Caching with CPM.cmake and ccache on GitHub Actions (original) (raw)

Caching with GitHub Actions

You can use CPM_SOURCE_CACHE on GitHub Actions workflows cache and combine it with ccache, to make your CI faster.

CPM.cmake

You need to set a path on actions/cache to CPM and use the same path on CPM_SOURCE_CACHE. Here we are using ~/cpm-cache:

• name: Set up cache id: cache-cpm uses: actions/cache@v2 with: path: ~/cpm-cache key: runner.os−cpm−{{ runner.os }}-cpm-runner.os−cpm−{{ hashFiles('**/') }} restore-keys: | ${{ runner.os }}-cpm-

• name: Build CMake run: | mkdir build && cd build cmake -DCPM_SOURCE_CACHE=~/cpm-cache .. make -j2

ccache

To implement ccache to your workflow:

You need to define some environment variable to tell where ccache will put .ccache and additional informations:

env: CCACHE_VERSION: 4.6 CCACHE_BASEDIR: ${GITHUB_WORKSPACE} CCACHE_DIR: ${GITHUB_WORKSPACE}/.ccache CCACHE_COMPRESS: true CCACHE_COMPRESSLEVEL: 6 CCACHE_MAXSIZE: 400M

• CCACHE_VERSION is used later in this tutorial in ccache step. To find possible version checkout ccache fork that cristianadam maintain to have easy to download release assets.
• CCACHE_DIR will be cache in the ccache_cache step. Check ccache documentation for the other environment variable.

You need to install it:

• name: Download ccache id: ccache shell: cmake -P {0} run: | set(ccache_url "https://github.com/cristianadam/ccache/releases/download/v$ENV{CCACHE_VERSION}/${ { runner.os } }.tar.xz") file(DOWNLOAD "${ccache_url}" ./ccache.tar.xz SHOW_PROGRESS) execute_process(COMMAND ${CMAKE_COMMAND} -E tar xvf ./ccache.tar.xz)
• name: Add ccache to PATH run: echo "$(pwd)" >> $GITHUB_PATH

Enable ccache support:

• name: Prepare ccache timestamp id: ccache_cache_timestamp shell: cmake -P {0} run: | string(TIMESTAMP current_date "%Y-%m-%d-%H;%M;%S" UTC) message("::set-output name=timestamp::${current_date}")

• name: ccache cache files id: ccache_cache uses: actions/cache@v2 with: path: .ccache key:  matrix.config.name −ccache−{ { matrix.config.name } }-ccache- matrix.config.name −ccache−{ { steps.ccache_cache_timestamp.outputs.timestamp } } restore-keys: | ${ { matrix.config.name } }-ccache-

Finally when running your CMake your either need to add:

-D CMAKE_C_COMPILER_LAUNCHER=ccache
-D CMAKE_CXX_COMPILER_LAUNCHER=ccache

or you can have a look at CCache.cmake.

More information on how to set up your CMake to use ccache here. The author also created a complete example : cristianadam/HelloWorld

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