Introduces an opt-in AWS Secrets Manager backend for bearer tokens,
behind the `aws` Cargo feature. Default builds (on-prem, local dev)
don't pull in the AWS SDK and don't pay its compile cost.
- New Cargo feature `aws` gates the `aws-config` + `aws-sdk-secretsmanager`
optional deps. Default features remain empty.
- New `auth::aws::SecretsManagerTokenSource` implements `TokenSource` by
fetching a JSON `{"actor_id": "token", ...}` payload from a named
Secrets Manager secret. Credentials resolve via the AWS default chain
(env, shared config, IMDSv2 instance role, ECS task role) so no
explicit plumbing is needed under an IAM role.
- New `resolve_token_source()` dispatches based on the
`OMNIGRAPH_SERVER_BEARER_TOKENS_AWS_SECRET` env var. If the var is set
but the binary was built without `--features aws`, returns a clear
rebuild instruction rather than silently falling back.
- `serve()` now uses `resolve_token_source()` and logs which source was
selected at startup.
- `parse_json_secret_payload()` is factored out as a free function so
the payload validation (trim whitespace, reject blank actor/token,
reject non-object) is unit-testable without the AWS SDK.
- New CI job `test_aws_feature` builds + tests with `--features aws`.
Not in this PR (follow-ups):
- Background refresh loop for rotation. `SecretsManagerTokenSource`
advertises `supports_refresh: true` but the AppState-level refresh
task isn't wired yet.
- Config-YAML dispatch (today the AWS source is selected via env var
only; eventually `server.bearer_tokens.source` in `omnigraph.yaml`).
Tests:
- Default-feature build: 33 lib + 41 integration + 64 openapi.
- `--features aws` build: 32 lib (one test is cfg-gated) + 41 + 64.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
