feat: creates dynamo table

Author: bencegadanyi1-nhs

packages/cdk/constructs/DynamoDbTable.ts

@@ -0,0 +1,53 @@
+import {Construct} from "constructs"
+import {RemovalPolicy} from "aws-cdk-lib"
+import {
+  AttributeType,
+  Billing,
+  ProjectionType,
+  TableEncryptionV2,
+  TableV2
+} from "aws-cdk-lib/aws-dynamodb"
+import {Key} from "aws-cdk-lib/aws-kms"
+
+export interface DynamoDbTableProps {
+  readonly tableName: string
+  readonly kmsKey: Key
+}
+
+export class DynamoDbTable extends Construct {
+  public readonly table: TableV2
+
+  constructor(scope: Construct, id: string, props: DynamoDbTableProps) {
+    super(scope, id)
+
+    this.table = new TableV2(this, props.tableName, {
+      tableName: props.tableName,
+      partitionKey: {
+        name: "pk",
+        type: AttributeType.STRING
+      },
+      sortKey: {
+        name: "sk",
+        type: AttributeType.STRING
+      },
+      billing: Billing.onDemand(),
+      encryption: TableEncryptionV2.customerManagedKey(props.kmsKey),
+      removalPolicy: RemovalPolicy.DESTROY,
+      pointInTimeRecoverySpecification: {
+        pointInTimeRecoveryEnabled: true
+      },
+      // TODO: discuss TTL settings
+      timeToLiveAttribute: "ttl"
+    })
+
+    // GSI for reverse lookups if needed (session_id -> thread info)
+    this.table.addGlobalSecondaryIndex({
+      indexName: "session-index",
+      partitionKey: {
+        name: "session_id",
+        type: AttributeType.STRING
+      },
+      projectionType: ProjectionType.ALL
+    })
+  }
+}

packages/cdk/resources/Storage.ts

@@ -1,6 +1,7 @@
 import {Construct} from "constructs"
 import {Key} from "aws-cdk-lib/aws-kms"
 import {S3Bucket} from "../constructs/S3Bucket"
+import {DynamoDbTable} from "../constructs/DynamoDbTable"
 
 export interface StorageProps {
   readonly stackName: string
@@ -9,6 +10,8 @@ export interface StorageProps {
 export class Storage extends Construct {
   public readonly kbDocsBucket: S3Bucket
   public readonly kbDocsKey: Key
+  public readonly conversationTable: DynamoDbTable
+  public readonly conversationKey: Key
 
   constructor(scope: Construct, id: string, props: StorageProps) {
     super(scope, id)
@@ -25,5 +28,17 @@ export class Storage extends Construct {
       kmsKey: this.kbDocsKey,
       versioned: true
     })
+
+    // create KMS key for conversation table encryption
+    this.conversationKey = new Key(this, "ConversationKey", {
+      enableKeyRotation: true,
+      description: "KMS key for encrypting conversation sessions"
+    })
+
+    // create DynamoDB table for conversation sessions
+    this.conversationTable = new DynamoDbTable(this, "ConversationTable", {
+      tableName: `${props.stackName}-conversations`,
+      kmsKey: this.conversationKey
+    })
   }
 }