Add flux release --interactive

[rndstr]

This adds an --interactive option to the release command that lets
you pick and choose which containers to update. It uses the new
containers specification in the /v9/update-manifest call.

Once the containers are selected, the release is sent off with
the constraint that the state of the containers need to be the exact
same as when the results were presented to the user. If anything changed
in the meanwhile, the whole release will not be processed.

Closes #1227

[squaremo]

Running this (on Ubuntu 18.04, in a Terminal), I see:

$ fluxctl release --interactive --all --update-all-images
Submitting dry-run release...
Handling connection for 3030
   CONTROLLER   STATUS   UPDATES

Use [Space] to deselect containers and hit [Enter] to release selected.

then on :

panic: runtime error: integer divide by zero

goroutine 1 [running]:
github.com/weaveworks/flux/update.(*Menu).cursorUp(0xc42033f8c0)
        /home/mikeb/space/cloud/go/src/github.com/weaveworks/flux/update/menu.go:257 +0x67
github.com/weaveworks/flux/update.(*Menu).Run(0xc42033f8c0, 0xc42033f9e0, 0xc42033f700)
        /home/mikeb/space/cloud/go/src/github.com/weaveworks/flux/update/menu.go:181 +0x16c
main.promptSpec(0x932520, 0xc4200b4008, 0x0, 0x0, 0xc4202d6b80, 0xc42033f710, 0x0, 0x0, 0xc4202d6b80, 0xc42033f710, ...)
        /home/mikeb/space/cloud/go/src/github.com/weaveworks/flux/cmd/fluxctl/release_cmd.go:172 +0x5b
main.(*controllerReleaseOpts).RunE(0xc4201188f0, 0xc42010b680, 0xc42036ac00, 0x0, 0x3, 0x0, 0x0)
        /home/mikeb/space/cloud/go/src/github.com/weaveworks/flux/cmd/fluxctl/release_cmd.go:152 +0x9b4
main.(*controllerReleaseOpts).RunE-fm(0xc42010b680, 0xc42036ac00, 0x0, 0x3, 0x0, 0x0)
        /home/mikeb/space/cloud/go/src/github.com/weaveworks/flux/cmd/fluxctl/release_cmd.go:45 +0x52
github.com/weaveworks/flux/vendor/github.com/spf13/cobra.(*Command).execute(0xc42010b680, 0xc42036ab70, 0x3, 0x3, 0xc42010b680, 0xc42036ab70)
        /home/mikeb/space/cloud/go/src/github.com/weaveworks/flux/vendor/github.com/spf13/cobra/command.go:698 +0x46d
github.com/weaveworks/flux/vendor/github.com/spf13/cobra.(*Command).ExecuteC(0xc42010ab40, 0xc42010ab40, 0x8fc9f0, 0x8fc900)
        /home/mikeb/space/cloud/go/src/github.com/weaveworks/flux/vendor/github.com/spf13/cobra/command.go:783 +0x2e4
main.run(0xc4200b6100, 0x4, 0x4, 0xc420094058)
        /home/mikeb/space/cloud/go/src/github.com/weaveworks/flux/cmd/fluxctl/main.go:14 +0x9d
main.main()
        /home/mikeb/space/cloud/go/src/github.com/weaveworks/flux/cmd/fluxctl/main.go:29 +0x63

The non-interactive fluxctl release also gives me an empty result, so I expect this is entirely about the case where there are no things to update.

[rndstr]

@squaremo I knew there was something left to do.. fixed.

[squaremo]

We don't currently build windows binaries for fluxctl, but it has been requested and does apparently build. It'd be a shame to undermine that.

Judging by the imports, I would expect the interactive stuff here to only work for linux; can you add a shim specific to Windows that at least says something like "Sorry, this doesn't work in Windows yet".

[squaremo]

This doesn't build for windows (try adding windows to the list of OSes in the release-bins target in the Makefile), but it looks like it could in the future: pkg/term#8

I think you'll have to funnel the interactive bit through an OS-specific file, and make the windows one return an apologetic error.

[squaremo]

On the UI itself, it is goodly simple and I like it.

It was not obvious to me what was going on to start off with, because my first attempt had only one change. But the instructions are clear enough (maybe you could mention arrow keys too). Is there a nice right-pointing arrow glyph, since we're glyphing?

There's some glitching:

$ fluxctl release -n hello --controller=deployment/helloworld --update-all-images --interactive                                                                                 
Submitting dry-run release...                                                                                                                                                   
Handling connection for 3030                                                                                                                                                    
   CONTROLLER              STATUS   UPDATESDATES                                                                                                                                
 ◉ hello:deployment/helloworld  success  helloworld: quay.io/weaveworks/helloworld:master-a000002 -> master-07a1b6b                                                             
>◯                                       sidecar: quay.io/weaveworks/sidecar:master-a000001 -> master-a000002                                                                   
                                                                                                                                                                                
Use [Space] to deselect containers and hit [Enter] to release selected. 

(the columns don't line up, and UPDATESDATES)

The "STATUS" column is a bit out of place -- what does "success" mean here? (I realise this is inherited from the dry run output, where it is also a bit odd).

[squaremo]

It works rather neatly.

The code looks fine to me -- I am a bit dubious of driving the result output and the menu through the same code, but I see why you've done it that way.

So, two changes before we can merge this:

• fix up glitches (per the comment above)
• put in a shim for Windows

[rndstr]

I tried making it run in Windows but it needs a bit more work to read a single char cross-platform. existing libraries attempt to capture the whole terminal space by clearing it which i would rather not have.

maybe you could mention arrow keys too

doing so now 👍

Is there a nice right-pointing arrow glyph, since we're glyphing?

⇒

the columns don't line up, and UPDATESDATES

tabwriter didn't like the escape sequences.

The "STATUS" column is a bit out of place -- what does "success" mean here?

success means that it is updateable. if you provide --verbose you will also see the other statuses of updates that have not been selected for various reasons. i agree it looks odd while there is no other status.

[squaremo]

success means that it is updateable. if you provide --verbose you will also see the other statuses of updates that have not been selected for various reasons. i agree it looks odd while there is no other status.

OK, ignore this one, it's not critical. (We can revisit how the results are shown, some other time)

[squaremo]

• I reckon put a space between the arrow and the toggle (possibly it's just my font scaling messing with things).
• instead of "... to deselect containers" I suggest "... to toggle updates"

Sorry to drag this out :-/

(UPDATE: I reset font scaling and the arrow still overlaps the toggle)

[rndstr]

@squaremo made the changes, PTAL