78901a7 [Davies Liu] fix hash of serializer in Python 3
24b2f2e [Davies Liu] pass all RDD tests
35f48fe [Davies Liu] run future again
1eebac2 [Davies Liu] fix conflict in ec2/spark_ec2.py
6e3c21d [Davies Liu] make cloudpickle work with Python3
2fb2db3 [Josh Rosen] Guard more changes behind sys.version; still doesn't run
1aa5e8f [twneale] Turned out `pickle.DictionaryType is dict` == True, so swapped it out
7354371 [twneale] buffer --> memoryview  I'm not super sure if this a valid change, but the 2.7 docs recommend using memoryview over buffer where possible, so hoping it'll work.
b69ccdf [twneale] Uses the pure python pickle._Pickler instead of c-extension _pickle.Pickler. It appears pyspark 2.7 uses the pure python pickler as well, so this shouldn't degrade pickling performance (?).
f40d925 [twneale] xrange --> range
e104215 [twneale] Replaces 2.7 types.InstsanceType with 3.4 `object`....could be horribly wrong depending on how types.InstanceType is used elsewhere in the package--see http://bugs.python.org/issue8206
79de9d0 [twneale] Replaces python2.7 `file` with 3.4 _io.TextIOWrapper
2adb42d [Josh Rosen] Fix up some import differences between Python 2 and 3
854be27 [Josh Rosen] Run `futurize` on Python code:
7c5b4ce [Josh Rosen] Remove Python 3 check in shell.py.

1 files changed, 20 insertions, 12 deletions

diff --git a/python/pyspark/sql/context.py b/python/pyspark/sql/context.py
index e8529a8f8e..c90afc326c 100644
--- a/python/pyspark/sql/context.py
+++ b/python/pyspark/sql/context.py
@@ -15,14 +15,19 @@
 # limitations under the License.
 #
 
+import sys
 import warnings
 import json
-from itertools import imap
+
+if sys.version >= '3':
+    basestring = unicode = str
+else:
+    from itertools import imap as map
 
 from py4j.protocol import Py4JError
 from py4j.java_collections import MapConverter
 
-from pyspark.rdd import RDD, _prepare_for_python_RDD
+from pyspark.rdd import RDD, _prepare_for_python_RDD, ignore_unicode_prefix
 from pyspark.serializers import AutoBatchedSerializer, PickleSerializer
 from pyspark.sql.types import Row, StringType, StructType, _verify_type, \
     _infer_schema, _has_nulltype, _merge_type, _create_converter, _python_to_sql_converter
@@ -62,31 +67,27 @@ class SQLContext(object):
     A SQLContext can be used create :class:`DataFrame`, register :class:`DataFrame` as
     tables, execute SQL over tables, cache tables, and read parquet files.
 
-    When created, :class:`SQLContext` adds a method called ``toDF`` to :class:`RDD`,
-    which could be used to convert an RDD into a DataFrame, it's a shorthand for
-    :func:`SQLContext.createDataFrame`.
-
     :param sparkContext: The :class:`SparkContext` backing this SQLContext.
     :param sqlContext: An optional JVM Scala SQLContext. If set, we do not instantiate a new
         SQLContext in the JVM, instead we make all calls to this object.
     """
 
+    @ignore_unicode_prefix
     def __init__(self, sparkContext, sqlContext=None):
         """Creates a new SQLContext.
 
         >>> from datetime import datetime
         >>> sqlContext = SQLContext(sc)
-        >>> allTypes = sc.parallelize([Row(i=1, s="string", d=1.0, l=1L,
+        >>> allTypes = sc.parallelize([Row(i=1, s="string", d=1.0, l=1,
         ...     b=True, list=[1, 2, 3], dict={"s": 0}, row=Row(a=1),
         ...     time=datetime(2014, 8, 1, 14, 1, 5))])
         >>> df = allTypes.toDF()
         >>> df.registerTempTable("allTypes")
         >>> sqlContext.sql('select i+1, d+1, not b, list[1], dict["s"], time, row.a '
         ...            'from allTypes where b and i > 0').collect()
-        [Row(c0=2, c1=2.0, c2=False, c3=2, c4=0...8, 1, 14, 1, 5), a=1)]
-        >>> df.map(lambda x: (x.i, x.s, x.d, x.l, x.b, x.time,
-        ...                     x.row.a, x.list)).collect()
-        [(1, u'string', 1.0, 1, True, ...(2014, 8, 1, 14, 1, 5), 1, [1, 2, 3])]
+        [Row(c0=2, c1=2.0, c2=False, c3=2, c4=0, time=datetime.datetime(2014, 8, 1, 14, 1, 5), a=1)]
+        >>> df.map(lambda x: (x.i, x.s, x.d, x.l, x.b, x.time, x.row.a, x.list)).collect()
+        [(1, u'string', 1.0, 1, True, datetime.datetime(2014, 8, 1, 14, 1, 5), 1, [1, 2, 3])]
         """
         self._sc = sparkContext
         self._jsc = self._sc._jsc
@@ -122,6 +123,7 @@ class SQLContext(object):
         """Returns a :class:`UDFRegistration` for UDF registration."""
         return UDFRegistration(self)
 
+    @ignore_unicode_prefix
     def registerFunction(self, name, f, returnType=StringType()):
         """Registers a lambda function as a UDF so it can be used in SQL statements.
 
@@ -147,7 +149,7 @@ class SQLContext(object):
         >>> sqlContext.sql("SELECT stringLengthInt('test')").collect()
         [Row(c0=4)]
         """
-        func = lambda _, it: imap(lambda x: f(*x), it)
+        func = lambda _, it: map(lambda x: f(*x), it)
         ser = AutoBatchedSerializer(PickleSerializer())
         command = (func, None, ser, ser)
         pickled_cmd, bvars, env, includes = _prepare_for_python_RDD(self._sc, command, self)
@@ -185,6 +187,7 @@ class SQLContext(object):
             schema = rdd.map(_infer_schema).reduce(_merge_type)
         return schema
 
+    @ignore_unicode_prefix
     def inferSchema(self, rdd, samplingRatio=None):
         """::note: Deprecated in 1.3, use :func:`createDataFrame` instead.
         """
@@ -195,6 +198,7 @@ class SQLContext(object):
 
         return self.createDataFrame(rdd, None, samplingRatio)
 
+    @ignore_unicode_prefix
     def applySchema(self, rdd, schema):
         """::note: Deprecated in 1.3, use :func:`createDataFrame` instead.
         """
@@ -208,6 +212,7 @@ class SQLContext(object):
 
         return self.createDataFrame(rdd, schema)
 
+    @ignore_unicode_prefix
     def createDataFrame(self, data, schema=None, samplingRatio=None):
         """
         Creates a :class:`DataFrame` from an :class:`RDD` of :class:`tuple`/:class:`list`,
@@ -380,6 +385,7 @@ class SQLContext(object):
             df = self._ssql_ctx.jsonFile(path, scala_datatype)
         return DataFrame(df, self)
 
+    @ignore_unicode_prefix
     def jsonRDD(self, rdd, schema=None, samplingRatio=1.0):
         """Loads an RDD storing one JSON object per string as a :class:`DataFrame`.
 
@@ -477,6 +483,7 @@ class SQLContext(object):
                                                     joptions)
         return DataFrame(df, self)
 
+    @ignore_unicode_prefix
     def sql(self, sqlQuery):
         """Returns a :class:`DataFrame` representing the result of the given query.
 
@@ -497,6 +504,7 @@ class SQLContext(object):
         """
         return DataFrame(self._ssql_ctx.table(tableName), self)
 
+    @ignore_unicode_prefix
     def tables(self, dbName=None):
         """Returns a :class:`DataFrame` containing names of tables in the given database.