code review comments

Author: dheeraj-mummareddy

serverless/README.md

@@ -18,21 +18,33 @@ Following are optimization katas you should be aware of while building a serverl
 applications
 
 * The Lean function
-    * Concise logic
-    * Efficient/single purpose code
-    * ephemeral environment
+    * Concise logic - Use functions to transform, not transport (utilize some of the 
+    integration available from the provider to transport), and make sure you read only
+     what you need
+    * Efficient/single purpose code - avoid conditional/routing logic and break down 
+    into individual functions, avoid "fat"/monolithic functions and control the 
+    dependencies in the function deployment package to reduce the load time for your 
+    function
+    * ephemeral environment - Utilize container start for expensive initializations
 * Eventful Invocations
-    * Succinct payloads
-    * resilient routing
-    * concurrent execution
+    * Succinct payloads - Scrutinize the event as much as possible, and watch for 
+    payload constraints (async - 128K)
+    * resilient routing - Understand retry policies and leverage dead letter queues 
+    (SQS or SNS for replays) and remember retries count as invocations
+    * concurrent execution - lambda thinks of it's scale in terms of concurrency and 
+    its not request based/duration based. Lambda will spin up the number of instances 
+    based on the request. 
 * Coordinated calls
-    * Decoupled via APIs
-    * scale-matched downstream
-    * secured
+    * Decoupled via APIs - best practice to setup your application is to have API's as
+     contracts that ensures separation of concerns
+    * scale-matched downstream - make sure when Lambda is calling downstream 
+    components, you are matching scale configuration to it (by specifying max 
+    concurrency based on downstream services)
+    * secured - Always ask a question, do I need a VPC?
 * Serviceful operations
-    * Automated operations
-    * monitored applications
-    * Innovation mindset
+    * Automated - use automated tools to manage and maintain the stack 
+    * monitored applications - use monitoring services to get holistic view of your 
+    serverless applications
 
 ## Intent
 
@@ -84,7 +96,8 @@ database service also provided by Amazon.
 
 ## AWS lambda function implementation
 
-AWS lambda SDK provides pre-defined interface `com.amazonaws.services.lambda.runtime
+[https://aws.amazon.com/sdk-for-java/](AWS Lambda SDK) provides pre-defined interface 
+`com.amazonaws.services.lambda.runtime
 .RequestHandler` to implement our lambda function. 
 
 ```java
@@ -123,9 +136,9 @@ dependencies of the function.
 
 Based on the configuration in `serverless.yml` serverless framework creates following 
 resources
-* cloud formation stack for S3 (ServerlessDeploymentBucket)
+* CloudFormation stack for S3 (ServerlessDeploymentBucket)
 * IAM Role (IamRoleLambdaExecution)
-* cloud watch (log groups)
+* CloudWatch (log groups)
 * API Gateway (ApiGatewayRestApi) 
 * Lambda function
 * DynamoDB collection

serverless/src/main/java/com/iluwatar/serverless/baas/model/Address.java

@@ -6,7 +6,7 @@
 import java.io.Serializable;
 
 /**
- * Address Object
+ * Address class
  * Created by dheeraj.mummarareddy on 3/4/18.
  */
 @DynamoDBDocument

serverless/src/main/java/com/iluwatar/serverless/baas/model/Person.java

@@ -9,7 +9,7 @@
 import java.io.Serializable;
 
 /**
- * Person Request
+ * Person class
  * Created by dheeraj.mummarareddy on 3/4/18.
  */
 @DynamoDBTable(tableName = "persons")

serverless/src/test/java/com/illuwatar/serverless/baas/api/FindPersonApiHandlerTest.java

@@ -19,6 +19,7 @@
 import static org.mockito.Mockito.verify;
 
 /**
+ * Unit tests for FindPersonApiHandler
  * Created by dheeraj.mummar on 3/5/18.
  */
 @RunWith(MockitoJUnitRunner.class)

serverless/src/test/java/com/illuwatar/serverless/baas/api/SavePersonApiHandlerTest.java

@@ -19,6 +19,7 @@
 import static org.mockito.Mockito.*;
 
 /**
+ * Unit tests for SavePersonApiHandler
  * Created by dheeraj.mummar on 3/4/18.
  */
 @RunWith(MockitoJUnitRunner.class)

serverless/src/test/java/com/iluwatar/serverless/faas/api/LambdaInfoApiHandlerTest.java

@@ -33,7 +33,7 @@
 import static org.mockito.Mockito.when;
 
 /**
- * LambdaInfoApiHandlerTest
+ * Unit tests for LambdaInfoApiHandler
  */
 @RunWith(MockitoJUnitRunner.class)
 public class LambdaInfoApiHandlerTest {