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Spanner Migrations

rust/spanner-migrations/README.md

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Spanner Migrations

Schema migrations for Spanner database.

Adding a New Migration

  1. Create a new SQL file in migrations/:

    {version}-{description}.spanner.sql
    

    Example: 0002-create_databases.spanner.sql

    NOTE: THE MIGRATION FILE MUST HAVE ONLY ONE DDL STATEMENT AND MUST BE IDEMPOTENT.

  2. Write your Spanner DDL in the file (one statement per file).

  3. Regenerate the manifest (from rust/rust-sysdb/spanner-migrations/ directory):

    bash
    cd rust/rust-sysdb/spanner-migrations
    cargo run --bin spanner_migration -- --generate-sum
    

    This writes directly to migrations/migrations.sum.

  4. Commit both the new migration file and updated migrations.sum.

Manifest Validation

The migrations.sum file protects against:

  • Forgotten migration files during git push
  • Accidental modifications to existing migrations
  • Merge conflicts (one line per migration)

If validation fails, regenerate the manifest and commit both the migration and updated migrations.sum.

Running Migrations

bash
# Apply migrations (default mode)
cargo run --bin spanner_migration

# Validate migrations are applied
cargo run --bin spanner_migration  # with migration_mode: validate in config

File Format

  • Filename: {version}-{description}.spanner.sql

    • version: Zero-padded number (e.g., 0001, 0002)
    • description: snake_case description
    • Extension: .spanner.sql
  • Manifest: migrations.sum

    • Format: {filename} {sha256_hash}
    • Comments start with #