.circleci/config.yml

@@ -3,7 +3,7 @@ version: 2
 defaults: &defaults
   working_directory: ~/repo
   docker:
-    - image: circleci/node:8.14.1
+    - image: circleci/node:12.18.1
 
 jobs:
   build:

.nvmrc

@@ -1 +1 @@
-8.15.0
+12.14.1

package.json

@@ -16,9 +16,9 @@
     "docs:deploy": "./deploy-docs.sh",
     "lint": "lerna run lint",
     "test": "yarn test:unit && yarn test:integration",
-    "test:unit": "jest \"(src\\/.+\\.|/)spec\\.ts$\"",
+    "test:unit": "dotenv -e test.env -- jest \"(src\\/.+\\.|/)spec\\.ts$\"",
     "test:unit:watch": "yarn run test:unit --watch",
-    "test:integration": "jest --runInBand \"bus-(core|messages|workflow).*(src\\/.+\\.|/)integration\\.ts$\""
+    "test:integration": "dotenv -e test.env -- jest --runInBand \"bus-(core|messages|workflow).*(src\\/.+\\.|/)integration\\.ts$\""
   },
   "keywords": [
     "typescript",
@@ -44,14 +44,15 @@
   ],
   "devDependencies": {
     "@node-ts/code-standards": "^0.0.10",
-    "@types/jest": "^24.0.12",
+    "@types/jest": "^26.0.4",
+    "dotenv-cli": "^3.2.0",
     "inversify": "^5.0.1",
-    "jest": "^24.7.1",
+    "jest": "^26.1.0",
     "lerna": "^3.18.4",
     "reflect-metadata": "^0.1.13",
-    "ts-jest": "^25.1.0",
-    "tslib": "^1.9.3",
-    "typescript": "^3.3.3",
+    "ts-jest": "^26.1.1",
+    "tslib": "^2.0.0",
+    "typescript": "^3.9.6",
     "vuepress": "^1.1.0",
     "vuepress-plugin-sitemap": "^2.1.2"
   }

packages/bus-core/README.md

@@ -1,6 +1,6 @@
 # @node-ts/bus-core
 
-[![Greenkeeper badge](https://badges.greenkeeper.io/node-ts/bus.svg)](https://greenkeeper.io/)
+[![Known Vulnerabilities](https://snyk.io/test/github/node-ts/bus/badge.svg)](https://snyk.io/test/github/node-ts/bus)
 [![CircleCI](https://circleci.com/gh/node-ts/bus/tree/master.svg?style=svg)](https://circleci.com/gh/node-ts/bus/tree/master)[![License: MIT](https://img.shields.io/badge/License-MIT-green.svg)](https://opensource.org/licenses/MIT)
 
 The core messaging framework. This package provides an in-memory queue and persistence by default, but is designed to be used with other @node-ts/bus-* packages that provide compatibility with other transports (SQS, RabbitMQ, Azure Queues) and persistence technologies (PostgreSQL, SQL Server, Oracle). 
@@ -29,7 +29,7 @@ export class ApplicationContainer extends Container {
 
 ## Register a message handler
 
-Messages are handled by defining and registring a handler class. Each time a message is received by the application, it will be dispatched to each of the registered handlers.
+Messages are handled by defining and registering a handler class. Each time a message is received by the application, it will be dispatched to each of the registered handlers.
 
 Define the handler:
 
@@ -105,3 +105,33 @@ addHook (): void {
   bus.off('send', callback)
 }
 ```
+
+## Failing a Message
+
+When an error is thrown whilst handling an error, the message is typically sent back to the queue so that it can be retried. 
+
+There are times when we know that a message will never succeed even if it were to be retried. In these situations we may not want to wait for our message to be retried before sending it to the dead letter queue, but instead bypass the retries and send it to the dead letter queue immediately.
+
+This can be done by calling `bus.fail()` from within the scope of a message handling context. This will instruct `@node-ts/bus` to forward the currently handled message to the dead letter queue and remove it from the service queue.
+
+## Message handling concurrency
+
+By default, `@node-ts/bus` will run with a message handling concurrency of 1. This means that only a single message will be read off the queue and processed at a time.
+
+To increase the message handling concurrency, provide your configuration like so:
+
+```typescript
+import { Container } from 'inversify'
+import { BusModule, BUS_SYMBOLS, BusConfiguration } from '@node-ts/bus-core'
+
+const concurrency = 3 // Handle up to 3 messages in parallel
+export class ApplicationContainer extends Container {
+  constructor () {
+    this.load(new BusModule())
+
+    this
+      .rebind<BusConfiguration>(BUS_SYMBOLS.BusConfiguration)
+      .toConstantValue({ concurrency })
+  }
+}
+```

packages/bus-core/package.json

@@ -1,6 +1,6 @@
 {
   "name": "@node-ts/bus-core",
-  "version": "0.5.9",
+  "version": "0.6.4",
   "description": "A service bus for message-based, distributed node applications",
   "main": "./dist/index.js",
   "types": "./dist/index.d.ts",
@@ -13,10 +13,10 @@
     "access": "public"
   },
   "dependencies": {
-    "@node-ts/bus-messages": "^0.2.3",
-    "@types/node": "^12.12.37",
+    "@node-ts/bus-messages": "^0.3.1",
+    "@types/node": "^12.12.39",
     "autobind-decorator": "^2.4.0",
-    "class-transformer": "^0.2.3",
+    "class-transformer": "^0.3.1",
     "inversify": "^5.0.1",
     "reflect-metadata": "^0.1.13",
     "serialize-error": "^4.1.0",

packages/bus-core/src/bus-module.ts

@@ -2,7 +2,7 @@ import { ContainerModule, interfaces } from 'inversify'
 import { BUS_SYMBOLS, BUS_INTERNAL_SYMBOLS } from './bus-symbols'
 import { MessageAttributes } from '@node-ts/bus-messages'
 import { MemoryQueue } from './transport'
-import { ServiceBus, BusHooks } from './service-bus'
+import { ServiceBus, BusHooks, DefaultBusConfiguration } from './service-bus'
 import { JsonSerializer, MessageSerializer } from './serialization'
 import { ApplicationBootstrap } from './application-bootstrap'
 import { HandlerRegistry } from './handler'
@@ -31,6 +31,7 @@ export class BusModule extends ContainerModule {
       bindService(bind, BUS_INTERNAL_SYMBOLS.BusHooks, BusHooks).inSingletonScope()
 
       bind(BUS_SYMBOLS.MessageHandlingContext).toConstantValue(new MessageAttributes())
+      bind(BUS_SYMBOLS.BusConfiguration).toConstantValue(new DefaultBusConfiguration())
     })
   }
 }

packages/bus-core/src/bus-symbols.ts

@@ -6,10 +6,12 @@ export const BUS_SYMBOLS = {
   ApplicationBootstrap: Symbol.for('@node-ts/bus-core/application-bootstrap'),
   JsonSerializer: Symbol.for('@node-ts/bus-core/json-serializer'),
   MessageSerializer: Symbol.for('@node-ts/bus-core/message-serializer'),
-  MessageHandlingContext: Symbol.for('@node-ts/bus-core/message-handling-context')
+  MessageHandlingContext: Symbol.for('@node-ts/bus-core/message-handling-context'),
+  BusConfiguration: Symbol.for('@node-ts/bus-core/bus-configuration')
 }
 
 export const BUS_INTERNAL_SYMBOLS = {
   SessionScopeBinder: Symbol.for('@node-ts/bus-core/session-scope-binder'),
-  BusHooks: Symbol.for('@node-ts/bus-core/bus-hooks')
+  BusHooks: Symbol.for('@node-ts/bus-core/bus-hooks'),
+  RawMessage: Symbol.for('@node-ts/bus-core/raw-message')
 }

packages/bus-core/src/error/fail-message-outside-handling-context.ts

@@ -0,0 +1,20 @@
+import { Message } from '@node-ts/bus-messages'
+
+export class FailMessageOutsideHandlingContext extends Error {
+  /**
+   * Calling .fail() with a message indicates that the message received from the
+   * queue can not be processed even with retries and should immediately be sent
+   * to the dead letter queue.
+   *
+   * This error occurs when .fail() has been called outside of a message handling context,
+   * or more specifically - outside the stack of a Handler() operation
+   * @param msg The message that was attempted to be failed
+   */
+  constructor (
+    readonly msg: Message
+  ) {
+    super(`Attempted to fail message outside of a message handling context`)
+    // tslint:disable-next-line:no-unsafe-any
+    Object.setPrototypeOf(this, new.target.prototype)
+  }
+}

packages/bus-core/src/error/index.ts

@@ -0,0 +1 @@
+export * from './fail-message-outside-handling-context'

packages/bus-core/src/index.ts

@@ -1,8 +1,9 @@
 export { BUS_SYMBOLS } from './bus-symbols'
 export * from './bus-module'
-export * from './service-bus/bus'
+export * from './service-bus'
 export { Transport, TransportMessage } from './transport'
 export * from './application-bootstrap'
 export * from './handler'
 export * from './serialization'
 export * from './util'
+export * from './error'

packages/bus-core/src/serialization/json-serializer.ts

@@ -4,18 +4,22 @@ import { ClassConstructor } from '../util'
 import { classToPlain, plainToClass, serialize, deserialize } from 'class-transformer'
 
 /**
- * A very unsafe, basic JSON serializer. This will serialize objects to strings, but will
- * deserialize strings into plain objects. These will NOT contain methods or special types,
- * so the usage of this serializer is limited.
+ * A JSON-based serializer that uses `class-transformer` to transform to and from
+ * class instances of an object rather than just their plain types. As a result,
+ * object types can use all of the serialization decorator hints provided by
+ * that library.
  */
 @injectable()
 export class JsonSerializer implements Serializer {
-  serialize<T extends object> (obj: T): string {
+  serialize<ObjectType extends object> (obj: ObjectType): string {
     return serialize(obj)
   }
 
-  deserialize<T extends object> (val: string, classConstructor: ClassConstructor<T>): T {
-    return deserialize<T> (classConstructor, val)
+  deserialize<ObjectType extends object> (
+    serialized: string,
+    classConstructor: ClassConstructor<ObjectType>
+  ): ObjectType {
+    return deserialize<ObjectType> (classConstructor, serialized)
   }
 
   toPlain<T extends object> (obj: T): object {

packages/bus-core/src/serialization/message-serializer.spec.ts

@@ -1,10 +1,11 @@
 // tslint:disable:max-classes-per-file no-inferred-empty-object-type
 import { Serializer } from './serializer'
 import { ClassConstructor } from '../util'
-import { MessageSerializer } from './message-serializer';
+import { MessageSerializer } from './message-serializer'
 import { Mock, IMock, It } from 'typemoq'
 import { HandlerRegistry } from '../handler'
 import * as faker from 'faker'
+import { Message } from '@node-ts/bus-messages'
 
 class DummyMessage {
   $name = 'bluh'
@@ -18,12 +19,12 @@ class DummyMessage {
 
 class ToxicSerializer implements Serializer {
 
-  serialize (msg: any): string {
-    return msg.$name as string
+  serialize<ObjectType extends object> (obj: ObjectType): string {
+    return (obj as Message).$name
   }
 
-  deserialize<T extends object> (msg: string, classType: ClassConstructor<T>): T {
-    return new classType(msg)
+  deserialize<ObjectType extends object> (serialized: string, classType: ClassConstructor<ObjectType>): ObjectType {
+    return new classType(serialized)
   }
 }
 
@@ -49,27 +50,25 @@ describe('MessageSerializer', () => {
     )
   })
 
-  it ('should use underlying serializer to serialize', () => {
-    const msg = {
-      $name: msgName
+  it('should use underlying serializer to serialize', () => {
+    const message: Message = {
+      $name: msgName,
+      $version: 1
     }
-    const result = sut.serialize(msg)
-    // As per toxic serializer's behavior
-    expect(result).toBe(msg.$name)
+    const result = sut.serialize(message)
+    expect(result).toBe(message.$name)
   })
 
-  it ('should use underlying deserializer to deserialize', () => {
+  it('should use underlying deserializer to deserialize', () => {
     const msg = {
       $name: msgName,
       text: faker.random.words()
     }
     const raw = JSON.stringify(msg)
 
-    const result = sut.deserialize(raw) as DummyMessage
+    const result = sut.deserialize<DummyMessage>(raw)
 
     handlerRegistry.verifyAll()
-
-    // As per toxic serializer's behavior
     expect(result.value).toBe(raw)
   })
 })

packages/bus-core/src/serialization/message-serializer.ts

@@ -23,17 +23,18 @@ export class MessageSerializer {
   ) {
   }
 
-  serialize<T extends object> (obj: T): string {
-    return this.serializer.serialize(obj)
+  serialize<MessageType extends Message> (message: MessageType): string {
+    return this.serializer.serialize(message)
   }
 
-  deserialize (val: string): Message {
-      const naiveDerializedMessage = JSON.parse(val) as Message
+  deserialize<MessageType extends Message> (serializedMessage: string): MessageType {
+      const naiveDerializedMessage = JSON.parse(serializedMessage) as Message
       const messageType = this.handlerRegistry.getMessageType(naiveDerializedMessage)
 
-      return !!messageType ? this.serializer.deserialize(
-        val,
-        messageType
-      ) : naiveDerializedMessage
+      return (!!messageType
+        ? this.serializer.deserialize(
+          serializedMessage,
+          messageType
+        ) : naiveDerializedMessage) as MessageType
   }
 }

packages/bus-core/src/serialization/serializer.ts

@@ -1,6 +1,19 @@
 import { ClassConstructor } from '../util'
 
+/**
+ * A serializer that's use to serialize/deserialize objects as they leave and enter the application boundary.
+ */
 export interface Serializer {
-  serialize<T extends object> (obj: T): string
-  deserialize<T extends object> (val: string, classType: ClassConstructor<T>): T
+  /**
+   * Serializes a message into a string representation so it can be written to an underlying queue/topic
+   * @param obj Message to serialize
+   */
+  serialize<ObjectType extends object> (obj: ObjectType): string
+
+  /**
+   * Deserializes a string-based representation of an object back into a strong class type.
+   * @param serialized Serialized string of the object to deserialize
+   * @param classType Type of the class to deserialize the object back into
+   */
+  deserialize<ObjectType extends object> (serialized: string, classType: ClassConstructor<ObjectType>): ObjectType
 }

packages/bus-core/src/service-bus/bus-configuration.ts

@@ -0,0 +1,13 @@
+import { injectable } from 'inversify'
+
+export interface BusConfiguration {
+  /**
+   * The number of messages to handle in parallel
+   */
+  readonly concurrency: number
+}
+
+@injectable()
+export class DefaultBusConfiguration implements BusConfiguration {
+  readonly concurrency: number = 1
+}