Configurable CC/CXX compiler toolchain in Dockerfiles. (#1402)

Allows to build Docker images with Clang.

.travis.yml

@@ -22,14 +22,15 @@ cache:
     - /home/travis/docker/
 
 env:
-  - LSB_RELEASE=trusty DOCKER_CACHE_FILE=/home/travis/docker/trusty-cache.tar.gz
-  - LSB_RELEASE=xenial DOCKER_CACHE_FILE=/home/travis/docker/xenial-cache.tar.gz
-  - LSB_RELEASE=jessie DOCKER_CACHE_FILE=/home/travis/docker/jessie-cache.tar.gz
-  - LSB_RELEASE=stretch DOCKER_CACHE_FILE=/home/travis/docker/stretch-cache.tar.gz
+  - LSB_RELEASE=trusty DOCKER_CACHE_FILE=/home/travis/docker/trusty-cache.tar.gz CC=gcc CXX=g++
+  - LSB_RELEASE=xenial DOCKER_CACHE_FILE=/home/travis/docker/xenial-cache.tar.gz CC=gcc CXX=g++
+  - LSB_RELEASE=jessie DOCKER_CACHE_FILE=/home/travis/docker/jessie-cache.tar.gz CC=gcc CXX=g++
+  - LSB_RELEASE=stretch DOCKER_CACHE_FILE=/home/travis/docker/stretch-cache.tar.gz CC=gcc CXX=g++
 
 before_install: scripts/load_docker_cache.sh
 
 install: true
 script:
   - docker build ${TRAVIS_BUILD_DIR} -t cartographer:${LSB_RELEASE} -f Dockerfile.${LSB_RELEASE}
+      --build-arg cc=$CC --build-arg cxx=$CXX
   - scripts/save_docker_cache.sh

Dockerfile.jessie

@@ -14,6 +14,13 @@
 
 FROM debian:jessie
 
+ARG cc
+ARG cxx
+
+# Set the preferred C/C++ compiler toolchain, if given (otherwise default).
+ENV CC=$cc
+ENV CXX=$cxx
+
 # This base image doesn't ship with sudo.
 RUN apt-get update && apt-get install -y sudo && rm -rf /var/lib/apt/lists/*
 

Dockerfile.stretch

@@ -14,6 +14,13 @@
 
 FROM debian:stretch
 
+ARG cc
+ARG cxx
+
+# Set the preferred C/C++ compiler toolchain, if given (otherwise default).
+ENV CC=$cc
+ENV CXX=$cxx
+
 # This base image doesn't ship with sudo.
 RUN apt-get update && apt-get install -y sudo && rm -rf /var/lib/apt/lists/*
 

Dockerfile.trusty

@@ -13,6 +13,14 @@
 # limitations under the License.
 
 FROM ubuntu:trusty
+
+ARG cc
+ARG cxx
+
+# Set the preferred C/C++ compiler toolchain, if given (otherwise default).
+ENV CC=$cc
+ENV CXX=$cxx
+
 COPY scripts/install_debs_cmake.sh cartographer/scripts/
 RUN cartographer/scripts/install_debs_cmake.sh && rm -rf /var/lib/apt/lists/*
 COPY scripts/install_ceres.sh cartographer/scripts/

Dockerfile.trusty.bazel

@@ -13,6 +13,14 @@
 # limitations under the License.
 
 FROM ubuntu:trusty
+
+ARG cc
+ARG cxx
+
+# Set the preferred C/C++ compiler toolchain, if given (otherwise default).
+ENV CC=$cc
+ENV CXX=$cxx
+
 COPY scripts/install_debs_bazel.sh cartographer/scripts/
 RUN cartographer/scripts/install_debs_bazel.sh && rm -rf /var/lib/apt/lists/*
 COPY . cartographer

Dockerfile.xenial

@@ -12,8 +12,16 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
+
 FROM ubuntu:xenial
 
+ARG cc
+ARG cxx
+
+# Set the preferred C/C++ compiler toolchain, if given (otherwise default).
+ENV CC=$cc
+ENV CXX=$cxx
+
 # This base image doesn't ship with sudo.
 RUN apt-get update && apt-get install -y sudo && rm -rf /var/lib/apt/lists/*
 

scripts/install_debs_cmake.sh

@@ -35,6 +35,7 @@ else
 fi
 
 sudo apt-get install -y \
+    clang \
     g++ \
     git \
     google-mock \