Make the Image status transition early

When image-import call is made, all kind of things happens before
the image status transitions to 'importing'. We should do this as early
as possible to ensure that there is no user action against the image
while it's prcessed and the user gets the info that the importing is
actually happening.

Closes-Bug: #1749525

Change-Id: I3ff9f7af2f266dd60fd3ad738b1fb9eeb6fd9fb8
(cherry picked from commit 1f4a0cc4be)

glance/async/flows/api_image_import.py

@@ -174,63 +174,6 @@ class _ImportToStore(task.Task):
         :param image_id: Glance Image ID
         :param file_path: path to the image file
         """
-        # NOTE(flaper87): There are a couple of interesting bits in the
-        # interaction between this task and the `_ImportToFS` one. I'll try
-        # to cover them in this comment.
-        #
-        # NOTE(jokke): We do not have _ImportToFS currently in this flow but
-        # I will leave Flavio's comments here as we will utilize it or fork
-        # of it after MVP.
-        #
-        # NOTE(flaper87):
-        # `_ImportToFS` downloads the image to a dedicated `work_dir` which
-        # needs to be configured in advance (please refer to the config option
-        # docs for more info). The motivation behind this is also explained in
-        # the `_ImportToFS.execute` method.
-        #
-        # Due to the fact that we have an `_ImportToFS` task which downloads
-        # the image data already, we need to be as smart as we can in this task
-        # to avoid downloading the data several times and reducing the copy or
-        # write times. There are several scenarios where the interaction
-        # between this task and `_ImportToFS` could be improved. All these
-        # scenarios assume the `_ImportToFS` task has been executed before
-        # and/or in a more abstract scenario, that `file_path` is being
-        # provided.
-        #
-        # Scenario 1: FS Store is Remote, introspection enabled,
-        # conversion disabled
-        #
-        # In this scenario, the user would benefit from having the scratch path
-        # being the same path as the fs store. Only one write would happen and
-        # an extra read will happen in order to introspect the image. Note that
-        # this read is just for the image headers and not the entire file.
-        #
-        # Scenario 2: FS Store is remote, introspection enabled,
-        # conversion enabled
-        #
-        # In this scenario, the user would benefit from having a *local* store
-        # into which the image can be converted. This will require downloading
-        # the image locally, converting it and then copying the converted image
-        # to the remote store.
-        #
-        # Scenario 3: FS Store is local, introspection enabled,
-        # conversion disabled
-        # Scenario 4: FS Store is local, introspection enabled,
-        # conversion enabled
-        #
-        # In both these scenarios the user shouldn't care if the FS
-        # store path and the work dir are the same, therefore probably
-        # benefit, about the scratch path and the FS store being the
-        # same from a performance perspective. Space wise, regardless
-        # of the scenario, the user will have to account for it in
-        # advance.
-        #
-        # Lets get to it and identify the different scenarios in the
-        # implementation
-        image = self.image_repo.get(self.image_id)
-        image.status = 'importing'
-        self.image_repo.save(image, from_state='uploading')
-
         # NOTE(flaper87): Let's dance... and fall
         #
         # Unfortunatelly, because of the way our domain layers work and
@@ -271,6 +214,7 @@ class _ImportToStore(task.Task):
         # NOTE(jokke): The different options here are kind of pointless as we
         # will need the file path anyways for our delete workflow for now.
         # For future proofing keeping this as is.
+        image = self.image_repo.get(self.image_id)
         image_import.set_image_data(image, file_path or self.uri, self.task_id)
 
         # NOTE(flaper87): We need to save the image again after the locations
@@ -403,4 +347,9 @@ def get_flow(**kwargs):
                                   image_id)
     flow.add(complete_task)
 
+    image = image_repo.get(image_id)
+    from_state = image.status
+    image.status = 'importing'
+    image_repo.save(image, from_state=from_state)
+
     return flow