feature/issue 37 okapi table prefix

[pdudzinsky]

Summary

• BREAKING: outbox domain table renamed outbox → okapi_outbox. Indexes follow (idx_okapi_outbox_*). Host applications with a pre-existing outbox table are unaffected — okapi creates its own under the okapi_ prefix.
• BREAKING: Liquibase tracking tables default to okapi_databasechangelog / okapi_databasechangeloglock, configurable via two new properties.
• New configuration: okapi.liquibase.changelog-table / okapi.liquibase.changelog-lock-table (override the new defaults to keep the shared layout). The domain-table name is fixed.

Closes #37.

Motivation

okapi's autoconfigured SpringLiquibase previously inherited Liquibase's defaults and wrote its migration history into the host application's databasechangelog / databasechangeloglock, mixing library and application records. The domain table outbox likewise collided with applications that already have a table by that name. Issue #37 proposed isolating both under an okapi_ prefix.

What changed

Concern	Before	After
Outbox domain table	outbox	okapi_outbox (fixed)
Outbox indexes	idx_outbox_*	idx_okapi_outbox_*
Liquibase changelog table	databasechangelog	okapi_databasechangelog (configurable)
Liquibase changelog lock table	databasechangeloglock	okapi_databasechangeloglock (configurable)

Configuration:

okapi:
  liquibase:
    changelog-table: okapi_databasechangelog
    changelog-lock-table: okapi_databasechangeloglock

Validation rejects blank values at startup. Domain-table name is hardcoded in PostgresOutboxStore / MysqlOutboxStore SQL — no runtime configurability for it.

Migration from 0.2.x

Existing 0.2.x deployments must take action before the first 0.3.0 startup. Two paths documented in README — Upgrading from 0.2.x:

1. Stay on legacy Liquibase changelog tables (zero-downtime opt-out for the tracking pair):

   okapi:
     liquibase:
       changelog-table: databasechangelog
       changelog-lock-table: databasechangeloglock

   The domain-table rename has no opt-out — run the SQL below regardless.

2. Rename in place (PostgreSQL syntax shown):

   ALTER TABLE outbox RENAME TO okapi_outbox;
   ALTER INDEX idx_outbox_status_last_attempt RENAME TO idx_okapi_outbox_status_last_attempt;
   ALTER INDEX idx_outbox_status_created_at  RENAME TO idx_okapi_outbox_status_created_at;
   
   CREATE TABLE okapi_databasechangelog     (LIKE databasechangelog INCLUDING ALL);
   CREATE TABLE okapi_databasechangeloglock (LIKE databasechangeloglock INCLUDING ALL);
   INSERT INTO okapi_databasechangelog
       SELECT * FROM databasechangelog WHERE filename LIKE '%com/softwaremill/okapi/%';
   INSERT INTO okapi_databasechangeloglock SELECT * FROM databasechangeloglock;
   DELETE FROM databasechangelog WHERE filename LIKE '%com/softwaremill/okapi/%';

Without one of these steps, Liquibase will see an empty changelog table on the first 0.3.0 startup and try to re-run okapi's migrations — which fails because the legacy outbox already exists while okapi now writes to okapi_outbox.

CHANGELOG.md (Keep a Changelog 1.1.0) added; covers [Unreleased] plus retrofits [0.2.0] and [0.1.0].

Test plan

• Unit — LiquibaseAutoConfigurationTest (10 tests): bean wiring (Postgres + MySQL × default + custom), validation rejection (empty/whitespace × table + lock-table), okapi.liquibase.* Spring Binder contract, init-block validation propagation through Spring binding.
• E2E (testcontainers) — LiquibaseE2ETest (4 tests): real PostgreSQL 16 + MySQL 8.0 containers verify autoconfig creates okapi_outbox + okapi_databasechangelog + okapi_databasechangeloglock on startup; custom okapi.liquibase.changelog-table actually creates the named table in DDL.
• Integration — existing *ConnectionLeakProofTest, MultiDataSourceTransactionTest, *ConcurrentClaimTest, *EndToEndTest, store contract tests adapted to okapi_outbox — all green.
• Build & lint — ./gradlew build (105 tasks) green; ./gradlew ktlintCheck clean.
• (For reviewer) Spot-check the migration SQL against your own database setup if you maintain a 0.2.x deployment.