refactor(batch-write-single-table): renaming, documentation

Author: mumenthalers

src/dynamo/dynamo-store.ts

@@ -7,7 +7,7 @@ import { DEFAULT_TABLE_NAME_RESOLVER } from './default-table-name-resolver.const
 import { DynamoApiOperations } from './dynamo-api-operations.type'
 import { DynamoRx } from './dynamo-rx'
 import { BatchGetSingleTableRequest } from './request/batchgetsingletable/batch-get-single-table.request'
-import { BatchWriteRequest } from './request/batchwrite/batch-write.request'
+import { BatchWriteSingleTableRequest } from './request/batchwritesingletable/batch-write-single-table.request'
 import { DeleteRequest } from './request/delete/delete.request'
 import { GetRequest } from './request/get/get.request'
 import { PutRequest } from './request/put/put.request'
@@ -59,8 +59,13 @@ export class DynamoStore<T> {
     return new DeleteRequest(this.dynamoRx, this.modelClazz, this.tableName, partitionKey, sortKey)
   }
 
-  batchWriteMany(): BatchWriteRequest<T> {
-    return new BatchWriteRequest<T>(this.dynamoRx, this.modelClazz, this.tableName)
+  /**
+   * This is a special implementation of batchWriteItem request, because it only supports one table,
+   * if you wish to write items to multiple tables
+   * create an instance of BatchWriteItemInput and use store.makeRequest with it.
+   */
+  batchWrite(): BatchWriteSingleTableRequest<T> {
+    return new BatchWriteSingleTableRequest<T>(this.dynamoRx, this.modelClazz, this.tableName)
   }
 
   scan(): ScanRequest<T> {
@@ -72,8 +77,9 @@ export class DynamoStore<T> {
   }
 
   /**
-   * This is a special implementation of BatchGetItem request, because it only supports one table, if you wish to retrieve items from multiple tables
-   * get an instance of BatchGetItem request and call it there.
+   * This is a special implementation of BatchGetItem request, because it only supports one table,
+   * if you wish to retrieve items from multiple tables
+   * create an instance of BatchGetItemInput and use store.makeRequest with it.
    */
   batchGetItem(keys: any[]): BatchGetSingleTableRequest<T> {
     return new BatchGetSingleTableRequest(this.dynamoRx, this.modelClazz, this.tableName, keys)

src/dynamo/request/batchwrite/batch-write.request.spec.ts renamed to src/dynamo/request/batchwritesingletable/batch-write-single-table.request.spec.ts

@@ -5,17 +5,17 @@ import { getTableName } from '../../../../test/helper/get-table-name.function'
 import { Organization } from '../../../../test/models/organization.model'
 import { DEFAULT_SESSION_VALIDITY_ENSURER } from '../../default-session-validity-ensurer.const'
 import { DynamoRx } from '../../dynamo-rx'
-import { BatchWriteRequest } from './batch-write.request'
+import { BatchWriteSingleTableRequest } from './batch-write-single-table.request'
 
-describe('batch write many', () => {
+describe('batch write single table request', () => {
   const tableName = getTableName(Organization)
 
   let item: Organization
   let dynamoRx: DynamoRx
-  let request: BatchWriteRequest<Organization>
+  let request: BatchWriteSingleTableRequest<Organization>
 
   let nextSpyFn: () => { value: number }
-  const generatorMock = (i: number) => <any>{ next: nextSpyFn }
+  const generatorMock = () => <any>{ next: nextSpyFn }
 
   beforeEach(() => {
     item = <any>{
@@ -29,7 +29,7 @@ describe('batch write many', () => {
   describe('correct params', () => {
     beforeEach(() => {
       dynamoRx = new DynamoRx(DEFAULT_SESSION_VALIDITY_ENSURER)
-      request = new BatchWriteRequest(dynamoRx, Organization, tableName)
+      request = new BatchWriteSingleTableRequest(dynamoRx, Organization, tableName)
 
       const output: DynamoDB.BatchWriteItemOutput = {}
       spyOn(dynamoRx, 'batchWriteItem').and.returnValue(of(output))
@@ -96,7 +96,7 @@ describe('batch write many', () => {
   describe('correct backoff', () => {
     beforeEach(() => {
       dynamoRx = new DynamoRx(DEFAULT_SESSION_VALIDITY_ENSURER)
-      request = new BatchWriteRequest(dynamoRx, Organization, tableName)
+      request = new BatchWriteSingleTableRequest(dynamoRx, Organization, tableName)
 
       const output: DynamoDB.BatchWriteItemOutput = {
         UnprocessedItems: {

src/dynamo/request/batchwrite/batch-write.request.ts renamed to src/dynamo/request/batchwritesingletable/batch-write-single-table.request.ts

@@ -11,11 +11,11 @@ import { DynamoRx } from '../../../dynamo/dynamo-rx'
 import { randomExponentialBackoffTimer } from '../../../helper'
 import { Mapper } from '../../../mapper'
 import { ModelConstructor } from '../../../model/model-constructor'
-import { BatchWriteResponse } from './batch-write.response'
+import { BatchWriteSingleTableResponse } from './batch-write-single-table.response'
 
 const MAX_BATCH_WRITE_ITEMS = 25
 
-export class BatchWriteRequest<T> {
+export class BatchWriteSingleTableRequest<T> {
   private get toKey(): (item: T) => AttributeMap {
     if (!this._keyFn) {
       this._keyFn = Mapper.createToKeyFn(this.modelClazz)
@@ -42,19 +42,19 @@ export class BatchWriteRequest<T> {
     this.itemsToProcess = []
   }
 
-  delete(items: T[]): BatchWriteRequest<T> {
+  delete(items: T[]): BatchWriteSingleTableRequest<T> {
     this.itemsToProcess.push(...items.map<WriteRequest>(item => ({ DeleteRequest: { Key: this.toKey(item) } })))
     return this
   }
 
-  put(items: T[]): BatchWriteRequest<T> {
+  put(items: T[]): BatchWriteSingleTableRequest<T> {
     this.itemsToProcess.push(
       ...items.map<WriteRequest>(item => ({ PutRequest: { Item: Mapper.toDb(item, this.modelClazz) } }))
     )
     return this
   }
 
-  private execNextBatch(): Observable<BatchWriteResponse> {
+  private execNextBatch(): Observable<BatchWriteSingleTableResponse> {
     const batch = this.itemsToProcess.splice(0, MAX_BATCH_WRITE_ITEMS)
     const batchWriteItemInput: BatchWriteItemInput = {
       RequestItems: {
@@ -76,20 +76,25 @@ export class BatchWriteRequest<T> {
     )
   }
 
+  /**
+   *
+   * @param backoffTimer generator for how much timeSlots should be waited before requesting next batch. only used when capacity was exceeded. default randomExponentialBackoffTimer
+   * @param throttleTimeSlot defines how long one timeSlot is for throttling, default 1 second
+   */
   exec(backoffTimer = randomExponentialBackoffTimer, throttleTimeSlot = 1000): Observable<void> {
-    let rBoT = backoffTimer(throttleTimeSlot)
+    let rBoT = backoffTimer()
     let backoffTime = 0
     return this.execNextBatch().pipe(
-      mergeMap((r: BatchWriteResponse) => {
+      mergeMap((r: BatchWriteSingleTableResponse) => {
         if (!r.capacityExceeded) {
-          rBoT = backoffTimer(throttleTimeSlot)
+          rBoT = backoffTimer()
           backoffTime = 0
         } else {
           backoffTime = rBoT.next().value
         }
-        return of(r).pipe(delay(backoffTime))
+        return of(r).pipe(delay(backoffTime * throttleTimeSlot))
       }),
-      mergeMap((r: BatchWriteResponse) => {
+      mergeMap((r: BatchWriteSingleTableResponse) => {
         if (r.remainingItems > 0) {
           return this.exec()
         } else {

src/dynamo/request/batchwrite/batch-write.response.ts renamed to src/dynamo/request/batchwritesingletable/batch-write-single-table.response.ts

@@ -1,6 +1,6 @@
 import { ConsumedCapacityMultiple } from 'aws-sdk/clients/dynamodb'
 
-export interface BatchWriteResponse {
+export interface BatchWriteSingleTableResponse {
   remainingItems: number
   capacityExceeded: boolean
   consumedCapacity?: ConsumedCapacityMultiple

src/dynamo/request/query/query.request.ts

@@ -134,6 +134,9 @@ export class QueryRequest<T> extends Request<T, QueryRequest<T>, QueryInput, Que
     )
   }
 
+  /**
+   * fetches all pages. may uses all provisionedOutput, therefore for client side use cases rather use pagedDatasource (exec)
+   */
   execFetchAll(): Observable<T[]> {
     return fetchAll(this)
   }

src/dynamo/request/scan/scan.request.ts

@@ -68,6 +68,9 @@ export class ScanRequest<T> extends Request<T, ScanRequest<T>, ScanInput, ScanRe
     return this.dynamoRx.scan(params).pipe(map(response => response.Count!))
   }
 
+  /**
+   * fetches all pages. may uses all provisionedOutput, therefore for client side use cases rather use pagedDatasource (exec)
+   */
   execFetchAll(): Observable<T[]> {
     return fetchAll(this)
   }

src/helper/random-exponential-backoff-timer.generator.ts

@@ -1,6 +1,6 @@
-export function* randomExponentialBackoffTimer(throttleTimeSlot: number) {
+export function* randomExponentialBackoffTimer() {
   let i = 0
   while (true) {
-    yield ((Math.pow(2, Math.round(Math.random() * ++i)) - 1) / 2) * throttleTimeSlot
+    yield (Math.pow(2, Math.round(Math.random() * ++i)) - 1) / 2
   }
 }

src/mapper/mapper.ts

@@ -54,21 +54,7 @@ export class Mapper {
       /*
        * 1) get the value of the property
        */
-      const propertyDescriptor = Object.getOwnPropertyDescriptor(item, propertyKey)
-
-      // use get accessor if available otherwise use value property of descriptor
-      let propertyValue: any
-      if (propertyDescriptor) {
-        if (propertyDescriptor.get) {
-          propertyValue = propertyDescriptor.get()
-        } else {
-          propertyValue = propertyDescriptor.value
-        }
-      } else {
-        throw new Error(
-          'there is no property descriptor for item ' + JSON.stringify(item) + ' and property key ' + propertyKey
-        )
-      }
+      const propertyValue = Mapper.getPropertyValue(item, propertyKey)
 
       let attributeValue: AttributeValue | undefined | null
 
@@ -168,6 +154,10 @@ export class Mapper {
     }
   }
 
+  /**
+   * returns the function for the given ModelConstructor to create the AttributeMap with HASH (and RANGE) Key of a given item. used to delete items
+   * @param modelConstructor
+   */
   static createToKeyFn<T>(modelConstructor: ModelConstructor<T>): (item: T) => AttributeMap {
     const metadata = MetadataHelper.get(modelConstructor)
     const properties = metadata.modelOptions.properties
@@ -326,7 +316,7 @@ export class Mapper {
     return this.mapperForType.get(type.toString())!
   }
 
-  static getPropertyValue(item: any, propertyKey: PropertyKey) {
+  static getPropertyValue(item: any, propertyKey: PropertyKey): any {
     const propertyDescriptor = Object.getOwnPropertyDescriptor(item, propertyKey)
 
     // use get accessor if available otherwise use value property of descriptor