Add save_image.py (#6914)

Signed-off-by: quicksilver <zhifeng.zhang@zilliz.com>

deployments/offline/requirements.txt

@@ -0,0 +1,2 @@
+docker==5.0.0
+nested-lookup==0.2.22

deployments/offline/save_image.py

@@ -0,0 +1,42 @@
+import argparse
+import docker
+import gzip
+import yaml
+from nested_lookup import nested_lookup
+
+
+if __name__ == "__main__":
+    parser = argparse.ArgumentParser(
+        description="Save Docker image")
+
+    parser.add_argument("--manifest",
+                        required=True,
+                        help="Path to the manifest yaml")
+    arguments = parser.parse_args()
+
+
+    with open(arguments.manifest, 'r') as file:
+        template = file.read()
+    
+    images=[]
+    parts = template.split('---')
+    for p in parts:
+        y = yaml.safe_load(p)
+        matches = nested_lookup("image", y)
+        if (len(matches)):
+                images += matches
+    
+    client = docker.from_env()
+    for image_name in set(images):
+        file_name = (image_name.split(':')[0].replace("/", "-"))
+        f = gzip.open( file_name + '.tar.gz', 'wb')
+        try:
+            image = client.images.get(image_name)
+            if image.id:
+              print ("docker image \"" + image_name + "\" already exists.")
+        except docker.errors.ImageNotFound:
+            print ("docker pull " + image_name + " ...")
+            image = client.images.pull(image_name)
+        image_tar = image.save(named=True)
+        f.writelines(image_tar)
+        f.close()