Comment 2 for bug 1475640

So a few replies:

1. "It signals that any command cannot be considered stable." That's a bit exaggerated if not outright misleading.

2. I agree, the exit code probably shouldn't be 0. That said, it was able to retrieve the image data (so technically it did download the image data) it just didn't save it to disk or anywhere else (if you consider stdout to be saving it somewhere). An appropriate exit code could be non-zero but I don't know what the right exit code is.

3. Things don't need to be symmetric. In fact, I'd argue that symmetry that is actively harmful to a user-experience is not worth keeping. As far as I can tell, you're the only person who was relying on this behaviour. Most people, when they download a file, are spoiled by their browsers that suggest an appropriate filename via Content-Disposition headers. None of our documentation suggests this as a way to test that Glance was successfully setup, in fact, all documentation suggests uploading an image and booting it (e.g., cirros is suggested in the install guide).

4. If only all of openstack were this composable.

"Are folks open to reverting the behaviour?"

I'm not. Like I alluded to above, I think most users who were seeing image data printed to stdout were not doing it intentionally. I know that I for one have used image-download and seen the image data to stdout and uttered some unsavory words in response.