Astro: carry astro-sst as @sst-community/astro-sst, for Astro 5, 6 and 7 #44

What

Carry the astro-sst adapter into this repo as packages/astro-sst, published as @sst-community/astro-sst and installed under the old name, the same way as svelte-kit-sst:

npm install astro-sst@npm:@sst-community/astro-sst

Imports stay import aws from "astro-sst", and existing instructions keep working. One package for Astro 5, 6 and 7.

Why

sst.aws.Astro needs the astro-sst adapter, and its latest release (3.1.4, May 2025) is stuck on Astro 5:

• It doesn't build on Astro 7: "applyPolyfills" is not exported by astro/app/node.
• On Astro 6 and 7 it warns that entrypointResolution: "explicit" is deprecated.
• Astro 7's advanced routing (src/fetch.ts) is ignored. astro-sst builds its app with new NodeApp(manifest), and Astro only installs src/fetch.ts when the app comes from createApp() in astro/app/entrypoint.
• A route that only fetch.ts handles gets a 404 even then, because the handler calls app.match() first and returns its own 404 when no Astro route matches, before app.render() runs.

Tested locally on Astro 7.3.5 with astro-sst 3.1.4, running the built handler with a fake API Gateway event. A patched copy (no applyPolyfills, entrypointResolution: "auto", createApp(), app.render() without the pre-check) served fetch.ts's header on /, served a fetch.ts-only route with 200, and still returned 404 for an unknown path. sst.aws.Astro read the Astro 7 build output fine. Not deployed, and only the buffered handler was tried.

Users impacted

Anyone on Astro 6 or 7 who deploys with SST, and anyone who wants Astro 7's advanced routing. What's open today:

• how to deploy astro v6? anomalyco/sst#6697 "how to deploy astro v6?" Open since 2026-04-07, 8 comments. SST said it would probably upgrade the adapter, then that it hoped to land an official AWS Astro provider, then (June) that it might do the upgrade itself. On 2026-06-23 a user wrote that Astro 7 is out and they're blocked.
• feat: support astro 6 anomalyco/astro-sst#27 "feat: support astro 6". Open since 2026-03-10, last updated 2026-09-21. By an Astro core maintainer. Moves to createApp() and entrypointResolution: "auto", with separate buffer and stream entrypoints, for Astro 6+ only (drops Astro 5). Six comments from users asking for it to be merged, one saying it blocks their work and one asking for Astro 7 support (the PR's author replied that the next major should cover 6 and 7). One commenter also points to a libheif security advisory (GHSA-g89c-p67h-r497) as a reason to leave Astro 5; I haven't checked it. It keeps the app.match() pre-check, so a fetch.ts-only route would still 404.
• how to deploy astro v6? anomalyco/astro-sst#28 "how to deploy astro v6?" Open since 2026-04-07; points at Bus: stop a stuck subscriber from freezing sst dev #27.
• Astro 5.7 Sessions API anomalyco/astro-sst#20 "Astro 5.7 Sessions API", open since 2025-04. Not part of this; noted for later.
• A question in the community Discord asking how to make Astro 7's advanced routing work with astro-sst.

There is no open issue or PR about advanced routing itself.

In this repo, the examples aws-astro, aws-astro-stream, aws-astro-container and aws-astro-redis pin astro-sst 2.x (^2.41.2 or 2.43.5), older than the 3.1.2 that sst.aws.Astro already requires.

Plan

Mirrors packages/svelte-kit-sst (#6):

1. packages/astro-sst: the adapter from anomalyco/astro-sst (MIT), with PR Bus: stop a stuck subscriber from freezing sst dev #27's changes as the base and its author credited as co-author.
   • Astro 6 and 7: entrypointResolution: "auto", createApp(), separate buffer and stream entrypoints.
   • Astro 5: keep the current NodeApp path, chosen by feature detection like the SvelteKit adapter does (no createApp in Astro 5). No applyPolyfills.
   • Render through app.render() without a match-first 404, keeping the 404.html and /404 fallbacks, so src/fetch.ts works.
2. Tests, like svelte-kit-sst's: build Astro 5, 6 and 7 apps with the adapter, bundle the handler as SST does, call it with Lambda events (buffer and stream). Cases: pages, 404, cookies (multiple set-cookie), POST body, binary, redirects, prerendered pages, src/fetch.ts on Astro 7.
3. CI: .github/workflows/astro-sst.yml, like svelte-kit-sst.yml.
4. README and CHANGELOG with the alias install; build on prepack; publishConfig.access: public.
5. Wiring in the rest of the repo:
   • pkg/global/distribution.go: add astro-sst to CommunityPackages, so sst init installs it under the old name.
   • platform/templates/astro/preset.json, www/.../start/aws/astro.mdx, README: the install command and the Astro 6/7 notes.
   • platform/src/components/aws/astro.ts: the version check and error text (it requires astro-sst 3.1.2 or later; the new package's version must pass it).
   • Examples: move the four above to the alias.

Still to decide

• The version number for the first release. svelte-kit-sst started at 3.0.0.
• Whether to keep supporting Astro 5 (the plan above does, since sst.aws.Astro users may still be on it).