Add DynamoDBHistoryAutoIncrement class for version control in DynamoDB

jest-dynamodb-config.js

@@ -17,6 +17,18 @@ const config = {
       KeySchema: [{ AttributeName: 'widgetID', KeyType: 'HASH' }],
       TableName: 'widgets',
     },
+    {
+      BillingMode: 'PAY_PER_REQUEST',
+      AttributeDefinitions: [
+        { AttributeName: 'widgetID', AttributeType: 'N' },
+        { AttributeName: 'version', AttributeType: 'N' },
+      ],
+      KeySchema: [
+        { AttributeName: 'widgetID', KeyType: 'HASH' },
+        { AttributeName: 'version', KeyType: 'RANGE' },
+      ],
+      TableName: 'widgetHistory',
+    },
   ],
   installerConfig: {
     installPath: './dynamodb_local_latest',

src/index.ts

@@ -139,3 +139,88 @@ export class DynamoDBAutoIncrement extends BaseDynamoDBAutoIncrement {
     return { puts, nextCounter }
   }
 }
+
+/**
+ * Update a history table with an auto-incrementing attribute value in DynamoDB
+ *
+ * @example
+ * ```
+ * import { DynamoDB } from '@aws-sdk/client-dynamodb'
+ * import { DynamoDBDocument } from '@aws-sdk/lib-dynamodb'
+ * import { DynamoDBHistoryAutoIncrement } from '@nasa-gcn/dynamodb-autoincrement'
+ *
+ * const client = new DynamoDB({})
+ * const doc = DynamoDBDocument.from(client)
+ *
+ * const autoIncrementHistory = DynamoDBHistoryAutoIncrement({
+ *   doc,
+ *   counterTableName: 'widgets', // The table storing the current item
+ *   counterTableKey: {
+ *     widgetID: 42 // ID of the item to be updated
+ *   },
+ *   attributeName: 'version',
+ *   tableName: 'widgetsHistory', // The table storing the history of items in
+ *   initialValue: 1,
+ * })
+ *
+ * const latestVersionNumber = await autoIncrementHistory.put({
+ *   widgetName: 'A new name for this item',
+ *   costDollars: 199.99,
+ * })
+ * ```
+ */
+export class DynamoDBHistoryAutoIncrement extends BaseDynamoDBAutoIncrement {
+  protected async next(item: Record<string, NativeAttributeValue>) {
+    let nextCounter
+
+    const existingItem = (
+      await this.props.doc.get({
+        TableName: this.props.counterTableName,
+        Key: this.props.counterTableKey,
+      })
+    ).Item
+
+    const counter: number | undefined = existingItem?.[this.props.attributeName]
+
+    if (counter === undefined) {
+      nextCounter = this.props.initialValue
+
+      // Existing item didn't have a version, so give it one
+      if (existingItem) {
+        existingItem[this.props.attributeName] = nextCounter
+        nextCounter += 1
+      }
+    } else {
+      nextCounter = counter + 1
+    }
+
+    const puts: PutCommandInput[] = [
+      {
+        ConditionExpression: 'attribute_not_exists(#counter)',
+        ExpressionAttributeNames: {
+          '#counter': this.props.attributeName,
+        },
+        Item: existingItem,
+        TableName: this.props.tableName,
+      },
+      {
+        ConditionExpression:
+          'attribute_not_exists(#counter) OR #counter <> :counter',
+        ExpressionAttributeNames: {
+          '#counter': this.props.attributeName,
+        },
+        ExpressionAttributeValues: {
+          ':counter': nextCounter,
+        },
+        Item: {
+          ...item,
+          ...this.props.counterTableKey,
+          [this.props.attributeName]: nextCounter,
+        },
+        TableName: this.props.counterTableName,
+      },
+    ]
+
+    return { puts, nextCounter }
+  }
+}

src/test.ts

@@ -4,10 +4,11 @@ import {
 } from '@aws-sdk/client-dynamodb'
 import { DynamoDBDocument } from '@aws-sdk/lib-dynamodb'
 import type { DynamoDBAutoIncrementProps } from '.'
-import { DynamoDBAutoIncrement } from '.'
+import { DynamoDBAutoIncrement, DynamoDBHistoryAutoIncrement } from '.'
 
 let doc: DynamoDBDocument
 let autoincrement: DynamoDBAutoIncrement
+let autoincrementVersion: DynamoDBHistoryAutoIncrement
 let autoincrementDangerously: DynamoDBAutoIncrement
 const N = 20
 
@@ -31,6 +32,17 @@ beforeAll(async () => {
     initialValue: 1,
   }
   autoincrement = new DynamoDBAutoIncrement(options)
+  const versioningOptions: DynamoDBAutoIncrementProps = {
+    doc,
+    counterTableName: 'widgets',
+    counterTableKey: {
+      widgetID: 1,
+    },
+    attributeName: 'version',
+    tableName: 'widgetHistory',
+    initialValue: 1,
+  }
+  autoincrementVersion = new DynamoDBHistoryAutoIncrement(versioningOptions)
   autoincrementDangerously = new DynamoDBAutoIncrement({
     ...options,
     dangerously: true,
@@ -43,18 +55,49 @@ afterEach(async () => {
     [
       { TableName: 'autoincrement', KeyAttributeName: 'tableName' },
       { TableName: 'widgets', KeyAttributeName: 'widgetID' },
-    ].map(
-      async ({ TableName, KeyAttributeName }) =>
-        await Promise.all(
-          ((await doc.scan({ TableName })).Items ?? []).map(
-            async ({ [KeyAttributeName]: KeyValue }) =>
-              await doc.delete({
-                TableName,
-                Key: { [KeyAttributeName]: KeyValue },
-              })
+    ]
+      .map(
+        async ({ TableName, KeyAttributeName }) =>
+          await Promise.all(
+            ((await doc.scan({ TableName })).Items ?? []).map(
+              async ({ [KeyAttributeName]: KeyValue }) =>
+                await doc.delete({
+                  TableName,
+                  Key: { [KeyAttributeName]: KeyValue },
+                })
+            )
           )
+      )
+      .concat(
+        ...[
+          {
+            TableName: 'widgetHistory',
+            PartitionKeyAttributeName: 'widgetID',
+            SortKeyAttributeName: 'version',
+          },
+        ].map(
+          async ({
+            TableName,
+            PartitionKeyAttributeName,
+            SortKeyAttributeName,
+          }) =>
+            await Promise.all(
+              ((await doc.scan({ TableName })).Items ?? []).map(
+                async ({
+                  [PartitionKeyAttributeName]: KeyValue,
+                  [SortKeyAttributeName]: SortKeyValue,
+                }) =>
+                  await doc.delete({
+                    TableName,
+                    Key: {
+                      [PartitionKeyAttributeName]: KeyValue,
+                      [SortKeyAttributeName]: SortKeyValue,
+                    },
+                  })
+              )
+            )
         )
-    )
+      )
   )
 })
 
@@ -119,3 +162,106 @@ describe('dynamoDBAutoIncrement dangerously', () => {
     ).rejects.toThrow(ConditionalCheckFailedException)
   })
 })
+
+describe('autoincrementVersion', () => {
+  test('increments version on put when attributeName field is not defined on item', async () => {
+    // Insert initial table item
+    const widgetID = 1
+    await doc.put({
+      TableName: 'widgets',
+      Item: {
+        widgetID,
+        name: 'Handy Widget',
+        description: 'Does something',
+      },
+    })
+
+    // Create new version
+    const newVersion = await autoincrementVersion.put({
+      name: 'Handy Widget',
+      description: 'Does Everything!',
+    })
+    expect(newVersion).toBe(2)
+
+    const historyItems = (
+      await doc.query({
+        TableName: 'widgetHistory',
+        KeyConditionExpression: 'widgetID = :widgetID',
+        ExpressionAttributeValues: {
+          ':widgetID': widgetID,
+        },
+      })
+    ).Items
+
+    expect(historyItems?.length).toBe(1)
+  })
+
+  test('increments version on put when attributeName field is defined on item', async () => {
+    // Insert initial table item
+    const widgetID = 1
+    const initialItem = {
+      widgetID,
+      name: 'Handy Widget',
+      description: 'Does something',
+      version: 1,
+    }
+    await doc.put({
+      TableName: 'widgets',
+      Item: initialItem,
+    })
+
+    // Create new version
+    const newVersion = await autoincrementVersion.put({
+      name: 'Handy Widget',
+      description: 'Does Everything!',
+    })
+    expect(newVersion).toBe(2)
+
+    const historyItems = (
+      await doc.query({
+        TableName: 'widgetHistory',
+        KeyConditionExpression: 'widgetID = :widgetID',
+        ExpressionAttributeValues: {
+          ':widgetID': widgetID,
+        },
+      })
+    ).Items
+
+    expect(historyItems?.length).toBe(1)
+  })
+
+  test('increments version correctly if tracked field is included in the item on update', async () => {
+    // Insert initial table item
+    const widgetID = 1
+    const initialItem = {
+      widgetID,
+      name: 'Handy Widget',
+      description: 'Does something',
+      version: 1,
+    }
+    await doc.put({
+      TableName: 'widgets',
+      Item: initialItem,
+    })
+
+    // Create new version
+    const newVersion = await autoincrementVersion.put({
+      name: 'Handy Widget',
+      description: 'Does Everything!',
+      version: 3,
+    })
+    expect(newVersion).toBe(2)
+    const latestItem = (
+      await doc.get({
+        TableName: 'widgets',
+        Key: { widgetID },
+      })
+    ).Item
+    expect(latestItem).toStrictEqual({
+      widgetID,
+      name: 'Handy Widget',
+      description: 'Does Everything!',
+      version: 2,
+    })
+  })
+})