Changes for Terraform Setup (#60)

## Summary
This makes DYNAMO_ENDPOINT and AWS_DEFAULT_REGION optional values
instead of required. It also allows the app and frontend to be on
different ip addresses, managed by kubernetes.

## Checklist
- [ ] Added Unit Tests
- [ ] Covered by existing CI
- [ ] Integration tested
- [ ] Documentation update



<!-- This is an auto-generated comment: release notes by coderabbit.ai
-->
## Summary by CodeRabbit

- **New Features**
- Enhanced handling of allowed hosts and CORS settings for better
integration with various services.
- **Bug Fixes**
- Improved flexibility in the initialization logic of the
DynamoDbClient, allowing for optional environment variables without
throwing immediate exceptions.
- **Chores**
- Updated environment variable declarations in the Dockerfile for
standardized syntax.
<!-- end of auto-generated comment: release notes by coderabbit.ai -->

Author: chewy-zlai

.github/image/Dockerfile

@@ -12,8 +12,8 @@ RUN wget -O /etc/apk/keys/amazoncorretto.rsa.pub https://apk.corretto.aws/amazon
 RUN apk add --no-cache amazon-corretto-17
 
 # java
-ENV JAVA_HOME /usr/lib/jvm/default-jvm
-ENV PATH $PATH:$JAVA_HOME/bin
+ENV JAVA_HOME=/usr/lib/jvm/default-jvm
+ENV PATH=$PATH:$JAVA_HOME/bin
 
 # sbt for scala
 RUN curl -L "https://github.com/sbt/sbt/releases/download/v1.8.2/sbt-1.8.2.tgz" | tar -xz -C /usr/local

cloud_aws/src/main/scala/ai/chronon/integrations/aws/AwsApiImpl.scala

@@ -17,16 +17,26 @@ import java.net.URI
   */
 class AwsApiImpl(conf: Map[String, String]) extends Api(conf) {
   @transient lazy val ddbClient: DynamoDbClient = {
-    val regionEnvVar =
-      sys.env.getOrElse("AWS_DEFAULT_REGION", throw new IllegalArgumentException("Missing AWS_DEFAULT_REGION env var"))
-    val dynamoEndpoint =
-      sys.env.getOrElse("DYNAMO_ENDPOINT", throw new IllegalArgumentException("Missing DYNAMO_ENDPOINT env var"))
-
-    DynamoDbClient
+    var builder = DynamoDbClient
       .builder()
-      .region(Region.of(regionEnvVar))
-      .endpointOverride(URI.create(dynamoEndpoint)) // TODO remove post docker
-      .build()
+    sys.env.get("AWS_DEFAULT_REGION").foreach { region =>
+      try {
+        builder = builder.region(Region.of(region))
+      } catch {
+        case e: IllegalArgumentException =>
+          throw new IllegalArgumentException(s"Invalid AWS region format: $region", e)
+      }
+    }
+    sys.env.get("DYNAMO_ENDPOINT").foreach { endpoint =>
+      try {
+        builder = builder.endpointOverride(URI.create(endpoint))
+      } catch {
+        case e: IllegalArgumentException =>
+          throw new IllegalArgumentException(s"Invalid DynamoDB endpoint URI: $endpoint", e)
+      }
+    }
+    builder.build()
+
   }
 
   override def genKvStore: KVStore = {

hub/conf/application.conf

@@ -11,15 +11,18 @@ play.http.parser.maxDiskBuffer=10M
 
 play.filters.hosts {
   # Allow requests to localhost:9000 and "app" for now
-  allowed = ["localhost:9000", ".app"]
+  allowed = ["localhost:9000", ".app", ${?APP_SERVICE_HOST}]
 }
 
 # Add CORS filter
 play.filters.enabled += "play.filters.cors.CORSFilter"
 
 # CORS configuration
 play.filters.cors {
-  allowedOrigins = ["http://localhost:5173", "http://localhost:3000"]
+  allowedOrigins = ["http://localhost:5173",
+                    "http://localhost:3000",
+                    "http://${?FRONTEND_SERVICE_HOST}:${?FRONTEND_SERVICE_PORT}",
+                    "https://${?FRONTEND_SERVICE_HOST}:${?FRONTEND_SERVICE_PORT}"]
   allowedHttpMethods = ["GET", "POST", "PUT", "DELETE", "OPTIONS"]
   allowedHttpHeaders = ["Accept", "Content-Type"]
 }