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Add support for host features. - #91

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PiotrSikora wants to merge 8 commits into
proxy-wasm:mainfrom
PiotrSikora:host_features
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Add support for host features.#91
PiotrSikora wants to merge 8 commits into
proxy-wasm:mainfrom
PiotrSikora:host_features

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@PiotrSikora

@PiotrSikora PiotrSikora commented Sep 25, 2025

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The proxy_get_host_features hostcall can be used by the SDKs to
determine which features are supported by the host environment.

@PiotrSikora
Add support for host features.
a37d74b 
The `proxy_get_host_features` hostcall can be used by the SDKs to
determine which features are supported by the host environment.

Signed-off-by: Piotr Sikora <code@piotrsikora.dev>
@PiotrSikora

PiotrSikora commented Sep 26, 2025

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As mentioned in the meeting, this is still missing text about hosts generating UNIMPLEMENTED stubs for any imports starting with proxy_ to avoid linking-time issues during loading phase for imports supported/expected by guests but not implemented yet by the host.

mpwarres
mpwarres reviewed Dec 2, 2025
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Comment thread abi-versions/vNEXT/HOST_FEATURES.md Outdated
Comment thread abi-versions/vNEXT/HOST_FEATURES.md Outdated
Comment thread abi-versions/vNEXT/HOST_FEATURES.md Outdated
Comment thread abi-versions/vNEXT/HOST_FEATURES.md Outdated
@PiotrSikora
PiotrSikora marked this pull request as ready for review February 12, 2026 14:44
leonm1
leonm1 approved these changes Feb 12, 2026
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Comment thread abi-versions/vNEXT/HOST_FEATURES.md Outdated
Comment thread abi-versions/vNEXT/README.md Outdated
PiotrSikora
PiotrSikora commented Feb 17, 2026
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Comment thread abi-versions/vNEXT/README.md Outdated
Comment thread abi-versions/vNEXT/HOST_FEATURES.md Outdated
@PiotrSikora
review: stop using and/or.
2b0589c 
Signed-off-by: Piotr Sikora <code@piotrsikora.dev>
@PiotrSikora
review: clarify feature ID assignment process.
58b7325 
Signed-off-by: Piotr Sikora <code@piotrsikora.dev>
@PiotrSikora
review: add note about NOT_SUPPORTED status for hostcalls.
6af0359 
Signed-off-by: Piotr Sikora <code@piotrsikora.dev>
@PiotrSikora
review: "when 1" -> "when present".
877316b 
Signed-off-by: Piotr Sikora <code@piotrsikora.dev>
@PiotrSikora
review: be explicit about buffered/streaming callouts.
1042a69 
Signed-off-by: Piotr Sikora <code@piotrsikora.dev>
@PiotrSikora

PiotrSikora commented May 21, 2026

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@mpwarres @leonm1 I believe all comments and discussion from the meetings have been addressed here (I left the comments open, so please resolve them if you're satisfied with the answers).

@PiotrSikora PiotrSikora mentioned this pull request May 21, 2026
Merged
@PiotrSikora
PiotrSikora requested review from leonm1 and mpwarres May 21, 2026 13:16
This was linked to issues May 21, 2026
Allow hosts to advertise features/settings at runtime #55
Open
Make most/all hostcalls optional #56
Open
leonm1
leonm1 approved these changes May 21, 2026
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Looks great, thanks!

mpwarres
mpwarres approved these changes May 21, 2026
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LGTM, thanks!

leonm1
leonm1 approved these changes Aug 5, 2026
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LGTM for merging.

I propose we merge this as-is and handle guest required features in a different PR, so we can build on HOST_FEATURES.md in other PRs.

@PiotrSikora
Merge remote-tracking branch 'origin/main' into PiotrSikora/host_feat…
68f0191 
…ures

Signed-off-by: Piotr Sikora <code@piotrsikora.dev>
PiotrSikora
PiotrSikora commented Aug 11, 2026
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Comment thread abi-versions/vNEXT/README.md
- `UNIMPLEMENTED` = `12`
- `UNKNOWN_RESOURCE_ID` = `13`
- `CREATED` = `14`
- `NOT_SUPPORTED` = `15`

@PiotrSikora PiotrSikora Aug 11, 2026 •
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@leonm1 @mpwarres we now have:

  • NOT_SUPPORTED for unsupported features - either because of missing features, policy, or possibly other reasons,
  • UNIMPLEMENTED for proxy_continue_stream(Upstream) in v0.2.

Do we want to switch that UNIMPLEMENTED to more generic NOT_SUPPORTED?

@mpwarres mpwarres Aug 13, 2026

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Switching it to NOT_SUPPORTED seems desirable for uniformity, I guess the concern is about backwards compatibility? It would only be a change to the return code in the failure case, so I think that change is unlikely to be disruptive.

Is there a meaningful distinction between UNIMPLEMENTED and NOT_SUPPORTED, though? If it's just that NOT_SUPPORTED is more general, how about renaming value 12 from UNIMPLEMENTED to NOT_SUPPORTED (and maybe retaining an enum alias)?

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@mpwarres mpwarres mpwarres approved these changes
@leonm1 leonm1 leonm1 approved these changes
@martijneken martijneken Awaiting requested review from martijneken

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Make most/all hostcalls optional Allow hosts to advertise features/settings at runtime

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@PiotrSikora @mpwarres @leonm1