Fabric Composer

Overview

Fabric Composer is a set of APIs, a modeling language and a programming model to quickly define and deploy business networks and applications that allow participants to send transactions that exchange assets.

The IBM Blockchain, based on Open Source Hyperledger Fabric technology, is used to store the state of assets in asset registries, while the blockchain consensus protocol ensure that transactions are validated by concerned organizations in the business network.

Framework Features

Fabric Composer Programming Model

The Fabric Composer programming model is based on defining and deploying a Business Network Definition, which contains a data model that defines the name and structure of assets, participants and transactions in the business network. The business network also specifies transaction processor functions (written in ES5 Javascript) that are automatically run on a Hyperledger Fabric when transactions are submitted by clients.

Fabric Composer defines Javascript APIsto submit transactions and to create, retrieve, update and delete assets within asset registries.

Roles, Responsibilities and Tasks

A typical project using Fabric Composer goes through a lifecycle of:

Model -> Define Business Network -> Deploy Runtime -> Deploying Business Network -> Test -> Generate Application

These tasks may all be performed by a single full-stack developer, but are more typically performed by: * Business analyst, responsible for defining the data model * Technical analyst, responsible for creating the business network definition, including models and writing transaction processor functions, as well as dashboards and analytics to business stakeholders * Operations engineer, responsible for operating a set of Hyperledger nodes, ensuring business continuity and security * Application developer, responsible for creating web and batch applications and integrating the applications into existing systems

Modeling the Business Domain

Fabric Composer includes a powerful Object-Oriented modeling language, used to specify a domain model; the structure of assets, participants and transactions. The domain model is used across the Framework for code generation, type validation, user interface generation, API generation, amongst other things.

Sample Fabric Composer Domain Model

namespace net.biz.digitalPropertyNetwork

asset LandTitle identified by titleId {
  o String   titleId
  o Person   owner
  o String   information
  o Boolean  forSale   optional
}

asset SalesAgreement identified by salesId {
  o String    salesId
  o Person    buyer
  o Person    seller
  o LandTitle title
}

participant Person identified by personId {
  o String personId
  o String firstName
  o String lastName
}


transaction RegisterPropertyForSale identified by transactionId{
  o String transactionId
  --> Person seller
  --> LandTitle title
}

Writing Transaction Processor functions

Technical Analysts write transaction processor functions using ES5 Javascript. These scripts are included in a business network definition and will be automatically executed when a transaction is submitted for processing. The transaction processor scripts can create, update, retrieve and delete assets based on the incoming transaction.

'use strict';

/** Process a property that is held for sale
 * @param {net.biz.digitalPropertyNetwork.LandTitle} propertyForSale the property to be sold
 * @transaction
 */
function onRegisterPropertyForSale(propertyForSale){
    console.log('### onRegisterPropertyForSale '+propertyForSale.toString());
    propertyForSale.title.forSale = true;
}

Rapidly Create Applications

Fabric Composer includes code generators so that web and mid-tier application developers can quickly generate starter applications that interact with a deployed business network definition. These code generators allow application developers to quickly focus on the integration and visual aspects of their projects, rather than writing boilerplate and configuration.

High-level administration and client APIs provide easy access to a deployed business network.

Using the Javascript Client and Admin APIs

Mid-tier developers use Javascript APIs to interact with the framework. The AdminConnection API exposes administration operations, such as deploying, undeploying and updating a Business Network Definition.

The BusinessNetworkConnection API is used to interact with a deployed business network: retrieving assets from asset registries, or submitting transactions.

The sample below uses both the AdminConnection and BusinessNetworkConnection APIs to deploy a business network definition, and then connects using the client API to retrieve an asset registry.

'use strict';

const AdminConnection = require('composer-admin').AdminConnection;
const BusinessNetworkConnection = require('composer-client').BusinessNetworkConnection;
const BusinessNetworkDefinition = require('composer-common').BusinessNetworkDefinition;
const fs = require('fs');

const admin = new AdminConnection();
const concerto = new BusinessNetworkConnection();

const config = {
    type: 'hlf',
    keyValStore: '/tmp/keyValStore',
    membershipServicesURL: 'grpc://localhost:7054',
    peerURL: 'grpc://localhost:7051',
    eventHubURL: 'grpc://localhost:7053'
};

const CONNECTION_PROFILE_NAME = 'testprofile';
let businessNetworkIdentifier = null;

return admin.createProfile('testprofile', config)
  .then(() => {
      console.log('Created connection profile');
      return admin.connect(CONNECTION_PROFILE_NAME, 'WebAppAdmin', 'DJY27pEnl16d');
  })
  .then(() => {
      let readFile = fs.readFileSync(__dirname + '/data/businessnetwork.zip');
      return BusinessNetworkDefinition.fromArchive(readFile);
  })
  .then((businessNetwork) => {
      console.log('Read BusinessNetwork archive: ' + businessNetwork.getIdentifier() );
      businessNetworkIdentifier = businessNetwork.getIdentifier();

      console.log('Deploying business network...' );
      return admin.deploy(businessNetwork, false);
  })
  .then(() => {
      console.log('Deployed BusinessNetwork archive');
      return admin.ping();
  })
  .then(() => {
      console.log('Pinged server');
      return admin.disconnect();
  })
  .then(() => {
      console.log('Disconnected admin');
      return concerto.connect(CONNECTION_PROFILE_NAME, businessNetworkIdentifier, 'WebAppAdmin', 'DJY27pEnl16d');
  })
  .then(() => {
      console.log('Connected client to ' + businessNetworkIdentifier );
      return concerto.addAssetRegistry('com.ibm.concerto.mozart.Farmer', 'Farmer Registry');
  })
  .then((registry) => {
      console.log('Found animal asset registry ' + registry );
  })
  .then(() => {
      return concerto.disconnect();
  })
  .then(() => {
      console.log('Done');
      return true;
  })
  .catch((err) => {
      console.log('Failed: ' + err);
  });

Developing Web User Interfaces

Front-end developers use domain-specific (dynamically generated from the domain model for the business network definition) to interact with assets and asset registries.

In addition, if they are building an Angular2 application, they may generate Typescript types from the domain model, ensuring type-safety in the user interface code they are writing.