README.txt
1Protocol Buffers - Google's data interchange format
2Copyright 2008 Google Inc.
3
4This directory contains the Python Protocol Buffers runtime library.
5
6Normally, this directory comes as part of the protobuf package, available
7from:
8
9 https://developers.google.com/protocol-buffers/
10
11The complete package includes the C++ source code, which includes the
12Protocol Compiler (protoc). If you downloaded this package from PyPI
13or some other Python-specific source, you may have received only the
14Python part of the code. In this case, you will need to obtain the
15Protocol Compiler from some other source before you can use this
16package.
17
18Development Warning
19===================
20
21The Python implementation of Protocol Buffers is not as mature as the C++
22and Java implementations. It may be more buggy, and it is known to be
23pretty slow at this time. If you would like to help fix these issues,
24join the Protocol Buffers discussion list and let us know!
25
26Installation
27============
28
291) Make sure you have Python 2.4 or newer. If in doubt, run:
30
31 $ python -V
32
332) If you do not have setuptools installed, note that it will be
34 downloaded and installed automatically as soon as you run setup.py.
35 If you would rather install it manually, you may do so by following
36 the instructions on this page:
37
38 http://peak.telecommunity.com/DevCenter/EasyInstall#installation-instructions
39
403) Build the C++ code, or install a binary distribution of protoc. If
41 you install a binary distribution, make sure that it is the same
42 version as this package. If in doubt, run:
43
44 $ protoc --version
45
464) Build and run the tests:
47
48 $ python setup.py build
49 $ python setup.py google_test
50
51 If you want to test c++ implementation, run:
52 $ python setup.py test --cpp_implementation
53
54 If some tests fail, this library may not work correctly on your
55 system. Continue at your own risk.
56
57 Please note that there is a known problem with some versions of
58 Python on Cygwin which causes the tests to fail after printing the
59 error: "sem_init: Resource temporarily unavailable". This appears
60 to be a bug either in Cygwin or in Python:
61 http://www.cygwin.com/ml/cygwin/2005-07/msg01378.html
62 We do not know if or when it might me fixed. We also do not know
63 how likely it is that this bug will affect users in practice.
64
655) Install:
66
67 $ python setup.py install
68 or:
69 $ python setup.py install --cpp_implementation
70
71 This step may require superuser privileges.
72 NOTE: To use C++ implementation, you need to install C++ protobuf runtime
73 library of the same version and export the environment variable before this
74 step. See the "C++ Implementation" section below for more details.
75
76Usage
77=====
78
79The complete documentation for Protocol Buffers is available via the
80web at:
81
82 https://developers.google.com/protocol-buffers/
83
84C++ Implementation
85==================
86
87The C++ implementation for Python messages is built as a Python extension to
88improve the overall protobuf Python performance.
89
90To use the C++ implementation, you need to:
911) Install the C++ protobuf runtime library, please see instructions in the
92 parent directory.
932) Export an environment variable:
94
95 $ export PROTOCOL_BUFFERS_PYTHON_IMPLEMENTATION=cpp
96 $ export PROTOCOL_BUFFERS_PYTHON_IMPLEMENTATION_VERSION=2
97
98You need to export this variable before running setup.py script to build and
99install the extension. You must also set the variable at runtime, otherwise
100the pure-Python implementation will be used. In a future release, we will
101change the default so that C++ implementation is used whenever it is available.
102It is strongly recommended to run `python setup.py test` after setting the
103variable to "cpp", so the tests will be against C++ implemented Python
104messages.
105
106