1 Protocol Buffers - Google's data interchange format 2 Copyright 2008 Google Inc. 3 4 This directory contains the Python Protocol Buffers runtime library. 5 6 Normally, this directory comes as part of the protobuf package, available 7 from: 8 9 https://developers.google.com/protocol-buffers/ 10 11 The complete package includes the C++ source code, which includes the 12 Protocol Compiler (protoc). If you downloaded this package from PyPI 13 or some other Python-specific source, you may have received only the 14 Python part of the code. In this case, you will need to obtain the 15 Protocol Compiler from some other source before you can use this 16 package. 17 18 Development Warning 19 =================== 20 21 The Python implementation of Protocol Buffers is not as mature as the C++ 22 and Java implementations. It may be more buggy, and it is known to be 23 pretty slow at this time. If you would like to help fix these issues, 24 join the Protocol Buffers discussion list and let us know! 25 26 Installation 27 ============ 28 29 1) Make sure you have Python 2.4 or newer. If in doubt, run: 30 31 $ python -V 32 33 2) 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 40 3) 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 46 4) 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 65 5) 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 76 Usage 77 ===== 78 79 The complete documentation for Protocol Buffers is available via the 80 web at: 81 82 https://developers.google.com/protocol-buffers/ 83 84 C++ Implementation 85 ================== 86 87 The C++ implementation for Python messages is built as a Python extension to 88 improve the overall protobuf Python performance. 89 90 To use the C++ implementation, you need to: 91 1) Install the C++ protobuf runtime library, please see instructions in the 92 parent directory. 93 2) Export an environment variable: 94 95 $ export PROTOCOL_BUFFERS_PYTHON_IMPLEMENTATION=cpp 96 $ export PROTOCOL_BUFFERS_PYTHON_IMPLEMENTATION_VERSION=2 97 98 You need to export this variable before running setup.py script to build and 99 install the extension. You must also set the variable at runtime, otherwise 100 the pure-Python implementation will be used. In a future release, we will 101 change the default so that C++ implementation is used whenever it is available. 102 It is strongly recommended to run `python setup.py test` after setting the 103 variable to "cpp", so the tests will be against C++ implemented Python 104 messages. 105 106