规则

  1. 以下4种格式实际下载的是同一个内容，并且都会被tag为 nginx
    • nginx:alpine
    • library/nginx:alpine
    • [docker.io/nginx:alpine](http://docker.io/nginx:alpine)
    • docker.io/library/nginx:alpine

本规则中的镜像，可以在 dockerhub.azk8s.cn/library 下载到

  1. istio/mixer:latest 与 docker.io/istio/mixer:latest 下载到相同的内容，会被tag为 istio/mixer。
    本规则中的镜像，可以在 dockerhub.azk8s.cn/istio/mixer:latest 下载到
  2. gcr.io/pause:latest 下载不到内容， k8s.gcr.io/pause:latest 和 gcr.io/google_containers/pause:latest 可以下载到，并且会按完整的名称被tag
    本规则中的镜像，可以在 gcr.azk8s.cn/google_containers/pause:latest 下载到

代码

将以下代码保存为docker.py，然后运行docker.py pull <image>即可

  1. #!/usr/bin/python
  2. # coding=utf8
  4. import os
  5. import sys
  7. DEFAULT_DOCKER_HUB_URL = "docker.io"
  8. GCR_URL = "k8s.gcr.io"
  10. mirror_map = {
  11.     "default": "dockerhub.azk8s.cn/library",
  12.     DEFAULT_DOCKER_HUB_URL: "dockerhub.azk8s.cn",
  13.     "gcr.io": "gcr.azk8s.cn",
  14.     GCR_URL: "gcr.azk8s.cn"
  15. }
  17. url_default_namespace_map = {
  18.     DEFAULT_DOCKER_HUB_URL: "library",
  19.     GCR_URL: "google_containers"
  20. }
  22. def execute_sys_cmd(cmd):
  23.     result = os.system(cmd)
  24.     if result != 0:
  25.         print(cmd + " failed.")
  26.         sys.exit(-1)
  28. def usage():
  29.     print("Usage: " + sys.argv[0] + " pull ${image}")
  30.     print("Support the following image spec:")
  31.     print("\tdocker.py pull nginx:alpine")
  32.     print("\tdocker.py pull library/nginx:alpine")
  33.     print("\tdocker.py pull docker.io/nginx:alpine")
  34.     print("\tdocker.py pull docker.io/library/nginx:alpine")
  35.     print("\tdocker.py pull docker.io/istio/mixer")
  36.     print("\tdocker.py pull k8s.gcr.io/pause:latest")
  37.     print("\tdocker.py pull gcr.io/google_containers/pause:latest")
  39. if __name__ == "__main__":
  40.     if len(sys.argv) != 3 or sys.argv[1] != "pull":
  41.         usage()
  42.         sys.exit(-1)
  44.     image = sys.argv[2]
  45.     elements = image.split("/")
  47.     URL = ""
  48.     namespace = ""
  49.     imageName = ""
  51.     # nginx:alpine
  52.     if len(elements) == 1:
  53.         URL = DEFAULT_DOCKER_HUB_URL
  54.         namespace = url_default_namespace_map[URL]
  55.         imageName = elements[0]
  57.     if len(elements) == 2:
  58.         if "." in elements[0]:
  59.             # docker.io/nginx:alpine
  60.             # k8s.gcr.io/pause:latest
  61.             URL = elements[0]
  62.             if URL not in url_default_namespace_map:
  63.                 raise "Cannot find default namespace for " + image
  64.             namespace = url_default_namespace_map[URL]
  65.             imageName = elements[1]
  66.         else:
  67.             # library/nginx:alpine
  68.             # istio/mixer
  69.             URL = DEFAULT_DOCKER_HUB_URL
  70.             namespace = elements[0]
  71.             imageName = elements[1]
  73.     if len(elements) == 3:
  74.         URL = elements[0]
  75.         namespace = elements[1]
  76.         imageName = elements[2]
  78.     if URL not in mirror_map:
  79.         raise "Cannot find mirror for " + image
  81.     newImage = mirror_map[URL] + "/" + namespace + "/" + imageName
  82.     targetTagName = image
  83.     if URL == DEFAULT_DOCKER_HUB_URL:
  84.         if namespace == url_default_namespace_map[URL]:
  85.             targetTagName = imageName
  86.         else:
  87.             targetTagName = namespace + "/" + imageName
  89.     print("-- pulling image %s --" % image)
  91.     cmd = "docker pull {image}".format(image=newImage)
  92.     print("\t" + cmd)
  93.     execute_sys_cmd(cmd)
  95.     cmd = "docker tag {newImage} {image}".format(newImage=newImage, image=targetTagName)
  96.     print("\t" + cmd)
  97.     execute_sys_cmd(cmd)
  99.     cmd = "docker rmi {newImage}".format(newImage=newImage)
  100.     print("\t" + cmd)
  101.     execute_sys_cmd(cmd)
  103.     print("-- {image} pulling done --".format(image=image))
  104.     sys.exit(0)

```