CAMEL-25011: camel-core - Saga EIP: keep the saga of an exchange in its copies

core/camel-core/src/test/java/org/apache/camel/processor/SagaExchangeCopyTest.java

@@ -0,0 +1,101 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License.  You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.apache.camel.processor;
+
+import java.util.List;
+
+import org.apache.camel.CamelExecutionException;
+import org.apache.camel.ContextTestSupport;
+import org.apache.camel.builder.RouteBuilder;
+import org.apache.camel.component.mock.MockEndpoint;
+import org.apache.camel.model.SagaPropagation;
+import org.apache.camel.saga.InMemorySagaService;
+import org.junit.jupiter.api.Test;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertThrows;
+
+/**
+ * The exchanges created by split and multicast are copies of the exchange of the saga, and belong to the same saga.
+ */
+class SagaExchangeCopyTest extends ContextTestSupport {
+
+    @Test
+    void testSplitMandatoryStepsJoinSaga() throws Exception {
+        assertItemsCompensated("direct:split", 3);
+    }
+
+    @Test
+    void testMulticastRequiredStepsJoinSaga() throws Exception {
+        assertItemsCompensated("direct:multicast", 2);
+    }
+
+    @Test
+    void testStepAfterMulticastJoinsSaga() throws Exception {
+        // the multicast copies the result of its last copy back to the exchange, which must keep the saga
+        assertItemsCompensated("direct:after-multicast", 1);
+    }
+
+    private void assertItemsCompensated(String uri, int items) throws Exception {
+        getMockEndpoint("mock:compensate").expectedMessageCount(1);
+        getMockEndpoint("mock:item").expectedMessageCount(items);
+        getMockEndpoint("mock:compensate-item").expectedMessageCount(items);
+        getMockEndpoint("mock:complete-item").expectedMessageCount(0);
+
+        CamelExecutionException ex
+                = assertThrows(CamelExecutionException.class, () -> template.sendBody(uri, List.of("a", "b", "c")));
+
+        MockEndpoint.assertIsSatisfied(context);
+        assertEquals("payment declined", ex.getCause().getMessage());
+    }
+
+    @Override
+    protected RouteBuilder createRouteBuilder() {
+        return new RouteBuilder() {
+            @Override
+            public void configure() throws Exception {
+                context.addService(new InMemorySagaService());
+
+                from("direct:split")
+                        .saga().compensation("mock:compensate")
+                        .split(body()).to("direct:mandatory-item").end()
+                        .throwException(new IllegalStateException("payment declined"));
+
+                from("direct:multicast")
+                        .saga().compensation("mock:compensate")
+                        .multicast().to("direct:required-item", "direct:required-item").end()
+                        .throwException(new IllegalStateException("payment declined"));
+
+                from("direct:after-multicast")
+                        .saga().compensation("mock:compensate")
+                        .multicast().to("mock:a", "mock:b").end()
+                        .to("direct:mandatory-item")
+                        .throwException(new IllegalStateException("payment declined"));
+
+                from("direct:mandatory-item")
+                        .saga().propagation(SagaPropagation.MANDATORY)
+                        .compensation("mock:compensate-item").completion("mock:complete-item")
+                        .to("mock:item");
+
+                from("direct:required-item")
+                        .saga().propagation(SagaPropagation.REQUIRED)
+                        .compensation("mock:compensate-item").completion("mock:complete-item")
+                        .to("mock:item");
+            }
+        };
+    }
+}

core/camel-support/src/main/java/org/apache/camel/support/AbstractExchange.java

@@ -143,6 +143,8 @@ protected AbstractExchange(AbstractExchange parent) {
         this.rollbackOnly = parent.rollbackOnly;
         this.rollbackOnlyLast = parent.rollbackOnlyLast;
         this.routeStop = parent.routeStop;
+        // a copy (such as a split, multicast or wire tap exchange) belongs to the same saga
+        this.sagaLongRunningAction = parent.sagaLongRunningAction;
 
         if (parent.hasVariables()) {
             if (this.variableRepository == null) {