Unmanagement ideas

[ctheune]

We talked about the potential to improve the "unmanagement" story by allowing components to storing "uninstall receipts" and execute any uninstall receipts that are not "claimed" by a component during a run.

I think we don't have an issue for this yet, so here it is!

Also, I just stumbled over this issue that might be benefit from unmanagement: https://yt.flyingcircus.io/issue/FC-30068/symlink-and-cleanup-no-working-as-expected

[ctheune]

There's also another instance where unmanagement would have reduced the complexity of a change massively:
https://gitlab.flyingcircus.io/flyingcircus/fc.directory.deployment/-/merge_requests/65

[PhilTaken]

A similar approach for files might be temporary states, where intermediate files are stored in a temp directory.
Archives for example, where you only require the contents of the archive, not the archive itself, could be downloaded to a temporary location, unpacked there and subsequently deleted without requiring the user to manage the download location or the deletion of the archive manually.

In python pseudo-code this might look like

with S3Download(...) as archive:
    extract(archive, inplace=True)
    copy(f"{archive}/README.txt", f"{workdir}/README.txt")

# the archive is being deleted right after the copy or exists only in `/tmp`

I am not sure how well that would fit the batou configure-verify-update model though, maybe a wrapper component like

self += TempDir(S3Download(...))
self.temp_archive = self._
...

could work better?

[frlan]

We just came along an idea

• Adding an unmanage() method aside of configure(), verify(), update() where one can write down cod that is executed on removing time
• During deployment batou might know what is missing compared to n-1 and executing the unmanage() code
• Introducing subfolders with deployment versions at target so e.g. the deployment folder could look like

├── code
│   ├── current
│   │   ├── components
│   │   │   ├── apache
│   │   │   ├── nginx
│   │   │   └── postgresql
│   │   └── environments
│   │       ├── production
│   │       └── staging
│   └── last
│       ├── components
│       │   ├── apache
│       │   ├── nginx
│       │   └── postgresql
│       └── environments
│           ├── production
│           └── staging
└── work
    ├── apache
    └── nginx
        └── docroot

[ctheune]

Yeah, that's a variation on the "uninstall recipe" which is a bit more generic.