Adds intermediate "*_unbuilt" stages to support cases where we will bind-mount and rebuild anyway.

Author: amarburg

.docker/Dockerfile

@@ -46,9 +46,10 @@ RUN apt-get -q update \
 #   - Installing blue deps using pip, apt and rosdep
 #   - Installs the remaining blue dependencies from blue_robot.repos
 #   - Installs deps from rosdep for all src dependencies
-#   - colcon build
 #
-FROM ci AS robot
+# robot_unbuilt **does not** colcon build, to save time
+#
+FROM ci AS robot_unbuilt
 
 #
 # Ubuntu 24.04 "Noble", which is used as the base image for
@@ -135,11 +136,14 @@ RUN echo "if [ -f ${USER_WORKSPACE}/install/setup.bash ]; then source ${USER_WOR
     && echo "source $VIRTUAL_ENV/bin/activate" >> /home/$USERNAME/.bashrc \
     && echo "\n# Ensure colcon is run in the venv\nalias colcon='python3 -m colcon'" >> /home/$USERNAME/.bashrc
 
+# Finally, build
+FROM robot_unbuilt AS robot
 
 # Actually build workspace
 RUN . "/opt/ros/${ROS_DISTRO}/setup.sh" \
     && colcon build
 
+FROM robot_unbuilt AS desktop_unbuilt
 
 ENV DEBIAN_FRONTEND=noninteractive
 ENV GZ_VERSION=harmonic
@@ -216,12 +220,6 @@ RUN sudo apt-get -q update \
     && sudo apt-get clean -y \
     && sudo rm -rf /var/lib/apt/lists/*
 
-# For users that build this on a laptop or system with limited RAM,
-# Modify the 'colcon build' line to be 'MAKEFLAGS="-j1 -l1" colcon build'
-# This will limit the amount of RAM that colcon is allowed to use
-RUN . "/opt/ros/${ROS_DISTRO}/setup.sh" \
-    && colcon build
-
 # Setup the simulation environment variables
 RUN  <<EOT cat >> /home/$USERNAME/.bashrc
 
@@ -238,6 +236,15 @@ export GZ_SIM_SYSTEM_PLUGIN_PATH=\$HOME/ardupilot_gazebo/build:\$GZ_SIM_SYSTEM_P
 export GZ_SIM_RESOURCE_PATH=\$HOME/ardupilot_gazebo/models:\$HOME/ardupilot_gazebo/worlds:\$GZ_SIM_RESOURCE_PATH
 EOT
 
+
+FROM desktop_unbuilt AS desktop
+
+# For users that build this on a laptop or system with limited RAM,
+# Modify the 'colcon build' line to be 'MAKEFLAGS="-j1 -l1" colcon build'
+# This will limit the amount of RAM that colcon is allowed to use
+RUN . "/opt/ros/${ROS_DISTRO}/setup.sh" \
+    && colcon build
+
 FROM desktop AS desktop-nvidia
 
 # Install NVIDIA software

.docker/docker-bake.hcl

@@ -58,28 +58,39 @@ target "ci" {
   platforms = ["linux/amd64", "linux/arm64"]
 }
 
+target "robot_unbuilt" {
+  inherits = [ "ci" ]
+  target = "robot_unbuilt"
+  tags = [
+    "ghcr.io/${BLUE_GITHUB_REPO}:${BLUE_ROS_DISTRO}-robot-unbuilt"
+  ]
+
+}
+
 target "robot" {
-  inherits = [ "ci", "docker-metadata-action-robot" ]
+  inherits = [ "robot_unbuilt", "docker-metadata-action-robot" ]
   target = "robot"
   tags = [
     "ghcr.io/${BLUE_GITHUB_REPO}:${BLUE_ROS_DISTRO}-robot"
   ]
-  cache_to = [
-    "type=local,dest=.docker-cache"
+}
+
+target "desktop_unbuilt" {
+  inherits = [ "ci" ]
+  target = "desktop"
+  tags = [
+    "ghcr.io/${BLUE_GITHUB_REPO}:${BLUE_ROS_DISTRO}-desktop-unbuilt"
   ]
+  # amd64 only builds for desktop and desktop-nvidia
+  platforms = ["linux/amd64"]
 }
 
 target "desktop" {
-  inherits = [ "ci", "docker-metadata-action-desktop" ]
+  inherits = [ "desktop_unbuilt", "docker-metadata-action-desktop" ]
   target = "desktop"
   tags = [
     "ghcr.io/${BLUE_GITHUB_REPO}:${BLUE_ROS_DISTRO}-desktop"
   ]
-  cache_to = [
-    "type=local,dest=.docker-cache"
-  ]
-  # amd64 only builds for desktop and desktop-nvidia
-  platforms = ["linux/amd64"]
 }
 
 target "desktop-nvidia" {
@@ -88,7 +99,5 @@ target "desktop-nvidia" {
   tags = [
     "ghcr.io/${BLUE_GITHUB_REPO}:${BLUE_ROS_DISTRO}-desktop-nvidia"
   ]
-  cache_to = [
-    "type=local,dest=.docker-cache"
-  ]
+
 }