Composer-Runtime

npm install composer-runtime --save

Introduction

This repository contains the core runtime code for Fabric Composer. The runtime code is deployed to the Blockchain, and provides the support for managing business networks, registries and resources, and execution of transaction processor functions.

The runtime code is designed so that it can be executed on both a real Blockchain implementation (Hyperledger Fabric) and also standalone in a web browser for rapid development and testing purposes. To ensure that this is possible, the code in this repository must be kept isolated from the underlying Blockchain technology.

Runtime Components

The Fabric Composer runtime is split into several components to allow the runtime code to execute in multiple environments. Those components are as follows:

Container

The runtime code in this repository is hosted in a Container. The Container is responsible for starting the Engine, routing calls from the client and administrative APIs into the Engine, and exposing the Blockchain to the Engine via a set of Services.

Two Container implementations currently exist:

• Hyperledger Fabric (Go): Composer-Runtime-Hyperledger-Fabric
• Web/in-browser (JavaScript): Composer-Runtime-Web

The Container interface is defined in lib/container.js.

Engine

The Engine provides all of the core code for managing business networks, registries and resources, and execution of transaction processor functions. Calls from the client and administrative APIs are handled by the generic Engine.init, Engine.invoke, or Engine.query functions in lib/engine.js which then forward the call onto the specific handler functions.

The specific handler functions are organised into separate files:

• Business Network management: lib/engine.businessnetworks.js
• Registry management: lib/engine.registries.js
• Resource management: lib/engine.resources.js
• Transaction execution: lib/engine.transactions.js

The Container will start a single instance of the Engine and make multiple calls to it. The Engine code must also support multiple in-flight requests, and this is made possible by the Context which is passed into the Engine by the Container.

Services

A set of Services are provided by the Container for use by the Engine. The current set of Services that must be provided by the Container are:

• The logging service, for writing log entries: lib/loggingservice.js
• The data service, for interacting with the world state: lib/dataservice.js

There are two different types of Services:

• Container level services, available from the Container interface.
• Context level services, available from the Context interface.

The Container level services are not linked to the request, such as the logging service. The Context level services are linked to the request, such as the data service.

License

Hyperledger Project source code files are made available under the Apache License, Version 2.0 (Apache-2.0), located in the LICENSE file. Hyperledger Project documentation files are made available under the Creative Commons Attribution 4.0 International License (CC-BY-4.0), available at http://creativecommons.org/licenses/by/4.0/.