🛠️ 【軟體】必學的 Docker 🛠️

利用 Multi-Stage Builds 節省容量

蠻多安裝依賴項目，官方會提供兩種安裝方式，
「Install binary files」或「Build from source」。

選擇「Build from source」代表要自己下載源文件並在本地編譯。
但在過程中的編譯環境、工具，在之後的部署階段可能是不需要的。

這時就是 Multi-Stage Build 的登場時機。

Multi-Stage Builds 理念是使用多個 stage 來構建 Image。
並拷貝前面階段編譯的二進制文件至後續階段。

即便毋須降低容量，用 Multi-Stage Build 的概念來寫也會比較整潔。

1. 實際範例

整段示範代碼的邏輯：

1. 先以 tools 階段為基礎新增 depthai-builder 階段，去處理編譯問題。
2. 再同樣以 tools 為基礎構建 final 階段，並 copy depthai-build 的二進制文件。

• 多階段構建 depthai-core

  • FROM A AS B：從 Image A 或階段 A 為基礎，開始構建階段 B。
  ​################################################################################################
  ​# - DepthAI Core Build Stage
  ​#   - In this stage, we will build DepthAI Core and extract necessary binary files.
  ​################################################################################################
  ​FROM tools AS depthai-builder
  
  ​## 安裝只有編譯期間才需要的工具
  ​RUN DEBIAN_FRONTEND=noninteractive apt-get update && \
  ​	DEBIAN_FRONTEND=noninteractive apt-get install -y \
  ​	cmake \
  ​	libclang-dev \
  ​	libssl-dev \
  ​	patchelf \
  ​	&& rm -rf /var/lib/apt/lists/*
  
  ​## 這裡下載源代碼並進行編譯
  ​RUN git clone https://github.com/luxonis/depthai-core.git && \
  ​	cd depthai-core && \
  ​	git submodule update --init --recursive && \
  ​	mkdir -p build && cd build && \
  ​	cmake .. && \ 
  ​	cmake --build . --parallel $(nproc) && \
  ​	cmake --install . --prefix /usr/local && \
  ​	cd .. && cmake -S. -Bbuild -D'DEPTHAI_BUILD_EXAMPLES=ON' && \
  ​	cmake --build build
  
  ​################################################################################################
  ​# - Final Stage
  ​#   - In this stage, we will install necessary packages and copy DepthAI Core binary files.
  ​################################################################################################
  ​FROM tools AS final
  
  ​## 只 copy 編譯後的二進制文件
  ​COPY --from=depthai-builder /usr/local/lib/libdepthai-core.so* /usr/local/lib/
  ​COPY --from=depthai-builder /usr/local/include/depthai /usr/local/include/depthai
  ​COPY --from=depthai-builder /usr/local/lib/cmake/depthai /usr/local/lib/cmake/depthai
  ​
  ​# ...
  

• 平常我就習慣用多階段構建的概念寫 Dockerfile

  • 參考範例 RTAB-Map
    ​​################################################################################################
    ​​# - Base stage
    ​​#   - This stage serves as the foundational stage for all other stages.
    ​​#   - Base image: OSRF ROS Humble Desktop Full
    ​​#       - https://hub.docker.com/r/osrf/ros/tags?page=1&name=humble-desktop-full
    ​​################################################################################################
    
    ​​FROM osrf/ros:humble-desktop-full AS base
    
    ​​LABEL org.opencontainers.image.authors="[e-mail]"
    
    ​​ARG USERNAME=user
    ​​ARG USER_UID=1000
    ​​ARG USER_GID=$USER_UID
    
    ​​SHELL ["/bin/bash", "-c"]
    
    
    ​​################################################################################################
    ​​# - User Setup stage
    ​​#   - In this stage, I will create a non-root user and configure passwordless sudo.
    ​​################################################################################################
    
    ​​FROM base AS user-setup
    
    ​​## Create a non-root user
    ​​RUN groupadd --gid $USER_GID $USERNAME && \
    ​​	useradd --uid $USER_UID --gid $USER_GID -m $USERNAME -s /bin/bash && \
    ​​	apt-get update && \
    ​​	apt-get install -y sudo && \
    ​​	echo $USERNAME ALL=\(root\) NOPASSWD:ALL > /etc/sudoers.d/$USERNAME && \
    ​​	chmod 0440 /etc/sudoers.d/$USERNAME && \
    ​​	rm -rf /var/lib/apt/lists/*
    
    
    ​​################################################################################################
    ​​# - Tools Installation stage
    ​​#   - In this stage, I will install convenient tools for development.
    ​​################################################################################################
    
    ​​FROM user-setup AS tools
    
    ​​## Install necessary packages
    ​​RUN DEBIAN_FRONTEND=noninteractive apt-get update && \
    ​​	DEBIAN_FRONTEND=noninteractive apt-get install -y \
    ​​	apt-utils \
    ​​	git \
    ​​	nano \
    ​​	net-tools \
    ​​	ssh \
    ​​	usbutils \
    ​​	udev \ 
    ​​	x11-apps \ 
    ​​	&& rm -rf /var/lib/apt/lists/*
    
    
    ​​################################################################################################
    ​​# - Final stage
    ​​#   - In this stage, I will install required packages for RTAB-Map and Intel RealSense.
    ​​#   - Reference:
    ​​#       - https://github.com/introlab/rtabmap_ros/tree/humble-devel?tab=readme-ov-file#installation
    ​​#       - https://github.com/introlab/rtabmap_ros.git
    ​​################################################################################################
    
    ​​FROM tools AS final
    
    ​​## Install Intel RealSense dependencies
    ​​RUN DEBIAN_FRONTEND=noninteractive apt-get update && \
    ​​	DEBIAN_FRONTEND=noninteractive apt-get install -y \
    ​​	ros-humble-librealsense2* \
    ​​	ros-humble-realsense2-* && \
    ​​	rm -rf /var/lib/apt/lists/*
    
    ​​## Install RTAB-Map dependencies
    ​​RUN DEBIAN_FRONTEND=noninteractive apt-get update && \
    ​​	DEBIAN_FRONTEND=noninteractive apt-get install -y \
    ​​	ros-humble-rtabmap-ros && \
    ​​	rm -rf /var/lib/apt/lists/*
    
    ​​## Install foxglove-bridge
    ​​RUN DEBIAN_FRONTEND=noninteractive apt-get update && \
    ​​	DEBIAN_FRONTEND=noninteractive apt-get install -y \
    ​​	ros-humble-foxglove-bridge && \
    ​​	rm -rf /var/lib/apt/lists/*
    
    
    ​​## Set working directory
    ​​RUN echo "source /opt/ros/$ROS_DISTRO/setup.bash" >> ~/.bashrc
    ​​WORKDIR /home/slam-ws
    
    ​​## Final configurations
    ​​# USER $USERNAME
    ​​CMD ["/bin/bash"]