database-migration-devops

Safe Database Migration with Pre-Backup and Schema Validation

Applying ALTER statements to a production database without a backup is a one-way door. If the migration corrupts data or breaks the schema, you cannot roll back. This workflow takes a snapshot first, applies the migration, validates the schema matches the expected state, and only then deploys the application with updated mappings.

Workflow

database, migrationVersion
           |
           v
+--------------+     +---------------+     +-----------------------+     +------------------+
| dbm_backup   | --> | dbm_migrate   | --> | dbm_validate_schema   | --> | dbm_update_app   |
+--------------+     +---------------+     +-----------------------+     +------------------+
  BACKUP-1363          3 ALTER              schema matches,                app deployed
  success=true         statements           no data loss                   completedAt set

Workers

BackupWorker -- Takes database (default "unknown-db") and migrationVersion (default "V000"). Creates a snapshot and returns backupId: "BACKUP-1363" with success: true.

MigrateWorker -- Receives the backup output via migrateData. Applies 3 ALTER statements and returns migrate: true, alterStatements: 3.

ValidateSchemaWorker -- Receives the migration output. Confirms the schema matches the expected state with no data loss. Returns validate_schema: true.

UpdateAppWorker -- Deploys the application with the updated schema mapping. Returns update_app: true and completedAt: "2026-03-14T00:00:00Z".

Tests

28 unit tests cover backup creation, migration execution, schema validation, and app deployment.

Running

See ../../RUNNING.md for setup and execution instructions.