refactor: consolidate Liquibase migrations into a single changeset per database (#50)

## Summary

- Collapse okapi's incremental Liquibase changelogs into one
`001__create_okapi_outbox_table.sql` per database — PostgreSQL 4
changesets → 1, MySQL 3 → 1. Each `changelog.xml` now includes only the
consolidated file; the per-step migration files are removed.
- Net schema for a **new** installation is unchanged (same table,
columns, both indexes); new users get the full schema from a single
changeset instead of replaying the change history.
- CHANGELOG documents the consolidation and that the `outbox:001`
checksum changes — existing installations must start on a fresh okapi
schema, or clear okapi's rows from `okapi_databasechangelog`, before
upgrading.

## Test Plan

- [x] `LiquibaseE2ETest` (PostgreSQL + MySQL Spring Boot autoconfig,
real Liquibase on Testcontainers) — 8/8 passing
- [x] Concurrency claim/purge integration tests (exercise the
consolidated schema + indexes via real INSERT/claim) — 4/4 passing
- [x] Full `./gradlew ktlintCheck` clean

Author: endrju19

CHANGELOG.md

@@ -19,6 +19,12 @@ Until `1.0.0`, breaking changes may appear in any release and are flagged with *
   default `databasechangelog` / `databasechangeloglock`. Override the new defaults
   via configuration to keep the shared-table layout (see Added below).
   ([#37](https://github.com/softwaremill/okapi/issues/37))
+- **okapi's Liquibase migrations consolidated into a single
+  `001__create_okapi_outbox_table.sql` per database.** New installations create the
+  full schema (table + indexes) from one changeset instead of replaying the change
+  history; the resulting schema is unchanged. Existing installations from an earlier
+  release: the `outbox:001` changeset checksum changed — they must start on a fresh
+  okapi schema, or clear okapi's rows from `okapi_databasechangelog`, before upgrading.
 
 ### Added
 

…pi/db/mysql/001__create_outbox_table.sql …mysql/001__create_okapi_outbox_table.sqlokapi-mysql/src/main/resources/com/softwaremill/okapi/db/mysql/001__create_outbox_table.sql renamed to okapi-mysql/src/main/resources/com/softwaremill/okapi/db/mysql/001__create_okapi_outbox_table.sql okapi-mysql/src/main/resources/com/softwaremill/okapi/db/mysql/001__create_outbox_table.sql renamed to okapi-mysql/src/main/resources/com/softwaremill/okapi/db/mysql/001__create_okapi_outbox_table.sql

@@ -15,3 +15,7 @@ CREATE TABLE IF NOT EXISTS okapi_outbox
     last_error        TEXT,
     delivery_metadata JSON         NOT NULL
 );
+
+CREATE INDEX idx_okapi_outbox_status_last_attempt ON okapi_outbox (status, last_attempt);
+
+CREATE INDEX idx_okapi_outbox_status_created_at ON okapi_outbox (status, created_at);

okapi-mysql/src/main/resources/com/softwaremill/okapi/db/mysql/002__add_purger_index.sql

@@ -3,7 +3,5 @@
                    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
                    xsi:schemaLocation="http://www.liquibase.org/xml/ns/dbchangelog
                    http://www.liquibase.org/xml/ns/dbchangelog/dbchangelog-latest.xsd">
-    <include file="001__create_outbox_table.sql" relativeToChangelogFile="true"/>
-    <include file="002__add_purger_index.sql" relativeToChangelogFile="true"/>
-    <include file="003__add_claim_index.sql" relativeToChangelogFile="true"/>
+    <include file="001__create_okapi_outbox_table.sql" relativeToChangelogFile="true"/>
 </databaseChangeLog>

okapi-mysql/src/main/resources/com/softwaremill/okapi/db/mysql/003__add_claim_index.sql

@@ -6,6 +6,7 @@ CREATE TABLE IF NOT EXISTS okapi_outbox
     id                UUID         NOT NULL PRIMARY KEY,
     message_type      VARCHAR(255) NOT NULL,
     payload           TEXT         NOT NULL,
+    delivery_type     VARCHAR(50)  NOT NULL,
     status            VARCHAR(50)  NOT NULL DEFAULT 'PENDING',
     created_at        TIMESTAMP    NOT NULL DEFAULT CURRENT_TIMESTAMP,
     updated_at        TIMESTAMP    NOT NULL DEFAULT CURRENT_TIMESTAMP,
@@ -14,3 +15,7 @@ CREATE TABLE IF NOT EXISTS okapi_outbox
     last_error        TEXT,
     delivery_metadata JSONB        NOT NULL
 );
+
+CREATE INDEX IF NOT EXISTS idx_okapi_outbox_status_last_attempt ON okapi_outbox (status, last_attempt);
+
+CREATE INDEX IF NOT EXISTS idx_okapi_outbox_status_created_at ON okapi_outbox (status, created_at);

okapi-mysql/src/main/resources/com/softwaremill/okapi/db/mysql/changelog.xml

@@ -3,8 +3,5 @@
                    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
                    xsi:schemaLocation="http://www.liquibase.org/xml/ns/dbchangelog
                    http://www.liquibase.org/xml/ns/dbchangelog/dbchangelog-latest.xsd">
-    <include file="001__create_outbox_table.sql" relativeToChangelogFile="true"/>
-    <include file="002__add_delivery_type_column.sql" relativeToChangelogFile="true"/>
-    <include file="003__add_purger_index.sql" relativeToChangelogFile="true"/>
-    <include file="004__add_claim_index.sql" relativeToChangelogFile="true"/>
+    <include file="001__create_okapi_outbox_table.sql" relativeToChangelogFile="true"/>
 </databaseChangeLog>