Azure CI: Cache

Try to use caching for as much as possible on Azure.
This might help to reuse AMReX objects between our weekly updates.
It might also be just way too large and get evicted quickly.

.azure-pipelines.yml

@@ -13,9 +13,10 @@ jobs:
     WARPX_CI_NUM_MAKE_JOBS: 2
     WARPX_CI_CCACHE: 'TRUE'
     WARPX_CI_OPENPMD: 'TRUE'
-    FFTW_HOME: '/usr/'
-    BLASPP_HOME: '/usr/local/'
-    LAPACKPP_HOME: '/usr/local/'
+    WARPX_CI_TMP: '/tmp/ci'
+    FFTW_HOME: '/usr'
+    BLASPP_HOME: '/usr/local'
+    LAPACKPP_HOME: '/usr/local'
     OMP_NUM_THREADS: 1
 
   strategy:
@@ -42,12 +43,39 @@ jobs:
   timeoutInMinutes: 90
 
   steps:
-  - script: |
+  # set up caches:
+  # - once stored under a key, they become immutable (even if cache content changes)
+  # - for a refresh the key has to change, e.g., hash of a tracked file in the key
+  - task: Cache@2
+    inputs:
+      key: 'Ccache | "$(System.JobName)" | cmake/dependencies/AMReX.cmake | run_test.sh'
+      restoreKeys: |
+         Ccache | "$(System.JobName)" | cmake/dependencies/AMReX.cmake | run_test.sh
+         Ccache | "$(System.JobName)" | cmake/dependencies/AMReX.cmake
+         Ccache | "$(System.JobName)"
+         Ccache
+      path: /home/vsts/.ccache
+      cacheHitVar: CCACHE_CACHE_RESTORED
+    displayName: Cache Ccache Objects
+
+  - task: Cache@2
+    inputs:
+      key: 'Python3 | "$(System.JobName)" | run_test.sh'
+      restoreKeys: |
+         Python3 | "$(System.JobName)" | run_test.sh
+         Python3 | "$(System.JobName)"
+         Python3
+      path: /home/vsts/.local/lib/python3.8
+      cacheHitVar: PYTHON38_CACHE_RESTORED
+    displayName: Cache Python Libraries
+
+  - bash: |
       cat /proc/cpuinfo | grep "model name" | sort -u
-      sudo apt update
+      df -h
       sudo apt install -y ccache gcc gfortran g++ openmpi-bin libopenmpi-dev \
         libfftw3-dev libfftw3-mpi-dev libhdf5-openmpi-dev pkg-config make \
         python3 python3-pip python3-venv python3-setuptools libblas-dev liblapack-dev
+      ccache --set-config=max_size=10.0G
       sudo update-alternatives --install /usr/bin/python python /usr/bin/python3 2
       sudo update-alternatives --set python /usr/bin/python3
       python -m pip install --upgrade pip
@@ -58,21 +86,30 @@ jobs:
       export PATH="$HOME/.local/bin:$PATH"
       python -m pip install --upgrade matplotlib mpi4py numpy scipy yt
       export CEI_SUDO="sudo"
+      export CEI_TMP="/tmp/cei"
       sudo curl -L -o /usr/local/bin/cmake-easyinstall https://git.io/JvLxY
       sudo chmod a+x /usr/local/bin/cmake-easyinstall
       if [ "${WARPX_CI_OPENPMD:-FALSE}" == "TRUE" ]; then
         cmake-easyinstall --prefix=/usr/local git+https://github.com/openPMD/[email protected] \
+          -DCMAKE_CXX_COMPILER_LAUNCHER=$(which ccache) \
           -DopenPMD_USE_PYTHON=OFF -DBUILD_TESTING=OFF -DBUILD_EXAMPLES=OFF -DBUILD_CLI_TOOLS=OFF
         python -m pip install --upgrade openpmd-api
       fi
       if [[ "${WARPX_CI_RZ_OR_NOMPI:-FALSE}" == "TRUE" || "${WARPX_CI_PYTHON_MAIN:-FALSE}" == "TRUE" ]]; then
         cmake-easyinstall --prefix=/usr/local git+https://bitbucket.org/icl/blaspp.git \
+          -DCMAKE_CXX_COMPILER_LAUNCHER=$(which ccache) \
           -Duse_openmp=OFF -Dbuild_tests=OFF -DCMAKE_VERBOSE_MAKEFILE=ON
         cmake-easyinstall --prefix=/usr/local git+https://bitbucket.org/icl/lapackpp.git \
+          -DCMAKE_CXX_COMPILER_LAUNCHER=$(which ccache) \
           -Duse_cmake_find_lapack=ON -Dbuild_tests=OFF -DCMAKE_VERBOSE_MAKEFILE=ON
       fi
+      df -h
     displayName: 'Install dependencies'
+#    condition: eq(variables.CCACHE_CACHE_RESTORED, 'false') and ...
 
-  - script: |
+  - bash: |
+      df -h
       ./run_test.sh
+      rm -rf ${WARPX_CI_TMP}
+      df -h
     displayName: 'Build & test'