[skyoo2003]

Summary

Completes Phase 2 — Architectural Preparation of docs/roadmap.md: the internal refactor that makes adding a second cloud provider an addition rather than a fork. No non-AWS service ships here and no AWS behaviour changes.

Related Issue

No tracking issue exists — this implements the Phase 2 checklist in docs/roadmap.md directly. Refs the roadmap, closes nothing.

Changes

Intermediate Representation — internal/codegen/ir holds the provider-neutral *ir.Model. The parser used to produce a SmithyModel that generators read directly, so the only format DevCloud could ever read was the one its type was named after. Generators now read only the IR; SmithyModel is gone.

ModelSource — internal/codegen/source.go. One interface per API description format. SmithySource is the first implementation and owns its own detection (a top-level smithy version key), so cmd/codegen hands each file to SourceFor and never names a format. A file no source claims is now an error rather than a quiet skip — the .json extension filter that used to decide that was format knowledge living in the driver.

Provider namespacing in config — service blocks can be written as providers.aws.services.*, forward-compatible with providers.azure.*. The top-level services block is the same block under its historical name and is not deprecated; providers.aws.services wins when both are written and names the loser in a warning. A block for a provider this build cannot serve loads with a warning instead of failing, so a config written for a later DevCloud still starts this one. AWS data dirs stay flat (<base>/<id>) because that layout is a 1.x guarantee; other providers nest under their own name so same-named services cannot collide.

Plugin CSP-neutrality review — ServicePlugin needs no change; the review is written up in docs/plugin-api.md. The CSP is carried by the optional ProviderScoped interface, read through plugin.ProviderOf. Making it a ServicePlugin method would have forced an edit to all 104 in-tree providers so each could state the value it already defaults to, and would have broken the v1.x contract for no gain. Startup now resolves config with cfg.ProviderService(plugin.ProviderOf(p), id).

Per-provider auth adapters — internal/auth holds one Adapter per provider, SigV4 being AWS's. The caller's claimed identity reaches every plugin via auth.FromContext and appears as a new region field on GET /devcloud/api/logs. Nothing is verified: rejecting unsigned calls would break every SDK pointed at DevCloud with placeholder credentials, which compatibility-policy.md documents as deliberate.

The adapter also removes a duplicate parse: protocol.go had its own SigV4 credential-scope reader used for routing, and now delegates — so routing and identity cannot disagree about what the caller signed for. One side effect worth noting in review: presigned URLs (X-Amz-Credential query) now yield a signing name where previously only the Authorization header did, which routes presigned non-S3 requests by scope instead of defaulting them to S3.

Test Plan

• go build ./..., go vet ./..., gofmt -l — clean
• golangci-lint run — 0 issues
• go test ./... — all packages pass
• make test-compat — 775 passed, run against the final tree. This is the check that matters for the protocol.go change.
• make codegen re-run — generated output byte-identical, no drift
• New tests: internal/codegen/source_test.go (format detection, including that an OpenAPI document is not claimed by Smithy), internal/auth/sigv4_test.go (header, presigned query, SigV2/unsigned rejection, truncated scope, context round-trip), and four internal/config tests covering both config spellings, the both-written warning, unknown-provider forward compatibility, and DEVCLOUD_SERVICES staying AWS-scoped.

Checklist

• Self-reviewed the code
• Added/updated tests
• Lint/format passes (golangci-lint run)
• Updated documentation (if applicable) — roadmap.md (Phase 2 → Complete, Phase 3 → Next), architecture.md (provider seams table, auth section, codegen pipeline), plugin-api.md (CSP-neutrality review, caller identity), configuration.md (provider namespacing), compatibility-policy.md
• Added a Changie changelog fragment for user-facing changes — 3 fragments in changes/unreleased/