[FLINK-14018][python] Add Python building blocks to make sure the bas…

…ic functionality of Python ScalarFunction could work

With this commit, users can write end to end python Table Api jobs with python UDFs. This commit mainly includes the
Api, rule optimization and python runtime changes.

.gitignore

@@ -35,6 +35,8 @@ flink-python/dev/download
 flink-python/dev/.conda/
 flink-python/dev/log/
 flink-python/dev/.stage.txt
+flink-python/.eggs/
+flink-python/pyflink/fn_execution/*_pb2.py
 atlassian-ide-plugin.xml
 out/
 /docs/api

flink-python/pom.xml

@@ -327,6 +327,26 @@ under the License.
 					</execution>
 				</executions>
 			</plugin>
+			<plugin>
+				<artifactId>exec-maven-plugin</artifactId>
+				<groupId>org.codehaus.mojo</groupId>
+				<version>1.5.0</version>
+				<executions>
+					<execution>
+						<id>Protos Generation</id>
+						<phase>generate-sources</phase>
+						<goals>
+							<goal>exec</goal>
+						</goals>
+						<configuration>
+							<executable>python</executable>
+							<arguments>
+								<argument>${basedir}/pyflink/gen_protos.py</argument>
+							</arguments>
+						</configuration>
+					</execution>
+				</executions>
+			</plugin>
 		</plugins>
 	</build>
 </project>

flink-python/pyflink/fn_execution/boot.py

@@ -145,5 +145,5 @@ def check_not_empty(check_str, error_message):
 if "FLINK_BOOT_TESTING" in os.environ and os.environ["FLINK_BOOT_TESTING"] == "1":
     exit(0)
 
-call([sys.executable, "-m", "apache_beam.runners.worker.sdk_worker_main"],
+call([sys.executable, "-m", "pyflink.fn_execution.sdk_worker_main"],
      stdout=sys.stdout, stderr=sys.stderr, env=env)

flink-python/pyflink/fn_execution/coder_impl.py

@@ -0,0 +1,80 @@
+################################################################################
+#  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.
+################################################################################
+import sys
+
+from apache_beam.coders.coder_impl import StreamCoderImpl
+
+if sys.version > '3':
+    xrange = range
+
+
+class RowCoderImpl(StreamCoderImpl):
+
+    def __init__(self, field_coders):
+        self._field_coders = field_coders
+
+    def encode_to_stream(self, value, out_stream, nested):
+        self.write_null_mask(value, out_stream)
+        for i in xrange(len(self._field_coders)):
+            self._field_coders[i].encode_to_stream(value[i], out_stream, nested)
+
+    def decode_from_stream(self, in_stream, nested):
+        from pyflink.table import Row
+        null_mask = self.read_null_mask(len(self._field_coders), in_stream)
+        assert len(null_mask) == len(self._field_coders)
+        return Row(*[None if null_mask[idx] else self._field_coders[idx].decode_from_stream(
+            in_stream, nested) for idx in xrange(0, len(null_mask))])
+
+    @staticmethod
+    def write_null_mask(value, out_stream):
+        field_pos = 0
+        field_count = len(value)
+        while field_pos < field_count:
+            b = 0x00
+            # set bits in byte
+            num_pos = min(8, field_count - field_pos)
+            byte_pos = 0
+            while byte_pos < num_pos:
+                b = b << 1
+                # set bit if field is null
+                if value[field_pos + byte_pos] is None:
+                    b |= 0x01
+                byte_pos += 1
+            field_pos += num_pos
+            # shift bits if last byte is not completely filled
+            b <<= (8 - byte_pos)
+            # write byte
+            out_stream.write_byte(b)
+
+    @staticmethod
+    def read_null_mask(field_count, in_stream):
+        null_mask = []
+        field_pos = 0
+        while field_pos < field_count:
+            b = in_stream.read_byte()
+            num_pos = min(8, field_count - field_pos)
+            byte_pos = 0
+            while byte_pos < num_pos:
+                null_mask.append((b & 0x80) > 0)
+                b = b << 1
+                byte_pos += 1
+            field_pos += num_pos
+        return null_mask
+
+    def __repr__(self):
+        return 'RowCoderImpl[%s]' % ', '.join(str(c) for c in self._field_coders)

flink-python/pyflink/fn_execution/coders.py

@@ -0,0 +1,86 @@
+################################################################################
+#  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.
+################################################################################
+import sys
+
+from apache_beam.coders import Coder, VarIntCoder
+from apache_beam.coders.coders import FastCoder
+
+from pyflink.fn_execution import coder_impl
+from pyflink.fn_execution import flink_fn_execution_pb2
+
+FLINK_SCHEMA_CODER_URN = "flink:coder:schema:v1"
+
+if sys.version > '3':
+    xrange = range
+
+
+__all__ = ['RowCoder']
+
+
+class RowCoder(FastCoder):
+    """
+    Coder for Row.
+    """
+
+    def __init__(self, field_coders):
+        self._field_coders = field_coders
+
+    def _create_impl(self):
+        return coder_impl.RowCoderImpl([c.get_impl() for c in self._field_coders])
+
+    def is_deterministic(self):
+        return all(c.is_deterministic() for c in self._field_coders)
+
+    def to_type_hint(self):
+        from pyflink.table import Row
+        return Row
+
+    def __repr__(self):
+        return 'RowCoder[%s]' % ', '.join(str(c) for c in self._field_coders)
+
+    def __eq__(self, other):
+        return (self.__class__ == other.__class__
+                and len(self._field_coders) == len(other._field_coders)
+                and [self._field_coders[i] == other._field_coders[i] for i in
+                     xrange(len(self._field_coders))])
+
+    def __ne__(self, other):
+        return not self == other
+
+    def __hash__(self):
+        return hash(self._field_coders)
+
+
+@Coder.register_urn(FLINK_SCHEMA_CODER_URN, flink_fn_execution_pb2.Schema)
+def _pickle_from_runner_api_parameter(schema_proto, unused_components, unused_context):
+    return RowCoder([from_proto(f.type) for f in schema_proto.fields])
+
+
+def from_proto(field_type):
+    """
+    Creates the corresponding :class:`Coder` given the protocol representation of the field type.
+
+    :param field_type: the protocol representation of the field type
+    :return: :class:`Coder`
+    """
+    if field_type.type_name == flink_fn_execution_pb2.Schema.TypeName.BIGINT:
+        return VarIntCoder()
+    elif field_type.type_name == flink_fn_execution_pb2.Schema.TypeName.ROW:
+        return RowCoder([from_proto(f.type) for f in field_type.row_schema.fields])
+    else:
+        raise ValueError("field_type %s is not supported." % field_type)