Pyrobuf Library

Introduction

Pyrobuf is an alternative to Google's Python Protobuf library. Pyrobuf generates lightning-fast Cython code that's 2-4x faster than Google's Python Protobuf library using their C++ backend and 20-40x faster than Google's pure-python implementation. What's more, Pyrobuf is self-contained and easy to install.

Requirements

Pyrobuf requires Cython (sudo pip install cython), setuptools (sudo pip install setuptools), and Jinja2 (sudo pip install Jinja2). Pyrobuf does not require protoc. Pyrobuf has been tested with Python 2.7 and Python 3.4.

Installation

To generate usable Python modules from .proto files, simply copy the .proto templates into the folder messages and run build.sh. Pyrobuf will parse the .proto files, generate corresponding Cython code, and then compile and install the resulting Cython libraries.

Use

Suppose you have installed test_message.proto which contains a spec for the message Test. In Python, you can import your new message class by running:

from test_message_proto import Test

With the message class imported, we can create a new message:

test = Test()

Now that we have instantiated a message test, we can fill individual fields:

>>> test.field = 5
>>> test.req_field = 2
>>> test.string_field = "hello!"
>>> test.list_fieldx.append(12)
>>> test.test_ref.field2 = 3.14

And access those same fields:

>>> test.string_field
'hello!'

Once we have at least filled out any "required" fields, we can serialize to a byte array:

>>> test.SerializeToString()
bytearray(b'\x10\x05\x1a\x06hello! \x0c2\t\x19\x1f\x85\xebQ\xb8\x1e\t@P\x02')

We can also deserialize a protobuf message to our message instance:

>>> test.ParseFromString('\x10\x05\x1a\x06hello! \x0c2\t\x19\x1f\x85\xebQ\xb8\x1e\t@P\x02')
25

Note that the ParseFromString method returns the number of bytes consumed.

In addition to serializing and deserializing to and from protobuf messages, Pyrobuf also allows us to serialize and deserialize to and from JSON and native Python dictionaries:

>>> test.SerializeToJson()
'{"field": 5, "req_field": 2, "list_fieldx": [12], "string_field": "hello!", "test_ref": {"field2": 3.14}}'

>>> test.ParseFromJson('{"field": 5, "req_field": 2, "list_fieldx": [12], "string_field": "hello!", "test_ref": {"field2": 3.14}}')

>>> test.SerializeToDict()
{'field': 5,
 'list_fieldx': [12],
 'req_field': 2,
 'string_field': 'hello!',
 'test_ref': {'field2': 3.14}}

>>> test.ParseFromDict({'field': 5, 'list_fieldx': [12], 'req_field': 2, 'string_field': 'hello!', 'test_ref': {'field2': 3.14}})

Performance

On my development machine (Ubuntu 14.04), Pyrobuf is roughly 2.0x as fast as Google's library for message serialization and 2.3x as fast for message deserialization when using the C++ backend for Google's library:

> python tests/perf_test.py
Google took 1.649168 seconds to serialize
Pyrobuf took 0.825525 seconds to serialize
Google took 1.113041 seconds to deserialize
Pyrobuf took 0.466113 seconds to deserialize

When not using the C++ backend, Pyrobuf is roughly 25x as fast for serialization and 55x as fast for deserialization:

Google took 20.215662 seconds to serialize
Pyrobuf took 0.819555 seconds to serialize
Google took 24.990137 seconds to deserialize
Pyrobuf took 0.455732 seconds to deserialize

Differences from the Google library

For the most part, Pyrobuf should be a drag-and-drop replacement for the Google protobuf library. There are a few differences, though. First, Pyrobuf does not currently implement the MergeFrom and MergeFromString methods that allow you to populate a message class from multiple protobuf messages. We may add these methods later.

Second, Pyrobuf simply assumes that the schema being used for a given message is the same on the send and receive ends, so changing the type of a field on one end without changing it on the other may cause bugs; adding or removing fields will not break anything.