Closes the SaaS-side gap that PR-A acknowledged but didn't fix: SaaS
workspaces have no persistent /configs volume, so the platform_inbound_secret
that PR-A's provisioner wrote at workspace creation never reaches the
runtime. Without this, even after the entire RFC #2312 stack lands,
SaaS chat upload would 401 (workspace fails-closed when /configs/.platform_inbound_secret
is missing).
Solution: return the secret in the /registry/register response body
on every register call. The runtime extracts it and persists to
/configs/.platform_inbound_secret at mode 0600. Idempotent — Docker-
mode workspaces also receive it and overwrite the value the provisioner
already wrote (same value until rotation).
Why on every register, not just first-register:
* SaaS containers can be restarted (deploys, drains, EBS detach/
re-attach) — /configs is rebuilt empty on each fresh start.
* The auth_token is "issue once" because re-issuing rotates and
invalidates the previous one. The inbound secret has no rotation
flow yet (#2318) so re-sending the same value is harmless.
* Eliminates the bootstrap window where a restarted SaaS workspace
has no inbound secret on disk and would 401 every platform call.
Changes:
* workspace-server/internal/handlers/registry.go — Register handler
reads workspaces.platform_inbound_secret via wsauth.ReadPlatformInboundSecret
and includes it in the response body. Legacy workspaces (NULL
column) get a successful registration with the field omitted.
* workspace-server/internal/handlers/registry_test.go — two new tests:
- TestRegister_ReturnsPlatformInboundSecret_RFC2312_PRF: secret
present in DB → secret in response, alongside auth_token.
- TestRegister_NoInboundSecret_OmitsField: NULL column → field
omitted, registration still 200.
* workspace/platform_inbound_auth.py — adds save_inbound_secret(secret).
Atomic write via tmp + os.replace, mode 0600 from os.open(O_CREAT,
0o600) so a concurrent reader never sees 0644-default. Resets the
in-process cache after write so the next get_inbound_secret() returns
the freshly-written value (rotation-safe when it lands).
* workspace/main.py — register-response handler extracts
platform_inbound_secret alongside auth_token and persists via
save_inbound_secret. Mirrors the existing save_token pattern.
* workspace/tests/test_platform_inbound_auth.py — 6 new tests for
save_inbound_secret: writes file, mode 0600, overwrite-existing,
cache invalidation after save, empty-input no-op, parent-dir creation
for fresh installs.
Test results:
* go test ./internal/handlers/ ./internal/wsauth/ — all green
* pytest workspace/tests/ — 1272 passed (was 1266 before this PR)
Refs #2312 (parent RFC), #2308 (chat upload 503 incident).
Stacks: PR-A #2313 → PR-B #2314 → PR-C #2315 → this PR.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
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