refactor: avoid making the stateless stack depend on the stateful sta…

…ck directly and use ARNs instead

bin/orcabus.ts

@@ -33,7 +33,7 @@ const statefulStack = new OrcaBusStatefulStack(app, 'OrcaBusStatefulStack', {
 });
 
 new OrcaBusStatelessStack(app, 'OrcaBusStatelessStack', {
-  statefulStack,
+  eventSourceDependency: statefulStack.intoEventSourceDependency(),
   ...config.stackProps.orcaBusStatelessConfig,
   ...props,
 });

lib/pipeline/orcabus-pipeline-stack.ts

@@ -103,7 +103,7 @@ class OrcaBusDeploymentStage extends cdk.Stage {
       stackProps.orcaBusStatefulConfig
     );
     new OrcaBusStatelessStack(this, 'OrcaBusStatelessStack', {
-      statefulStack,
+      eventSourceDependency: statefulStack.intoEventSourceDependency(),
       ...stackProps.orcaBusStatelessConfig,
     });
   }

lib/workload/orcabus-stateful-stack.ts

@@ -6,6 +6,7 @@ import { DatabaseConstruct, DatabaseProps } from './stateful/database/component'
 import { SecurityGroupConstruct, SecurityGroupProps } from './stateful/securitygroup/component';
 import { SchemaRegistryConstruct, SchemaRegistryProps } from './stateful/schemaregistry/component';
 import { EventSource, EventSourceProps } from './stateful/event_source/component';
+import { EventSourceDependency } from './orcabus-stateless-stack';
 
 export interface OrcaBusStatefulConfig {
   schemaRegistryProps: SchemaRegistryProps;
@@ -54,4 +55,15 @@ export class OrcaBusStatefulStack extends cdk.Stack {
       this.eventSource = new EventSource(this, 'EventSourceConstruct', props.eventSourceProps);
     }
   }
+
+  intoEventSourceDependency(): EventSourceDependency | undefined {
+    if (!this.eventSource) {
+      return;
+    }
+
+    return {
+      queueArn: this.eventSource.queueArn,
+      deadLetterQueueArn: this.eventSource.deadLetterQueueArn,
+    };
+  }
 }

lib/workload/orcabus-stateless-stack.ts

@@ -4,7 +4,6 @@ import { Construct } from 'constructs';
 import { getVpc } from './stateful/vpc/component';
 import { MultiSchemaConstructProps } from './stateless/schema/component';
 import { IVpc } from 'aws-cdk-lib/aws-ec2';
-import { OrcaBusStatefulStack } from './orcabus-stateful-stack';
 
 export interface OrcaBusStatelessConfig {
   multiSchemaConstructProps: MultiSchemaConstructProps;
@@ -16,18 +15,27 @@ export interface OrcaBusStatelessConfig {
 }
 
 /**
- * The stateless stack depends on the stateful stack. Note, this could be restricted further
- * so that not all of the stateful stack is passed to the stateless stack. E.g. for filemanager,
- * instead of passing the whole stack, it could just be the `IQueue` that filemanager depends on.
- *
- * See for reference:
- * https://blog.serverlessadvocate.com/serverless-aws-cdk-pipeline-best-practices-patterns-part-1-ab80962f109d#1913
+ * Components from the stateful event source.
+ */
+export type EventSourceDependency = {
+  /**
+   * The SQS queue ARN.
+   */
+  queueArn: string;
+  /**
+   * The dead letter queue ARN.
+   */
+  deadLetterQueueArn: string;
+};
+
+/**
+ * Properties from the stateful stack.
  */
 export interface StatefulStackDependency {
   /**
-   * The stateful stack which the stateless stack depends on.
+   * Event source prop
    */
-  statefulStack: OrcaBusStatefulStack;
+  eventSourceDependency?: EventSourceDependency;
 }
 
 export class OrcaBusStatelessStack extends cdk.Stack {

lib/workload/stateful/event_source/component.ts

@@ -7,7 +7,7 @@ import { Alarm, ComparisonOperator, MathExpression } from 'aws-cdk-lib/aws-cloud
 /**
  * Properties for defining an S3 EventBridge rule.
  */
-export type EventSourceRule = {
+export type EventSourceProps = {
   /**
    * Bucket to receive events from. If not specified, captures events from all buckets.
    */
@@ -22,12 +22,7 @@ export type EventSourceRule = {
    * A prefix of the objects that are matched when receiving events from the buckets.
    */
   prefix?: string;
-};
-
-/**
- * Props for the `EventSource` construct. An array of rules.
- */
-export type EventSourceProps = EventSourceRule[];
+}[];
 
 /**
  * A construct that defines an SQS S3 event source, along with a DLQ and CloudWatch alarms.
@@ -91,4 +86,18 @@ export class EventSource extends Construct {
       alarmDescription: 'An event has been received in the dead letter queue.',
     });
   }
+
+  /**
+   * Get the SQS queue ARN.
+   */
+  get queueArn(): string {
+    return this.queue.queueArn;
+  }
+
+  /**
+   * Get the dead letter queue ARN.
+   */
+  get deadLetterQueueArn(): string {
+    return this.deadLetterQueue.queueArn;
+  }
 }