stop image downloads to memory

 + Fixes issue with large images hogging memory
 + stream image downloads
 + output to stdout if file not specified

Change-Id: Ia01ff9b21a2dac5d0ccf2bd58a8640e88c5cbb36
Story: 2007672
Task: 39776

3 files changed, 12 insertions, 3 deletions

diff --git a/openstackclient/image/v1/image.py b/openstackclient/image/v1/image.py
index cf1d6817..64aa3fcd 100644
--- a/openstackclient/image/v1/image.py
+++ b/openstackclient/image/v1/image.py
@@ -478,7 +478,11 @@ class SaveImage(command.Command):
         image_client = self.app.client_manager.image
         image = image_client.find_image(parsed_args.image)
 
-        image_client.download_image(image.id, output=parsed_args.file)
+        output_file = parsed_args.file
+        if output_file is None:
+            output_file = getattr(sys.stdout, "buffer", sys.stdout)
+
+        image_client.download_image(image.id, stream=True, output=output_file)
 
 
 class SetImage(command.Command):
diff --git a/openstackclient/image/v2/image.py b/openstackclient/image/v2/image.py
index 4f3e9d0b..58d92f51 100644
--- a/openstackclient/image/v2/image.py
+++ b/openstackclient/image/v2/image.py
@@ -803,7 +803,11 @@ class SaveImage(command.Command):
         image_client = self.app.client_manager.image
         image = image_client.find_image(parsed_args.image)
 
-        image_client.download_image(image.id, output=parsed_args.file)
+        output_file = parsed_args.file
+        if output_file is None:
+            output_file = getattr(sys.stdout, "buffer", sys.stdout)
+
+        image_client.download_image(image.id, stream=True, output=output_file)
 
 
 class SetImage(command.Command):
diff --git a/openstackclient/tests/unit/image/v2/test_image.py b/openstackclient/tests/unit/image/v2/test_image.py
index b094817e..80e60ee8 100644
--- a/openstackclient/tests/unit/image/v2/test_image.py
+++ b/openstackclient/tests/unit/image/v2/test_image.py
@@ -1618,7 +1618,7 @@ class TestImageSave(TestImage):
 
         verifylist = [
             ('file', '/path/to/file'),
-            ('image', self.image.id)
+            ('image', self.image.id),
         ]
         parsed_args = self.check_parser(self.cmd, arglist, verifylist)
 
@@ -1626,6 +1626,7 @@ class TestImageSave(TestImage):
 
         self.client.download_image.assert_called_once_with(
             self.image.id,
+            stream=True,
             output='/path/to/file')