[SPARK-3634] [PySpark] User's module should take precedence over syst…

…em modules

Python modules added through addPyFile should take precedence over system modules.

This patch put the path for user added module in the front of sys.path (just after '').

Author: Davies Liu <[email protected]>

Closes apache#2492 from davies/path and squashes the following commits:

4a2af78 [Davies Liu] fix tests
f7ff4da [Davies Liu] ad license header
6b0002f [Davies Liu] add tests
c16c392 [Davies Liu] put addPyFile in front of sys.path

python/pyspark/context.py

@@ -171,7 +171,7 @@ def _do_init(self, master, appName, sparkHome, pyFiles, environment, batchSize,
 
         SparkFiles._sc = self
         root_dir = SparkFiles.getRootDirectory()
-        sys.path.append(root_dir)
+        sys.path.insert(1, root_dir)
 
         # Deploy any code dependencies specified in the constructor
         self._python_includes = list()
@@ -183,10 +183,9 @@ def _do_init(self, master, appName, sparkHome, pyFiles, environment, batchSize,
         for path in self._conf.get("spark.submit.pyFiles", "").split(","):
             if path != "":
                 (dirname, filename) = os.path.split(path)
-                self._python_includes.append(filename)
-                sys.path.append(path)
-                if dirname not in sys.path:
-                    sys.path.append(dirname)
+                if filename.lower().endswith("zip") or filename.lower().endswith("egg"):
+                    self._python_includes.append(filename)
+                    sys.path.insert(1, os.path.join(SparkFiles.getRootDirectory(), filename))
 
         # Create a temporary directory inside spark.local.dir:
         local_dir = self._jvm.org.apache.spark.util.Utils.getLocalDir(self._jsc.sc().conf())
@@ -667,7 +666,7 @@ def addPyFile(self, path):
         if filename.endswith('.zip') or filename.endswith('.ZIP') or filename.endswith('.egg'):
             self._python_includes.append(filename)
             # for tests in local mode
-            sys.path.append(os.path.join(SparkFiles.getRootDirectory(), filename))
+            sys.path.insert(1, os.path.join(SparkFiles.getRootDirectory(), filename))
 
     def setCheckpointDir(self, dirName):
         """

python/pyspark/tests.py

@@ -323,6 +323,18 @@ def func():
         from userlib import UserClass
         self.assertEqual("Hello World from inside a package!", UserClass().hello())
 
+    def test_overwrite_system_module(self):
+        self.sc.addPyFile(os.path.join(SPARK_HOME, "python/test_support/SimpleHTTPServer.py"))
+
+        import SimpleHTTPServer
+        self.assertEqual("My Server", SimpleHTTPServer.__name__)
+
+        def func(x):
+            import SimpleHTTPServer
+            return SimpleHTTPServer.__name__
+
+        self.assertEqual(["My Server"], self.sc.parallelize(range(1)).map(func).collect())
+
 
 class TestRDDFunctions(PySparkTestCase):
 

python/pyspark/worker.py

@@ -43,6 +43,13 @@ def report_times(outfile, boot, init, finish):
     write_long(1000 * finish, outfile)
 
 
+def add_path(path):
+    # worker can be used, so donot add path multiple times
+    if path not in sys.path:
+        # overwrite system packages
+        sys.path.insert(1, path)
+
+
 def main(infile, outfile):
     try:
         boot_time = time.time()
@@ -61,11 +68,11 @@ def main(infile, outfile):
         SparkFiles._is_running_on_worker = True
 
         # fetch names of includes (*.zip and *.egg files) and construct PYTHONPATH
-        sys.path.append(spark_files_dir)  # *.py files that were added will be copied here
+        add_path(spark_files_dir)  # *.py files that were added will be copied here
         num_python_includes = read_int(infile)
         for _ in range(num_python_includes):
             filename = utf8_deserializer.loads(infile)
-            sys.path.append(os.path.join(spark_files_dir, filename))
+            add_path(os.path.join(spark_files_dir, filename))
 
         # fetch names and values of broadcast variables
         num_broadcast_variables = read_int(infile)

python/test_support/SimpleHTTPServer.py

@@ -0,0 +1,22 @@
+#
+# 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.
+#
+
+"""
+Used to test override standard SimpleHTTPServer module.
+"""
+
+__name__ = "My Server"