Publish Spin WITs to a registry

[itowlson]

In order to start making use of the target environments feature, we need the Spin WITs to be in a wkg registry. The default is the spinframework.dev registry.

We could initially publish these manually, but longer term we'll want some sort of automated process for this, either manual dispatch or triggered by a release (acknowledging that not all releases change the WITs).

[fibonacci1729]

@itowlson are you planning to pick this up? If not i can take this!

[itowlson]

@fibonacci1729 fill yer boots

[fibonacci1729]

acknowledging that not all releases change the WITs

@itowlson I'm thinking we should just initially keep the published wits in lockstep with spin releases (even if the wits don't change). To do this, we can amend the spin release action to just dispatch an event (with release version payload) to our publish-wit workflow that will:

1. Build the wit package using wasm-tools component wit ...
2. Fetch the current published wit package to get the latest version.
3. If the latest and to-be-published are in the same major track, run wasm-tools component semver-check ... to ensure that no semver-incompatible changes were made.
4. Publish using wkg publish ...

I like the idea of keeping wit package versions in lockstep with the version of the tool.

Lmk wyt

[itowlson]

I don't this we should rev the WIT package version if nothing has changed, but as ever I'm open to being talked round!

[fibonacci1729]

It's not a hill ill die on, but in the spirit of keeping things simple I think it's worth trying out for a few releases. If it's painful we can just remove the dispatch and make it a manual part of the release process if the wits changed.

[itowlson]

Okay. My fear was that it would make things more complicated. Maybe that's my lack of understanding of versions and packages speaking.

I'd also add: remember we indirect through environment TOMLs. We can, if we wish, create spin-cli:3.5/3.6/3.7 TOMLs without needing to keep revving packages. We already have heterogeneous package versions e.g. postgres, sqlite, and haven't previously revved toplevel when there was nothing new (eg no spin:up@3.3.0).

[lann]

remember we indirect through environment TOMLs.

Oh yeah that helps. This would probably push me into the "only publish changes" camp.