Use ccache in build-in-docker by default

CONTRIBUTING.md

@@ -49,9 +49,12 @@ so it should be invoked as one would invoke Maven, e.g.: `build/build-in-docker
 ### cudf Submodule and Build
 
 [RAPIDS cuDF](https://github.com/rapidsai/cudf) is being used as a submodule in this project.
-Due to the lengthy build of libcudf, it is **not cleaned** during a normal Maven clean phase.
-Use `-Dlibcudf.clean.skip=true` to clean the libcudf build area in addition to the normal clean
-of `target/` directories.
+Due to the lengthy build of libcudf, it is **not cleaned** during a normal Maven clean phase
+unless built using `build/build-in-docker`. `build/build-in-docker` uses `ccache` by default
+unless CCACHE_DISABLE=1 is set in the environment.
+
+Boolean property `-Dlibcudf.clean.skip=false` can also be set manually to clean libcudf
+build area in addition to the normal clean of `target/` directories.
 
 Currently libcudf is only configured once and the build relies on cmake to re-configure as needed.
 This is because libcudf currently is rebuilding almost entirely when it is configured with the same

build-libcudf.xml

@@ -36,6 +36,7 @@
           executable="cmake"
           if:true="${needConfigure}">
       <arg value="${cudf.path}/cpp"/>
+      <arg line="${cmake.ccache.opts}"/>
       <arg value="-DBUILD_SHARED_LIBS=OFF"/>
       <arg value="-DBUILD_TESTS=OFF"/>
       <arg value="-DCMAKE_CUDA_ARCHITECTURES=${GPU_ARCHS}"/>

build/build-in-docker

@@ -46,21 +46,44 @@ $DOCKER_CMD build -f $REPODIR/thirdparty/cudf/java/ci/Dockerfile.centos7 \
   -t $IMAGE_NAME \
   $REPODIR/thirdparty/cudf/java/ci
 
+CCACHE_OPTS=(
+  "-DCMAKE_C_COMPILER_LAUNCHER=ccache"
+  "-DCMAKE_CXX_COMPILER_LAUNCHER=ccache"
+  "-DCMAKE_CUDA_COMPILER_LAUNCHER=ccache"
+  "-DCMAKE_CXX_LINKER_LAUNCHER=ccache"
+)
+
+_CUDF_CLEAN_SKIP=""
+# if ccache is enabled and libcudf.clean.skip not provided
+# by the user remove the cpp build directory
+#
+if [[ "$CCACHE_DISABLE" != "1" ]]; then
+  if [[ ! "$*" =~ " -Dlibcudf.clean.skip=" ]]; then
+    # Don't skip clean if ccache is enabled
+    # unless the user overrides
+    _CUDF_CLEAN_SKIP="-Dlibcudf.clean.skip=false"
+  fi
+fi
+
 $DOCKER_CMD run -it -u $(id -u):$(id -g) --rm \
   -v "/etc/group:/etc/group:ro" \
   -v "/etc/passwd:/etc/passwd:ro" \
   -v "/etc/shadow:/etc/shadow:ro" \
   -v "/etc/sudoers.d:/etc/sudoers.d:ro" \
   -v "$REPODIR:$WORKSPACE_REPODIR:rw" \
   -v "$LOCAL_MAVEN_REPO:$WORKSPACE_MAVEN_REPODIR:rw" \
+  -v "$HOME/.ccache:$HOME/.ccache:rw" \
   --workdir "$WORKSPACE_REPODIR" \
   -e CMAKE_GENERATOR="$CMAKE_GENERATOR" \
   -e CUDA_VISIBLE_DEVICES \
   -e PARALLEL_LEVEL \
   -e VERBOSE \
+  -e CCACHE_DISABLE \
   $IMAGE_NAME \
   scl enable devtoolset-9 "mvn \
     -Dmaven.repo.local=$WORKSPACE_MAVEN_REPODIR \
     -DPER_THREAD_DEFAULT_STREAM=$PER_THREAD_DEFAULT_STREAM \
     -DUSE_GDS=$USE_GDS \
+    -Dcmake.ccache.opts=\"${CCACHE_OPTS[*]}\" \
+    "$_CUDF_CLEAN_SKIP" \
     $*"

pom.xml

@@ -100,6 +100,7 @@
     <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
     <slf4j.version>1.7.30</slf4j.version>
     <submodule.check.skip>false</submodule.check.skip>
+    <cmake.ccache.opts/>
   </properties>
 
   <dependencies>
@@ -260,6 +261,7 @@
                   <env key="CUDF_CPP_BUILD_DIR" value="${libcudf.build.path}"/>
                   <env key="CUDF_ROOT" value="${cudf.path}"/>
                   <arg value="${cudf.path}/java/src/main/native"/>
+                  <arg line="${cmake.ccache.opts}"/>
                   <arg value="-DBUILD_SHARED_LIBS=OFF"/>
                   <arg value="-DCUDA_STATIC_RUNTIME=ON"/>
                   <arg value="-DCUDF_JNI_LIBCUDF_STATIC=ON"/>