Docker: GUI 應用，Ubuntu 上如何運行呢？

• 操作系統: Ubuntu 18.04
• 運行鏡像: continuumio/anaconda3, based on debian

Step 1) 安裝 Docker

# update the apt package index
sudo apt-get update
# install packages to allow apt to use a repository over HTTPS
sudo apt-get install apt-transport-https ca-certificates curl gnupg2 software-properties-common

# add Docker’s official GPG key
curl -fsSL https://download.docker.com/linux/ubuntu/gpg | sudo apt-key add -

# set up the stable repository
sudo add-apt-repository \
  "deb [arch=amd64] https://mirrors.tuna.tsinghua.edu.cn/docker-ce/linux/ubuntu \
  $(lsb_release -cs) \
  stable"

# update the apt package index
sudo apt-get update
# install the latest version of Docker Engine and containerd
sudo apt-get install docker-ce docker-ce-cli containerd.io

允許當前非 root 用戶管理 Docker：

sudo groupadd docker
sudo usermod -aG docker $USER

參考：

• Install Docker Engine on Ubuntu:
  https://docs.docker.com/engine/install/ubuntu/
• Docker CE 清華源:
  https://mirrors.tuna.tsinghua.edu.cn/help/docker-ce/
• Post-installation steps for Linux:
  https://docs.docker.com/engine/install/linux-postinstall/

Step 2) 准備鏡像

拉取 OpenCV 鏡像，用其顯示 GUI：

docker pull joinaero/anaconda3-opencv3:1.0.0

Step 3) xhost 添加 local

$ xhost +local:docker
non-network local connections being added to access control list

Step 4) OpenCV 預覽圖片

# 運行鏡像，指明 DISPLAY
docker run -it --rm \
  --name myenv \
  -e DISPLAY \
  -e QT_X11_NO_MITSHM=1 \
  -v /tmp/.X11-unix:/tmp/.X11-unix \
  -v $HOME/.Xauthority:/root/.Xauthority \
  joinaero/anaconda3-opencv3:1.0.0

# 激活 myenv 環境
conda activate myenv

# 預覽 GoCoding.png
python - <<EOF
import cv2
while True:
  im = cv2.imread("/tmp/GoCoding.png")
  im = cv2.resize(im, (256, 256))
  cv2.imshow("GoCoding", im)
  key = cv2.waitKey(10) & 0xFF
  if key == 27 or key == ord('q'):
    break
EOF

Step 5) OpenCV 預覽相機

# docker --device 指明 video 設備
docker run -it --rm \
  --name myenv \
  -e DISPLAY \
  -e QT_X11_NO_MITSHM=1 \
  -v /tmp/.X11-unix:/tmp/.X11-unix \
  -v $HOME/.Xauthority:/root/.Xauthority \
  --device /dev/video0 \
  --device /dev/video1 \
  joinaero/anaconda3-opencv3:1.0.0

# 激活 myenv 環境
conda activate myenv

# 預覽相機圖像
python - <<EOF
import sys
import cv2
cap = cv2.VideoCapture(0)
while True:
  ret, frame = cap.read()
  if not ret:
    sys.exit("Read the next frame failed")
  cv2.imshow("GoCoding", frame)
  key = cv2.waitKey(10) & 0xFF
  if key == 27 or key == ord('q'):
    break
cap.release()
EOF

結語

Go coding!

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