kandev/docs/plans/go-dev-launcher/task-02-db-backup.md

id, title, status, wave, depends_on, plan, spec

id	title	status	wave	depends_on	plan	spec
02-db-backup	Production database backup in Go	done	1		plan.md	../../specs/platform/requirements/go-dev-launcher.md

Task 02: Production database backup in Go

Port apps/cli/src/backup.ts so make dev-prod-db stays safe on the Go path.

Acceptance

• isProductionDb(path) is false only when the normalized path contains a .kandev-dev segment; everything else is treated as production.
• backupProductionDb(dbPath, homeDir, now) copies the DB to <homeDir>/.kandev/data/backups/dev-prod-db-<RFC3339-without-separators>.db, stamps the file's mtime to now so pruning is deterministic, and returns the created path; it returns an empty path and no error when the source DB does not exist.
• Pruning keeps the five newest dev-prod-db-*.db files by mtime and never touches files outside that prefix/suffix pair (notably the backend's own kandev-* and manual-* snapshot families).

Verification

Use TDD. Add apps/backend/internal/launcher/backup_test.go with an injectable homeDir and now so back-to-back calls produce distinct names without sleeping, then:

cd apps/backend && go test ./internal/launcher/ -run 'TestIsProductionDb|TestBackupProductionDb|TestPruneBackups' -race

Files

• apps/backend/internal/launcher/backup.go (new)
• apps/backend/internal/launcher/backup_test.go (new)

Inputs

• apps/cli/src/backup.ts — the reference implementation, including the comment explaining why backups always land under ~/.kandev/data/backups/ even when dbPath points elsewhere (custom KANDEV_DATABASE_PATH is advanced usage where the user owns the backup location).
• apps/cli/src/backup.test.ts — existing cases worth mirroring.

Risks

• Failing to remove one old backup must not fail the launch; failing to create the backup must. Keep the two error paths distinct.
• A plain file copy of a live SQLite DB is what the TypeScript version does and what this task reproduces; do not silently upgrade it to VACUUM INTO here — that is the backend's boot-time backup path and a different guarantee.