Bug 1093119

This is the expected behavior and it has nothing to do with ssh. `image-download` default's output is stdout. In order to avoid 'gibberishing' the terminal, you should redirect the output to a file.

Unfortunately, we can't do anything about the terminal being completely messed up after the image is dumped to stdout, AFAIK.

Flavio, this looks really bad and no where in the cli help does it say that we need to specify a file. 

can we add --file from optional to positional argument? add a default location for the stdout under /tmp in case none is supplied? or at least add a warning to the cli help?

usage: glance image-download [--file <FILE>] [--progress] <IMAGE>

Download a specific image.

Positional arguments:
  <IMAGE>        Name or ID of image to download.

Optional arguments:
  --file <FILE>  Local file to save downloaded image data to. If this is not
                 specified the image data will be written to stdout.
  --progress     Show download progress bar.
[root@puma32 ~(keystone_admin)]#

Making `--file` a positional argument wouldn't allow the user to pipe the output, so would adding a default value for `--file`

I'll investigate whether detecting a unix pipe is possible / worth it.

I don't think this is really bad. It's *always* been like this and people is/should be used to it already. That doesn't mean we can't make it better, though.

Another solution would be to add an `--stdout` CLI arg and make the client to require either that parameter or `--file`

This would be a major change in the API and I'd like to get the community feedback here first.

I should stop commenting on bugs at 1am. So, it's obviously possible to know whether the output is being redirected or not. Here's a proposal for this fix:

1. If the output is not being redirect and `--file` is not set, require `--stdout` to be passed.
2. Keep redirection behavior as-is for backwards compatibility
3. If the output is being redirected, print a warning saying that `--stdout` should be passed.
4. In future versions *always* require one of both options.

In order to know whether the output is being redirected or not, it's enough to check if `stdout` is a tty,

```
import sys

sys.stdout.isatty()
```

@Cindy, any chance you can also tackle this?

(In reply to Flavio Percoco from comment #7)
> I should stop commenting on bugs at 1am. So, it's obviously possible to know
> whether the output is being redirected or not. Here's a proposal for this
> fix:
> 
> 1. If the output is not being redirect and `--file` is not set, require
> `--stdout` to be passed.
> 2. Keep redirection behavior as-is for backwards compatibility
> 3. If the output is being redirected, print a warning saying that `--stdout`
> should be passed.
> 4. In future versions *always* require one of both options.
> 
> In order to know whether the output is being redirected or not, it's enough
> to check if `stdout` is a tty,
> 
> ```
> import sys
> 
> sys.stdout.isatty()
> ```
> 
> @Cindy, any chance you can also tackle this?

I'll look into this one.

This has been fixed upstream and I don't think it's a high-prio bug that we should dedicate any more resources on.