Add rosidl_rust to a sourced overlay in the docker image

Dockerfile

@@ -15,10 +15,15 @@ RUN apt-get update && apt-get install -y \
 RUN curl --proto '=https' --tlsv1.2 -sSf https://sh.rustup.rs | sh -s -- --default-toolchain 1.75.0 -y
 ENV PATH=/root/.cargo/bin:$PATH
 
-# Install the colcon-cargo and colcon-ros-cargo plugins
-RUN if [ "$ROS_DISTRO" = "humble" ] ;  \
-    then pip install --upgrade pytest && pip install colcon-ros-cargo ;  \
-    else pip install --break-system-packages pytest colcon-ros-cargo ; fi
+COPY src/ros2_rust/docker/install_colcon_plugins.sh /
+RUN ./install_colcon_plugins.sh
+
+COPY src/ros2_rust/docker/rosidl_rust_setup.sh /
+RUN ./rosidl_rust_setup.sh
 
 RUN mkdir -p /workspace && echo "Did you forget to mount the repository into the Docker container?" > /workspace/HELLO.txt
 WORKDIR /workspace
+
+COPY src/ros2_rust/docker/rosidl_rust_entrypoint.sh /
+ENTRYPOINT ["/rosidl_rust_entrypoint.sh"]
+CMD ["/bin/bash"]

docker/install_colcon_plugins.sh

@@ -0,0 +1,8 @@
+#!/bin/bash
+
+if [ "$ROS_DISTRO" = "humble" ]; then
+  pip install --upgrade pytest
+  pip install colcon-ros-cargo
+else
+  pip install --break-system-packages pytest colcon-ros-cargo
+fi

docker/rosidl_rust_entrypoint.sh

@@ -0,0 +1,12 @@
+#!/bin/bash
+set -e
+
+# setup ros2 environment
+source "/opt/ros/$ROS_DISTRO/setup.bash" --
+
+# If we're a distro that needs the overlay built, then source it
+if [ -f "/tmp/rosidl_rust_overlay/install/setup.bash" ]; then
+  source /tmp/rosidl_rust_overlay/install/setup.bash --
+fi
+
+exec "$@"

docker/rosidl_rust_setup.sh

@@ -0,0 +1,17 @@
+#!/bin/bash
+
+# Depending on the ROS_DISTRO, make sure we've got rosidl_generator_rs
+# sourced and available in working directory workspace
+
+if [ "$ROS_DISTRO" = "rolling" ]; then
+  apt-get update && apt-get install -y ros-$ROS_DISTRO-rosidl-generator-rs
+else
+  # Temporarily add `rosidl_rust` to an overlay, build, and source it.
+  mkdir -p /tmp/rosidl_rust_overlay/src
+  git clone https://github.com/ros2-rust/rosidl_rust /tmp/rosidl_rust_overlay/src
+
+  cd /tmp/rosidl_rust_overlay
+
+  . /opt/ros/$ROS_DISTRO/setup.sh
+  colcon build
+fi