Extracts the MySQL datastore initialization out of `runServeCmd` and
into a new `cmd/fleet/datastore.go`. Same pattern as the prior
extractions on this issue (#44929, #45343, #45583, #46166, #46421,
#46517). Continues the path toward `serve.go` >60% coverage per the
discussion on #33370.
Three functions come out of the inline block:
- `initDatastore` — builds the shared DB connections, the datastore, and
the carve store (S3-backed when configured, otherwise the datastore
itself).
- `buildMySQLOpts` — assembles the DB options: base logger and config,
plus the optional read replica, dev SQL interceptor, and tracing.
- `evalMigrationStatus` — prints any operator guidance for the migration
status and returns whether `runServeCmd` should exit. The `os.Exit`
stays in `runServeCmd`, so the boot/refuse-to-boot decision becomes
unit-testable without the function terminating the test binary.
Behavior is preserved — `runServeCmd` calls these in the same order with
the same arguments, the migration-exit conditions are unchanged, and the
full `cmd/fleet` suite passes against MySQL + Redis. `initDatastore`
returns early after `initFatal` so it's safe when the caller's
`initFatal` doesn't terminate (the case in tests).
On test scope: `TestEvalMigrationStatus` covers every migration status
code across the dev-mode and allow-missing-migrations combinations —
that's the real decision logic. I deliberately didn't add unit tests for
`initDatastore`/`buildMySQLOpts`: their only failure paths are paranoid
`initFatal` wrapping around constructors that don't dial at construction
time, and the option builder returns opaque option closures. Those
success paths are already exercised by booting the server, so a full
datastore mock wasn't worth it for coverage's sake.
Remaining slice per the broader plan: Redis init.
**Related issue:** Refs #33370
# Checklist for submitter
- [x] Added/updated automated tests
- Changes file: not applicable — internal refactor with no user-visible
behavior change
<!-- This is an auto-generated comment: release notes by coderabbit.ai
-->
## Summary by CodeRabbit
* **Refactor**
* Reorganized database startup initialization and migration status
evaluation for improved maintainability.
* **Tests**
* Added comprehensive test coverage for database migration status
handling across various scenarios.
<!-- end of auto-generated comment: release notes by coderabbit.ai -->
Rajendra kadam
210331ba1e