Return the latest logs (#417)

spring-cloud-deployer-cloudfoundry/src/main/java/org/springframework/cloud/deployer/spi/cloudfoundry/ApplicationLogAccessor.java

@@ -61,7 +61,7 @@ public String getLog(String deploymentId, Duration apiTimeout) {
         Assert.hasText(deploymentId, "id must have text and not null");
         Assert.notNull(apiTimeout, "apiTimeout must not be null");
         StringBuilder stringBuilder = new StringBuilder();
-        ReadRequest request = ReadRequest.builder().sourceId(deploymentId).limit(MAX_LOG_LIMIT).build();
+        ReadRequest request = ReadRequest.builder().sourceId(deploymentId).limit(MAX_LOG_LIMIT).descending(true).build();
         List<Log> logs = this.logCacheClient
                 .read(request)
                 .flatMapMany(this::responseToEnvelope)
@@ -75,8 +75,15 @@ public String getLog(String deploymentId, Duration apiTimeout) {
             stringBuilder.append(log.getPayloadAsText());
             stringBuilder.append(System.lineSeparator());
         });
-
-        return stringBuilder.toString();
+        String [] lines = stringBuilder.toString().split("\n");
+        StringBuilder stringBuilderReconstruct = new StringBuilder();
+        for(int i = lines.length -1  ; i >= 0  ; i--) {
+            stringBuilderReconstruct.append(lines[i]);
+            if ( i > 0 ) {
+                stringBuilderReconstruct.append("\n");
+            }
+        }
+        return stringBuilderReconstruct.toString();
     }
 
     private Flux<Log> responseToEnvelope(ReadResponse response) {

spring-cloud-deployer-cloudfoundry/src/test/java/org/springframework/cloud/deployer/spi/cloudfoundry/ApplicationLogAccessorTests.java

@@ -0,0 +1,61 @@
+/*
+ * Copyright 2023 the original author or authors.
+ *
+ * Licensed 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
+ *
+ *      https://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.springframework.cloud.deployer.spi.cloudfoundry;
+
+import org.cloudfoundry.logcache.v1.Envelope;
+import org.cloudfoundry.logcache.v1.EnvelopeBatch;
+import org.cloudfoundry.logcache.v1.Log;
+import org.cloudfoundry.logcache.v1.LogCacheClient;
+import org.cloudfoundry.logcache.v1.ReadResponse;
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.api.extension.ExtendWith;
+import org.mockito.Mock;
+import org.mockito.junit.jupiter.MockitoExtension;
+import reactor.core.publisher.Mono;
+
+import java.time.Duration;
+import java.util.Base64;
+
+import static org.assertj.core.api.AssertionsForClassTypes.assertThat;
+import static org.mockito.ArgumentMatchers.any;
+import static org.mockito.Mockito.when;
+
+@ExtendWith(MockitoExtension.class)
+public class ApplicationLogAccessorTests {
+
+    @Mock
+    private LogCacheClient logCacheClient;
+
+    @Test
+    void testDefaultCase() {
+        String sampleData = "foo\nbar\nbaz\nboo";
+        String exectedResult = "boo\nbaz\nbar\nfoo";
+        when(logCacheClient.read(any())).thenReturn(getSampleResponse(sampleData));
+        ApplicationLogAccessor applicationLogAccessor = new ApplicationLogAccessor(this.logCacheClient);
+        assertThat(applicationLogAccessor.getLog("myDeploymentId", Duration.ofSeconds(5))).isEqualTo(exectedResult);
+    }
+
+    private Mono<ReadResponse> getSampleResponse(String sampleData) {
+        Envelope envelope = Envelope.builder().log(getSampleLog(sampleData)).build();
+        EnvelopeBatch envelopeBatch = EnvelopeBatch.builder().batch(envelope).build();
+        return Mono.just(ReadResponse.builder().envelopes(envelopeBatch).build());
+    }
+
+    private Log getSampleLog(String sampleData) {
+        return Log.builder().payload(Base64.getEncoder().encodeToString(sampleData.getBytes())).build();
+    }
+}