README.md
1Protocol Buffers - Google's data interchange format
2===================================================
3
4[](https://fusion.corp.google.com/projectanalysis/current/KOKORO/prod:protobuf%2Fgithub%2Fmaster%2Fubuntu%2Fpython%2Fcontinuous) [](https://fusion.corp.google.com/projectanalysis/current/KOKORO/prod:protobuf%2Fgithub%2Fmaster%2Fubuntu%2Fpython_compatibility%2Fcontinuous) [](https://fusion.corp.google.com/projectanalysis/current/KOKORO/prod:protobuf%2Fgithub%2Fmaster%2Fubuntu%2Fpython_cpp%2Fcontinuous) [](https://fusion.corp.google.com/projectanalysis/current/KOKORO/prod:protobuf%2Fgithub%2Fmaster%2Fmacos%2Fpython%2Fcontinuous) [](https://fusion.corp.google.com/projectanalysis/current/KOKORO/prod:protobuf%2Fgithub%2Fmaster%2Fmacos%2Fpython_cpp%2Fcontinuous) [](https://python-compatibility-tools.appspot.com/one_badge_target?package=protobuf)
5
6Copyright 2008 Google Inc.
7
8This directory contains the Python Protocol Buffers runtime library.
9
10Normally, this directory comes as part of the protobuf package, available
11from:
12
13 https://developers.google.com/protocol-buffers/
14
15The complete package includes the C++ source code, which includes the
16Protocol Compiler (protoc). If you downloaded this package from PyPI
17or some other Python-specific source, you may have received only the
18Python part of the code. In this case, you will need to obtain the
19Protocol Compiler from some other source before you can use this
20package.
21
22Development Warning
23===================
24
25The Python implementation of Protocol Buffers is not as mature as the C++
26and Java implementations. It may be more buggy, and it is known to be
27pretty slow at this time. If you would like to help fix these issues,
28join the Protocol Buffers discussion list and let us know!
29
30Installation
31============
32
331) Make sure you have Python 2.7 or newer. If in doubt, run:
34
35 $ python -V
36
372) If you do not have setuptools installed, note that it will be
38 downloaded and installed automatically as soon as you run `setup.py`.
39 If you would rather install it manually, you may do so by following
40 the instructions on [this page](https://packaging.python.org/en/latest/installing.html#setup-for-installing-packages).
41
423) Build the C++ code, or install a binary distribution of `protoc`. If
43 you install a binary distribution, make sure that it is the same
44 version as this package. If in doubt, run:
45
46 $ protoc --version
47
484) Build and run the tests:
49
50 $ python setup.py build
51 $ python setup.py test
52
53 To build, test, and use the C++ implementation, you must first compile
54 `libprotobuf.so`:
55
56 $ (cd .. && make)
57
58 On OS X:
59
60 If you are running a Homebrew-provided Python, you must make sure another
61 version of protobuf is not already installed, as Homebrew's Python will
62 search `/usr/local/lib` for `libprotobuf.so` before it searches
63 `../src/.libs`.
64
65 You can either unlink Homebrew's protobuf or install the `libprotobuf` you
66 built earlier:
67
68 $ brew unlink protobuf
69
70 or
71
72 $ (cd .. && make install)
73
74 On other *nix:
75
76 You must make `libprotobuf.so` dynamically available. You can either
77 install libprotobuf you built earlier, or set `LD_LIBRARY_PATH`:
78
79 $ export LD_LIBRARY_PATH=../src/.libs
80
81 or
82
83 $ (cd .. && make install)
84
85 To build the C++ implementation run:
86
87 $ python setup.py build --cpp_implementation
88
89 Then run the tests like so:
90
91 $ python setup.py test --cpp_implementation
92
93 If some tests fail, this library may not work correctly on your
94 system. Continue at your own risk.
95
96 Please note that there is a known problem with some versions of
97 Python on Cygwin which causes the tests to fail after printing the
98 error: `sem_init: Resource temporarily unavailable`. This appears
99 to be a [bug either in Cygwin or in
100 Python](http://www.cygwin.com/ml/cygwin/2005-07/msg01378.html).
101
102 We do not know if or when it might be fixed. We also do not know
103 how likely it is that this bug will affect users in practice.
104
1055) Install:
106
107 $ python setup.py install
108
109 or:
110
111 $ (cd .. && make install)
112 $ python setup.py install --cpp_implementation
113
114 This step may require superuser privileges.
115 NOTE: To use C++ implementation, you need to export an environment
116 variable before running your program. See the "C++ Implementation"
117 section below for more details.
118
119Usage
120=====
121
122The complete documentation for Protocol Buffers is available via the
123web at:
124
125 https://developers.google.com/protocol-buffers/
126
127C++ Implementation
128==================
129
130The C++ implementation for Python messages is built as a Python extension to
131improve the overall protobuf Python performance.
132
133To use the C++ implementation, you need to install the C++ protobuf runtime
134library, please see instructions in the parent directory.
135
){kind=link}
){kind=link}
){kind=link}
){kind=link}
){kind=link}