feat: Carts service checks DynamoDB connectivity at startup (#537)

src/cart/src/main/java/com/amazon/sample/carts/diagnostics/DynamoFailureAnalyzer.java

@@ -0,0 +1,33 @@
+/*
+ * Copyright Amazon.com, Inc. or its affiliates. All Rights Reserved.
+ * SPDX-License-Identifier: MIT-0
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy of this
+ * software and associated documentation files (the "Software"), to deal in the Software
+ * without restriction, including without limitation the rights to use, copy, modify,
+ * merge, publish, distribute, sublicense, and/or sell copies of the Software, and to
+ * permit persons to whom the Software is furnished to do so.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED,
+ * INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A
+ * PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
+ * HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
+ * OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
+ * SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ */
+
+ package com.amazon.sample.carts.diagnostics;
+
+import org.springframework.boot.diagnostics.AbstractFailureAnalyzer;
+import org.springframework.boot.diagnostics.FailureAnalysis;
+
+import software.amazon.awssdk.services.dynamodb.model.DynamoDbException;
+
+public class DynamoFailureAnalyzer extends AbstractFailureAnalyzer<DynamoDbException> {
+    @Override
+    protected FailureAnalysis analyze(Throwable rootFailure, DynamoDbException cause) {
+        return new FailureAnalysis(
+            "An error occurred when accessing Amazon DynamoDB: \n\n"+cause.getMessage(), 
+      "Check that the DynamoDB table has been created and your IAM credentials are configured with the appropriate access.", cause);
+    }
+}

src/cart/src/main/java/com/amazon/sample/carts/services/DynamoDBCartService.java

@@ -39,8 +39,11 @@
 import java.util.List;
 import java.util.Optional;
 
+import org.springframework.boot.context.event.ApplicationReadyEvent;
+import org.springframework.context.ApplicationListener;
+
 @Slf4j
-public class DynamoDBCartService implements CartService {
+public class DynamoDBCartService implements CartService, ApplicationListener<ApplicationReadyEvent> {
 
     private final DynamoDbClient dynamoDBClient;
     private final boolean createTable;
@@ -58,6 +61,11 @@ public DynamoDBCartService(DynamoDbClient dynamoDBClient, DynamoDbEnhancedClient
         this.table = dynamoDbEnhancedClient.table(tableName, CART_TABLE_SCHEMA);
     }
 
+    @Override
+    public void onApplicationEvent(final ApplicationReadyEvent event) {
+        this.items("test");
+    }
+
     @PostConstruct
     public void init() {
         if (createTable) {

src/cart/src/main/resources/META-INF/spring.factories

@@ -0,0 +1 @@
+org.springframework.boot.diagnostics.FailureAnalyzer = com.amazon.sample.carts.diagnostics.DynamoFailureAnalyzer

src/cart/src/main/resources/application-dynamodb.yml

@@ -2,4 +2,4 @@ carts:
   dynamodb:
     endpoint:
     createTable: false
-    tableName: Items
+    tableName: Items