core: add support for flexible versions

Varint code lifted from the java kafka repo, with the caveat that we
need to specify a byte size by bitmasking due to how python integers
handle the sign bit
Serialization tests lifted from java repo as well

- Add support for varints
- Add support for compact collections (byte array, string, array)
- Add support for new request and response headers, supporting flexible
versions
- Add flexible versions extraction script
- Add List / Alter partition reassignments apis

Author: Tincu Gabriel

kafka/protocol/__init__.py

@@ -43,4 +43,6 @@
     40: 'ExpireDelegationToken',
     41: 'DescribeDelegationToken',
     42: 'DeleteGroups',
+    45: 'AlterPartitionReassignments',
+    46: 'ListPartitionReassignments',
 }

kafka/protocol/admin.py

@@ -1,7 +1,7 @@
 from __future__ import absolute_import
 
 from kafka.protocol.api import Request, Response
-from kafka.protocol.types import Array, Boolean, Bytes, Int8, Int16, Int32, Int64, Schema, String
+from kafka.protocol.types import Array, Boolean, Bytes, Int8, Int16, Int32, Int64, Schema, String, CompactString, CompactArray, TaggedFields
 
 
 class ApiVersionResponse_v0(Response):
@@ -923,3 +923,92 @@ class DeleteGroupsRequest_v1(Request):
 DeleteGroupsResponse = [
     DeleteGroupsResponse_v0, DeleteGroupsResponse_v1
 ]
+
+
+class AlterPartitionReassignmentsResponse_v0(Response):
+    API_KEY = 45
+    API_VERSION = 0
+    SCHEMA = Schema(
+        ("throttle_time_ms", Int32),
+        ("error_code", Int16),
+        ("error_message", CompactString("utf-8")),
+        ("responses", CompactArray(
+            ("name", CompactString("utf-8")),
+            ("partitions", CompactArray(
+                ("partition_index", Int32),
+                ("error_code", Int16),
+                ("error_message", CompactString("utf-8")),
+                ("tags", TaggedFields)
+            )),
+            ("tags", TaggedFields)
+        )),
+        ("tags", TaggedFields)
+    )
+
+
+class AlterPartitionReassignmentsRequest_v0(Request):
+    FLEXIBLE_VERSION = True
+    API_KEY = 45
+    API_VERSION = 0
+    RESPONSE_TYPE = AlterPartitionReassignmentsResponse_v0
+    SCHEMA = Schema(
+        ("timeout_ms", Int32),
+        ("topics", CompactArray(
+            ("name", CompactString("utf-8")),
+            ("partitions", CompactArray(
+                ("partition_index", Int32),
+                ("replicas", CompactArray(Int32)),
+                ("tags", TaggedFields)
+            )),
+            ("tags", TaggedFields)
+        )),
+        ("tags", TaggedFields)
+    )
+
+
+AlterPartitionReassignmentsRequest = [AlterPartitionReassignmentsRequest_v0]
+
+AlterPartitionReassignmentsResponse = [AlterPartitionReassignmentsResponse_v0]
+
+
+class ListPartitionReassignmentsResponse_v0(Response):
+    API_KEY = 46
+    API_VERSION = 0
+    SCHEMA = Schema(
+        ("throttle_time_ms", Int32),
+        ("error_code", Int16),
+        ("error_message", CompactString("utf-8")),
+        ("topics", CompactArray(
+            ("name", CompactString("utf-8")),
+            ("partitions", CompactArray(
+                ("partition_index", Int32),
+                ("replicas", CompactArray(Int32)),
+                ("adding_replicas", CompactArray(Int32)),
+                ("removing_replicas", CompactArray(Int32)),
+                ("tags", TaggedFields)
+            )),
+            ("tags", TaggedFields)
+        )),
+        ("tags", TaggedFields)
+    )
+
+
+class ListPartitionReassignmentsRequest_v0(Request):
+    FLEXIBLE_VERSION = True
+    API_KEY = 46
+    API_VERSION = 0
+    RESPONSE_TYPE = ListPartitionReassignmentsResponse_v0
+    SCHEMA = Schema(
+        ("timeout_ms", Int32),
+        ("topics", CompactArray(
+            ("name", CompactString("utf-8")),
+            ("partition_index", CompactArray(Int32)),
+            ("tags", TaggedFields)
+        )),
+        ("tags", TaggedFields)
+    )
+
+
+ListPartitionReassignmentsRequest = [ListPartitionReassignmentsRequest_v0]
+
+ListPartitionReassignmentsResponse = [ListPartitionReassignmentsResponse_v0]

kafka/protocol/api.py

@@ -3,7 +3,7 @@
 import abc
 
 from kafka.protocol.struct import Struct
-from kafka.protocol.types import Int16, Int32, String, Schema, Array
+from kafka.protocol.types import Int16, Int32, String, Schema, Array, TaggedFields
 
 
 class RequestHeader(Struct):
@@ -20,9 +20,41 @@ def __init__(self, request, correlation_id=0, client_id='kafka-python'):
         )
 
 
+class RequestHeaderV2(Struct):
+    # Flexible response / request headers end in field buffer
+    SCHEMA = Schema(
+        ('api_key', Int16),
+        ('api_version', Int16),
+        ('correlation_id', Int32),
+        ('client_id', String('utf-8')),
+        ('_tag_buffer', TaggedFields)
+    )
+
+    def __init__(self, request, correlation_id=0, client_id='kafka-python', tags=None):
+        super(RequestHeaderV2, self).__init__(
+            request.API_KEY, request.API_VERSION, correlation_id, client_id, tags or {}
+        )
+
+
+class ResponseHeader(Struct):
+    SCHEMA = Schema(
+        ('correlation_id', Int32),
+    )
+
+
+class ResponseHeaderV2(Struct):
+    # Flexible response / request headers end in field buffer
+    SCHEMA = Schema(
+        ('correlation_id', Int32),
+        ('tags', TaggedFields)
+    )
+
+
 class Request(Struct):
     __metaclass__ = abc.ABCMeta
 
+    FLEXIBLE_VERSION = False
+
     @abc.abstractproperty
     def API_KEY(self):
         """Integer identifier for api request"""
@@ -50,6 +82,16 @@ def expect_response(self):
     def to_object(self):
         return _to_object(self.SCHEMA, self)
 
+    def build_request_header(self, correlation_id, client_id):
+        if self.FLEXIBLE_VERSION:
+            return RequestHeaderV2(self, correlation_id=correlation_id, client_id=client_id)
+        return RequestHeader(self, correlation_id=correlation_id, client_id=client_id)
+
+    def parse_response_header(self, read_buffer):
+        if self.FLEXIBLE_VERSION:
+            return ResponseHeaderV2.decode(read_buffer)
+        return ResponseHeader.decode(read_buffer)
+
 
 class Response(Struct):
     __metaclass__ = abc.ABCMeta

kafka/protocol/parser.py

@@ -4,10 +4,9 @@
 import logging
 
 import kafka.errors as Errors
-from kafka.protocol.api import RequestHeader
 from kafka.protocol.commit import GroupCoordinatorResponse
 from kafka.protocol.frame import KafkaBytes
-from kafka.protocol.types import Int32
+from kafka.protocol.types import Int32, TaggedFields
 from kafka.version import __version__
 
 log = logging.getLogger(__name__)
@@ -59,9 +58,7 @@ def send_request(self, request, correlation_id=None):
         log.debug('Sending request %s', request)
         if correlation_id is None:
             correlation_id = self._next_correlation_id()
-        header = RequestHeader(request,
-                               correlation_id=correlation_id,
-                               client_id=self._client_id)
+        header = request.build_request_header(correlation_id=correlation_id, client_id=self._client_id)
         message = b''.join([header.encode(), request.encode()])
         size = Int32.encode(len(message))
         data = size + message
@@ -135,16 +132,14 @@ def receive_bytes(self, data):
         return responses
 
     def _process_response(self, read_buffer):
-        recv_correlation_id = Int32.decode(read_buffer)
-        log.debug('Received correlation id: %d', recv_correlation_id)
-
         if not self.in_flight_requests:
             raise Errors.CorrelationIdError(
                 'No in-flight-request found for server response'
-                ' with correlation ID %d'
-                % (recv_correlation_id,))
-
+            )
         (correlation_id, request) = self.in_flight_requests.popleft()
+        response_header = request.parse_response_header(read_buffer)
+        recv_correlation_id = response_header.correlation_id
+        log.debug('Received correlation id: %d', recv_correlation_id)
 
         # 0.8.2 quirk
         if (recv_correlation_id == 0 and
@@ -162,6 +157,9 @@ def _process_response(self, read_buffer):
                 'Correlation IDs do not match: sent %d, recv %d'
                 % (correlation_id, recv_correlation_id))
 
+        # Flexible response / request headers end in field buffer
+        if request.FLEXIBLE_VERSION:
+            _ = TaggedFields.decode(read_buffer)
         # decode response
         log.debug('Processing response %s', request.RESPONSE_TYPE.__name__)
         try:
@@ -181,3 +179,4 @@ def _reset_buffer(self):
         self._receiving = False
         self._header.seek(0)
         self._rbuffer = None
+

kafka/protocol/types.py

@@ -196,3 +196,156 @@ def repr(self, list_of_items):
         if list_of_items is None:
             return 'NULL'
         return '[' + ', '.join([self.array_of.repr(item) for item in list_of_items]) + ']'
+
+
+class UnsignedVarInt32(AbstractType):
+    @classmethod
+    def decode(cls, data):
+        value, i = 0, 0
+        while True:
+            b, = struct.unpack('B', data.read(1))
+            if not (b & 0x80):
+                break
+            value |= (b & 0x7f) << i
+            i += 7
+            if i > 28:
+                raise ValueError('Invalid value {}'.format(value))
+        value |= b << i
+        return value
+
+    @classmethod
+    def encode(cls, value):
+        value &= 0xffffffff
+        ret = b''
+        while (value & 0xffffff80) != 0:
+            b = (value & 0x7f) | 0x80
+            ret += struct.pack('B', b)
+            value >>= 7
+        ret += struct.pack('B', value)
+        return ret
+
+
+class VarInt32(AbstractType):
+    @classmethod
+    def decode(cls, data):
+        value = UnsignedVarInt32.decode(data)
+        return (value >> 1) ^ -(value & 1)
+
+    @classmethod
+    def encode(cls, value):
+        # bring it in line with the java binary repr
+        value &= 0xffffffff
+        return UnsignedVarInt32.encode((value << 1) ^ (value >> 31))
+
+
+class VarInt64(AbstractType):
+    @classmethod
+    def decode(cls, data):
+        value, i = 0, 0
+        while True:
+            b = data.read(1)
+            if not (b & 0x80):
+                break
+            value |= (b & 0x7f) << i
+            i += 7
+            if i > 63:
+                raise ValueError('Invalid value {}'.format(value))
+        value |= b << i
+        return (value >> 1) ^ -(value & 1)
+
+    @classmethod
+    def encode(cls, value):
+        # bring it in line with the java binary repr
+        value &= 0xffffffffffffffff
+        v = (value << 1) ^ (value >> 63)
+        ret = b''
+        while (v & 0xffffffffffffff80) != 0:
+            b = (value & 0x7f) | 0x80
+            ret += struct.pack('B', b)
+            v >>= 7
+        ret += struct.pack('B', v)
+        return ret
+
+
+class CompactString(String):
+    def decode(self, data):
+        length = UnsignedVarInt32.decode(data) - 1
+        if length < 0:
+            return None
+        value = data.read(length)
+        if len(value) != length:
+            raise ValueError('Buffer underrun decoding string')
+        return value.decode(self.encoding)
+
+    def encode(self, value):
+        if value is None:
+            return UnsignedVarInt32.encode(0)
+        value = str(value).encode(self.encoding)
+        return UnsignedVarInt32.encode(len(value) + 1) + value
+
+
+class TaggedFields(AbstractType):
+    @classmethod
+    def decode(cls, data):
+        num_fields = UnsignedVarInt32.decode(data)
+        ret = {}
+        if not num_fields:
+            return ret
+        prev_tag = -1
+        for i in range(num_fields):
+            tag = UnsignedVarInt32.decode(data)
+            if tag <= prev_tag:
+                raise ValueError('Invalid or out-of-order tag {}'.format(tag))
+            prev_tag = tag
+            size = UnsignedVarInt32.decode(data)
+            val = data.read(size)
+            ret[tag] = val
+        return ret
+
+    @classmethod
+    def encode(cls, value):
+        ret = UnsignedVarInt32.encode(len(value))
+        for k, v in value.items():
+            # do we allow for other data types ?? It could get complicated really fast
+            assert isinstance(v, bytes), 'Value {} is not a byte array'.format(v)
+            assert isinstance(k, int) and k > 0, 'Key {} is not a positive integer'.format(k)
+            ret += UnsignedVarInt32.encode(k)
+            ret += v
+        return ret
+
+
+class CompactBytes(AbstractType):
+    @classmethod
+    def decode(cls, data):
+        length = UnsignedVarInt32.decode(data) - 1
+        if length < 0:
+            return None
+        value = data.read(length)
+        if len(value) != length:
+            raise ValueError('Buffer underrun decoding Bytes')
+        return value
+
+    @classmethod
+    def encode(cls, value):
+        if value is None:
+            return UnsignedVarInt32.encode(0)
+        else:
+            return UnsignedVarInt32.encode(len(value) + 1) + value
+
+
+class CompactArray(Array):
+
+    def encode(self, items):
+        if items is None:
+            return UnsignedVarInt32.encode(0)
+        return b''.join(
+            [UnsignedVarInt32.encode(len(items) + 1)] +
+            [self.array_of.encode(item) for item in items]
+        )
+
+    def decode(self, data):
+        length = UnsignedVarInt32.decode(data) - 1
+        if length == -1:
+            return None
+        return [self.array_of.decode(data) for _ in range(length)]
+