Learning 007: The Temporal dev server initialises only a missing database file

• Date: 2026-10-10
• Source: system-feedback
• Work item: issue-17

What happened

design.md planned to pre-create the embedded Temporal database with os.open(…, 0o600) so it would never be readable by others. The dev server treats an existing file as already set up. Given an empty one, it failed with no such table: namespaces, and the SDK reported only that the server "did not start within 5s". Unit tests with a stubbed server passed. Only the integration test against the real binary failed.

Learning

Don't create files on behalf of a third-party server. Tighten them after the server creates them, before any sensitive data is written. Prove file-mode claims against the real process, not a stub.

Action

EmbeddedTemporal tightens the database and its -wal/-shm files to 0600 before start, when the file exists, and right after start. The restart scenario asserts the real server's files end up at 0600.