Added sample showing how to apply stream transformations for events v…

…ersioning with ESDB

.github/workflows/samples_events-versioning.yml

@@ -1,4 +1,4 @@
-name: Samples - EventStoreDB Stream Metadata
+name: Samples - EventStoreDB Events Versioning
 
 on:
   # run it on push to the default repository branch

samples/events-versioning/README.md

@@ -344,9 +344,9 @@ public class EventTypeMapping {
 and use it as
 
 ```java
-final String eventTypeV1Name = "shopping_cart_initialized_v1";
-final String eventTypeV2Name = "shopping_cart_initialized_v2";
-final String eventTypeV3Name = "shopping_cart_initialized_v3";
+final String eventTypeV1Name = "shopping_cart_opened_v1";
+final String eventTypeV2Name = "shopping_cart_opened_v2";
+final String eventTypeV3Name = "shopping_cart_opened_v3";
 
 var mapping = new EventTypeMapping()
   .register(ShoppingCartInitializedWithStatus.class,
@@ -535,20 +535,22 @@ private static EventData toShoppingCartInitializedWithProducts(
   );
 
   return new EventData(
-    "shopping_cart_initialized_v2",
+    "shopping_cart_opened_v2",
     Serializer.serialize(newEvent),
     shoppingCartInitialized.metaData
   );
 }
 ```
 
-See a full sample in [StreamTransformations.cs](./src/test/java/io/eventdriven/eventsversioning/transformations/StreamTransformationsTests.java).
+See a full sample in:
+- [StreamTransformations.cs](./src/test/java/io/eventdriven/eventsversioning/transformations/StreamTransformationsTests.java).
+- [esdb/StreamTransformations.cs](./src/test/java/io/eventdriven/eventsversioning/transformations/esdb/StreamTransformationsTests.java) showing how to apply them in practice into EventStoreDB.
 
 ## Migrations
 
 You can say that, well, those patterns are not migrations. Events will stay as they were, and you'll have to keep the old structure forever. That's quite true. Still, this is fine, as typically, you should not change the past. Having precise information, even including bugs, is a valid scenario. It allows you to get insights and see the precise history. However, pragmatically you may sometimes want to have a "clean" event log with only a new schema.
 
-It appears that composing the patterns described above can support such a case. For example, if you're running EventStoreDB or Marten, you can read/subscribe to the event stream, store events in the new stream, or even a new EventStoreDB cluster or Postgres schema. Having that, you could even rewrite the whole log and switch databases once the new one caught up.
+It appears that composing the patterns described above can support such a case. For example, if you're running EventStoreDB, you can read/subscribe to the event stream, store events in the new stream, or even a new EventStoreDB cluster. Having that, you could even rewrite the whole log and switch databases once the new one caught up.
 
 I hope that those samples will show you that you can support many versioning scenarios with basic composition techniques.
 

samples/events-versioning/build.gradle

@@ -18,16 +18,13 @@ dependencies {
   // EventStoreDB client
   implementation 'com.eventstore:db-client-java:3.0.0'
 
-
-  // Postgres and JPA for read models
-  implementation 'junit:junit:4.13.2'
-
-  implementation 'org.slf4j:slf4j-log4j13:1.0.1'
+  // Logging
   implementation 'org.apache.logging.log4j:log4j-api:2.17.2'
   implementation 'org.apache.logging.log4j:log4j-core:2.17.2'
   implementation 'org.apache.logging.log4j:log4j-slf4j-impl:2.17.2'
 
   // Test frameworks
+  implementation 'junit:junit:4.13.2'
   testImplementation 'org.junit.jupiter:junit-jupiter-api:5.8.2'
   testImplementation 'org.junit.jupiter:junit-jupiter-engine:5.8.2'
   testImplementation 'org.junit.platform:junit-platform-launcher:1.8.2'

samples/events-versioning/docker-compose.yml

@@ -29,42 +29,11 @@ services:
         target: /var/log/eventstore
     networks:
       - eventstore.db
-
-  #######################################################
-  #  Postgres
-  #######################################################
-  postgres:
-      image: clkao/postgres-plv8
-      container_name: postgres
-      environment:
-          POSTGRES_PASSWORD: Password12!
-      ports:
-          - "5432:5432"
-      networks:
-          - postgres
-
-  pgadmin:
-      image: dpage/pgadmin4
-      container_name: pgadmin_container
-      environment:
-          PGADMIN_DEFAULT_EMAIL: ${PGADMIN_DEFAULT_EMAIL:[email protected]}
-          PGADMIN_DEFAULT_PASSWORD: ${PGADMIN_DEFAULT_PASSWORD:-admin}
-          PGADMIN_CONFIG_SERVER_MODE: 'False'
-      volumes:
-          - pgadmin:/var/lib/pgadmin
-      ports:
-          - "${PGADMIN_PORT:-5050}:80"
-      networks:
-          - postgres
 
 networks:
   eventstore.db:
     driver: bridge
-  postgres:
-    driver: bridge
 
 volumes:
   eventstore-volume-data:
   eventstore-volume-logs:
-  postgres:
-  pgadmin:

samples/events-versioning/src/main/resources/log4j2.xml

@@ -15,9 +15,6 @@
       <AppenderRef ref="LogToFile"/>
       <AppenderRef ref="LogToConsole"/>
     </Logger>
-    <Logger name="org.springframework.boot" level="error" additivity="false">
-      <AppenderRef ref="LogToConsole"/>
-    </Logger>
     <Root level="error">
       <AppenderRef ref="LogToFile"/>
       <AppenderRef ref="LogToConsole"/>

samples/events-versioning/src/test/java/io/eventdriven/eventsversioning/transformations/MultipleTransformationsWithDifferentEventTypesTests.java

@@ -138,9 +138,9 @@ public Optional<Object> deserialize(String eventTypeName, byte[] json) {
   @Test
   public void UpcastObjects_Should_BeForwardCompatible() {
     // Given
-    final String eventTypeV1Name = "shopping_cart_initialized_v1";
-    final String eventTypeV2Name = "shopping_cart_initialized_v2";
-    final String eventTypeV3Name = "shopping_cart_initialized_v3";
+    final String eventTypeV1Name = "shopping_cart_opened_v1";
+    final String eventTypeV2Name = "shopping_cart_opened_v2";
+    final String eventTypeV3Name = "shopping_cart_opened_v3";
 
     var mapping = new EventTypeMapping()
       .register(ShoppingCartInitializedWithStatus.class,

samples/events-versioning/src/test/java/io/eventdriven/eventsversioning/transformations/StreamTransformationsTests.java

@@ -99,7 +99,7 @@ private static EventData toShoppingCartInitializedWithProducts(
     );
 
     return new EventData(
-      "shopping_cart_initialized_v2",
+      "shopping_cart_opened_v2",
       Serializer.serialize(newEvent),
       shoppingCartInitialized.metaData
     );
@@ -208,7 +208,8 @@ public record EventEnvelope(
   public void UpcastObjects_Should_BeForwardCompatible() {
     // Given
     var mapping = new EventTypeMapping()
-      .register(ShoppingCartInitializedWithProducts.class, "shopping_cart_initialized_v2")
+      .register(ShoppingCartEvent.ShoppingCartOpened.class, "shopping_cart_opened_v2")
+      .register(ShoppingCartInitializedWithProducts.class, "shopping_cart_opened_v2")
       .register(ShoppingCartEvent.ProductItemAddedToShoppingCart.class, "product_item_added_v1")
       .register(ShoppingCartEvent.ShoppingCartConfirmed.class, "shopping_card_confirmed_v1");
 
@@ -229,7 +230,7 @@ public void UpcastObjects_Should_BeForwardCompatible() {
 
     var events = new ArrayList<>(List.of(
       new EventEnvelope(
-        "shopping_cart_initialized_v1",
+        "shopping_cart_opened_v1",
         new ShoppingCartEvent.ShoppingCartOpened(shoppingCardId, clientId),
         new EventMetadata(theSameCorrelationId)
       ),