How to use and develop libcaosdb

Dependencies

  • See the dependencies file, install with pip install -r requiremens.txt.

Build

Building with make

Make sure that the dependencies (see above) are fulfilled. On systems which have make installed, type this in your command line terminal:

make conan

Manual build

We use cmake as build tool, with Conan as package manager. The compiler must support the C++17 standard.

  1. clone/update the subrepo git submodule update --init proto

  2. mkdir build && cd build

  3. conan install .. -s "compiler.libcxx=libstdc++11"

  4. cmake -B . ..

  5. cmake --build .

You may also want to install libcaosdb system-wide to CMAKE_INSTALL_PREFIX/lib by

  1. cmake --install .

The default install prefix is ~/.local. It can be set by adding -DCMAKE_INSTALL_PREFIX=/path/to/install/prefix to the first cmake command (3.).

Note

The C++ CaosDB library links against other libraries which are installed by Conan. So if you want to switch to newer versions of those libraries (possible reasons may be security releases or bug fixes), it is not sufficient to update your system libraries, but you have to update your Conan content and then rebuild libcaosdb.

If you want to build or install libcaosdb without the use of Conan, feel free to rewrite the CMakeLists.txt as needed. The CaosDB project is open to merge requests which support multiple ways of installation.

How to build on MacOS

If you use apple-clang as the compiler: Instead of the above conan command (2.) use

  1. conan install .. -s "compiler.cppstd=17"

and continue as you would when building on a Linux system. You may have to add build/lib/ (or, alternatively after installation, CMAKE_INSTALL_PREFIX/lib) to your DYLD_LIBRARY_PATH environmental variable.

Problems and solutions

  • Make sure that your Conan version supports your XCode version. A typical symptom of version mismatch is for example conan complaining about incompatible compiler.version settings. You may need to rerun any conan and cmake commands (and delete cache files first) after compiler updates.

How to build on Windows

We use Visual Studio 2019 as compiler. We use cmake as build tool.

  1. clone/update the subrepo git submodule update --init proto

  2. mkdir build

  3. cd build

  4. conan install .. -g visual_studio -s arch=x86_64 -s build_type=Release -s compiler.toolset=v142 -s compiler.version=16 -s compiler.runtime=MD --build=missing --update

  5. cmake -B . ..

  6. open libcaosdb.sln with Visual Studio, change the buildtype to Release and build the project. (You can open Tools/Command Line/Developer Command Prompt and execute msbuild libcaosdb.sln /property:Configuration=Release)

Known problems

  • Linking dynamic libraries currently fails on Windows. So probably other CaosDB libraries which make use of libcaosdb also will not build. This is a known bug and we hope to fix this in the next release. See #34

Troubleshooting

Warning: WARNING: GCC OLD ABI COMPATIBILITY

Just do what it says. Either run

conan profile update settings.compiler.libcxx=libstdc++11 default

or change ~/.conan/profiles/default or use another conan profile.

/bin/sh: line 1: cmake: command not found

Install cmake.

conan install fails due to missing prebuilts

When conan install fails during the installation of the dependencies because a precompiled package is not available for your specific settings, try adding the --build=missing option: conan install .. [ other options ] --build=missing. This should download and compile the sources of the dependencies.

cmake fails when using the debug flag

Depending on the clang version it might be necessary to additionally use the following flag: -DCMAKE_CXX_FLAGS="-Wno-unused-parameter"

conan uses outdated cppstd during install

If you experience compiler errors during a conan install process due to, e.g., std::string_view being unavailable, try specifying the cpp standard manually by conan install .. [other options] -s "compiler.cppstd=17".

Client Configuration

You can use a json file for the configuration of the client. See test/test_data/test_caosdb_client.json for an example. You may use caosdb-client-configuration-schema.json to validate your schema. Typically, you will need to provide the path to your SSL certificate.

The client will load the configuration file from the first existing file in the following locations (precedence from highest to lowest):

  1. A file specified by the environment variable $CAOSDB_CLIENT_CONFIGURATION.

  2. $PWD/caosdb_client.json

  3. $PWD/caosdb-client.json

  4. $PWD/.caosdb_client.json

  5. $PWD/.caosdb-client.json

  6. $HOME/caosdb_client.json

  7. $HOME/caosdb-client.json

  8. $HOME/.caosdb_client.json

  9. $HOME/.caosdb-client.json

Develop

Unit tests

Build

For the tests there is a slightly different setup required (with option -D CMAKE_BUILD_TYPE=Debug)

  1. mkdir build && cd build/

  2. conan install .. (with gcc, append -s "compiler.libcxx=libstdc++11", with apple-clang, append -s compiler.cppstd=17)

  3. cmake -B . -D CMAKE_BUILD_TYPE=Debug ..

    • If your clang-format version is too old, formatting, linting etc. can be skipped: cmake -B . -D CMAKE_BUILD_TYPE=Debug -D SKIP_LINTING=ON ..

    • Depending on the clang version it may be necessary to also add -DCMAKE_CXX_FLAGS="-Wno-unused-parameter"

  4. cmake --build .

Run

In the build directory, run ctest

Framework

We use GoogleTest for unit testing.

Test coverage

We use gcov and lcov for generating test coverage reports.

In the build directory, generate the coverage report by running cmake --build . --target unit_test_coverage.

Note that this special target will run the tests again. Thus it is not necessary to run ctest prior to this target.

The coverage report can be viewed in a browser by opening <build_directory>/unit_test_coverage/index.html.

Code formatting

  • install clang-format on your system.

  • clang-format -i --verbose $(find test/ src/ include/ -type f -iname "*.cpp" -o -iname "*.h" -o -iname "*.h.in")

Naming conventions

Please adhere to Google’s C++ naming conventions.

Documentation

To build the documentation, run in the build directory

  • cmake --build . --target doc-doxygen (generate Doxygen)

  • cmake --build . --target doc-sphinx (generate Sphinx)