Add debhelper to base images (#17)

Add `debhelper` to Ubuntu `gcc` image, document packaging support for
various images.

Author: Bronek

README.md

@@ -15,6 +15,10 @@ of environments and using different C++ compilers.
 [Debian instructions](docker/debian/README.md)
 [RHEL instructions](docker/rhel/README.md)
 
+### Packaging
+
+Only some of the container images provided support packaging.
+
 ## Tools images
 
 Aside from build images, XRPLF projects also use container images with specialized tools, e.g.

docker/debian/Dockerfile

@@ -167,11 +167,19 @@ apt-get update
 apt-get install -t llvm-toolchain-${DEBIAN_VERSION}-${CLANG_VERSION} -y --no-install-recommends clang-${CLANG_VERSION} llvm-${CLANG_VERSION}
 apt-get clean
 rm -rf /var/lib/apt/lists/*
+update-alternatives --install /usr/bin/cc cc /usr/bin/clang-${CLANG_VERSION} 999
+update-alternatives --install \
+    /usr/bin/clang clang /usr/bin/clang-${CLANG_VERSION} 100 \
+    --slave /usr/bin/clang++ clang++ /usr/bin/clang++-${CLANG_VERSION}
+update-alternatives --install \
+    /usr/bin/llvm-cov llvm-cov /usr/bin/llvm-cov-${CLANG_VERSION} 100
+update-alternatives --auto cc
+update-alternatives --auto clang
+update-alternatives --auto llvm-cov
 EOF
+
 ENV CC=/usr/bin/clang-${CLANG_VERSION}
 ENV CXX=/usr/bin/clang++-${CLANG_VERSION}
-# This is required by some build dependencies
-RUN update-alternatives --install /usr/bin/cc cc $CC 999
 
 # Check that the installed Clang version matches the expected version.
 RUN <<EOF

docker/debian/README.md

@@ -29,9 +29,15 @@ versions by specifying the `DEBIAN_VERSION` build argument. There are additional
 arguments to specify as well, namely `GCC_VERSION` for the GCC flavor and
 `CLANG_VERSION` for the Clang flavor.
 
-Run the commands below from the root directory of the repository.
+None of the build images support packaging, since (in order to be access the most
+recent official releases) the compilers are installed from external sources:
 
-#### Building the Docker image for GCC.
+* [gcc Docker Official Image](https://hub.docker.com/_/gcc)
+* [LLVM Debian/Ubuntu nightly packages](https://apt.llvm.org/)
+
+In order to build an image, run the commands below from the root directory of the repository.
+
+#### Building the Docker image for GCC
 
 Ensure you've run the login command above to authenticate with the Docker
 registry.
@@ -55,7 +61,7 @@ docker buildx build . \
   --tag ${CONTAINER_REGISTRY}/${CONTAINER_IMAGE}
 ```
 
-#### Building the Docker image for Clang.
+#### Building the Docker image for Clang
 
 Ensure you've run the login command above to authenticate with the Docker
 registry.

docker/rhel/Dockerfile

@@ -54,12 +54,14 @@ dnf clean -y all
 rm -rf /var/cache/dnf/*
 update-alternatives --install /usr/bin/cc cc /opt/rh/gcc-toolset-${GCC_VERSION}/root/usr/bin/gcc 999
 update-alternatives \
-    --install /usr/bin/gcc gcc /opt/rh/gcc-toolset-${GCC_VERSION}/root/usr/bin/gcc ${GCC_VERSION} \
+    --install /usr/bin/gcc gcc /opt/rh/gcc-toolset-${GCC_VERSION}/root/usr/bin/gcc 100 \
     --slave /usr/bin/g++ g++ /opt/rh/gcc-toolset-${GCC_VERSION}/root/usr/bin/g++ \
     --slave /usr/bin/cpp cpp /opt/rh/gcc-toolset-${GCC_VERSION}/root/usr/bin/cpp \
     --slave /usr/bin/gcov gcov /opt/rh/gcc-toolset-${GCC_VERSION}/root/usr/bin/gcov \
     --slave /usr/bin/gcov-dump gcov-dump /opt/rh/gcc-toolset-${GCC_VERSION}/root/usr/bin/gcov-dump-${GCC_VERSION} \
     --slave /usr/bin/gcov-tool gcov-tool /opt/rh/gcc-toolset-${GCC_VERSION}/root/usr/bin/gcov-tool-${GCC_VERSION}
+update-alternatives --auto cc
+update-alternatives --auto gcc
 EOF
 ENV CC=/usr/bin/gcc
 ENV CXX=/usr/bin/g++
@@ -139,11 +141,12 @@ RUN <<EOF
 dnf install -y --setopt=tsflags=nodocs clang llvm
 dnf clean -y all
 rm -rf /var/cache/dnf/*
+update-alternatives --install /usr/bin/cc cc /usr/bin/clang 999
+update-alternatives --auto cc
 EOF
+
 ENV CC=/usr/bin/clang
 ENV CXX=/usr/bin/clang++
-# This is required by some build dependencies
-RUN update-alternatives --install /usr/bin/cc cc $CC 999
 
 # Check that the installed Clang version is not older than the minimum required.
 ARG MINIMUM_CLANG_VERSION=16

docker/rhel/README.md

@@ -48,9 +48,11 @@ versions by specifying the `RHEL_VERSION` build argument. There are additional
 arguments to specify as well, namely `GCC_VERSION` for the GCC flavor and
 `CLANG_VERSION` for the Clang flavor.
 
-Run the commands below from the root directory of the repository.
+Both build images for `gcc` and `clang` support packaging.
 
-#### Building the Docker image for GCC.
+In order to build an image, run the commands below from the root directory of the repository.
+
+#### Building the Docker image for GCC
 
 Ensure you've run the login command above to authenticate with the Docker
 registry.
@@ -74,7 +76,7 @@ docker buildx build . \
   --tag ${CONTAINER_REGISTRY}/${CONTAINER_IMAGE}
 ```
 
-#### Building the Docker image for Clang.
+#### Building the Docker image for Clang
 
 Ensure you've run the login command above to authenticate with the Docker
 registry.

docker/ubuntu/Dockerfile

@@ -60,23 +60,26 @@ FROM base AS gcc
 # This is not inherited from base image, ensure no manual interaction needed.
 ARG DEBIAN_FRONTEND=noninteractive
 
-# Install GCC and create the necessary symlinks.
+# Install GCC and create the necessary symlinks. We only support packaging with
+# gcc because of the hard package dependencies from libtool to gcc
 ARG GCC_VERSION
 RUN <<EOF
 apt-get update
 apt-get install -y --no-install-recommends \
     gcc-${GCC_VERSION} \
-    g++-${GCC_VERSION}
+    g++-${GCC_VERSION} \
+    debhelper
 apt-get clean
 rm -rf /var/lib/apt/lists/*
 update-alternatives --install /usr/bin/cc cc /usr/bin/gcc-${GCC_VERSION} 999
 update-alternatives \
-    --install /usr/bin/gcc gcc /usr/bin/gcc-${GCC_VERSION} ${GCC_VERSION} \
+    --install /usr/bin/gcc gcc /usr/bin/gcc-${GCC_VERSION} 100 \
     --slave /usr/bin/g++ g++ /usr/bin/g++-${GCC_VERSION} \
-    --slave /usr/bin/cpp cpp /usr/bin/cpp-${GCC_VERSION} \
     --slave /usr/bin/gcov gcov /usr/bin/gcov-${GCC_VERSION} \
     --slave /usr/bin/gcov-dump gcov-dump /usr/bin/gcov-dump-${GCC_VERSION} \
     --slave /usr/bin/gcov-tool gcov-tool /usr/bin/gcov-tool-${GCC_VERSION}
+update-alternatives --auto cc
+update-alternatives --auto gcc
 EOF
 ENV CC=/usr/bin/gcc
 ENV CXX=/usr/bin/g++
@@ -161,11 +164,19 @@ apt-get install -y --no-install-recommends \
     llvm-${CLANG_VERSION}
 apt-get clean
 rm -rf /var/lib/apt/lists/*
+update-alternatives --install /usr/bin/cc cc /usr/bin/clang-${CLANG_VERSION} 999
+update-alternatives --install \
+    /usr/bin/clang clang /usr/bin/clang-${CLANG_VERSION} 100 \
+    --slave /usr/bin/clang++ clang++ /usr/bin/clang++-${CLANG_VERSION}
+update-alternatives --install \
+    /usr/bin/llvm-cov llvm-cov /usr/bin/llvm-cov-${CLANG_VERSION} 100
+update-alternatives --auto cc
+update-alternatives --auto clang
+update-alternatives --auto llvm-cov
 EOF
+
 ENV CC=/usr/bin/clang-${CLANG_VERSION}
 ENV CXX=/usr/bin/clang++-${CLANG_VERSION}
-# This is required by some build dependencies
-RUN update-alternatives --install /usr/bin/cc cc $CC 999
 
 # Check that the installed Clang version matches the expected version.
 RUN <<EOF

docker/ubuntu/README.md

@@ -29,9 +29,11 @@ future versions by specifying the `UBUNTU_VERSION` build argument. There are
 additional arguments to specify as well, namely `GCC_VERSION` for the GCC flavor
 and `CLANG_VERSION` for the Clang flavor.
 
-Run the commands below from the root directory of the repository.
+Build image for `gcc` supports packaging.
 
-#### Building the Docker image for GCC.
+In order to build an image, run the commands below from the root directory of the repository.
+
+#### Building the Docker image for GCC
 
 Ensure you've run the login command above to authenticate with the Docker
 registry.
@@ -55,7 +57,7 @@ docker buildx build . \
   --tag ${CONTAINER_REGISTRY}/${CONTAINER_IMAGE}
 ```
 
-#### Building the Docker image for Clang.
+#### Building the Docker image for Clang
 
 Ensure you've run the login command above to authenticate with the Docker
 registry.