rkly / blockchainevents-compositejourney

Part 3 in a series of patterns showing the building blocks of a Blockchain application

Hyperledger Composer - Product Auction Network With Events

Read this in other languages: 한국어,**

Welcome to Part 3 of the Hyperledger Composer Composite Pattern. This is a continuation of Hyperledger Composer - Product Auction Network. This pattern shows how events can be emitted by Hyperledger Composer and subscribed by external applications.

Audience level : Intermediate Developers

If you have an IBM Cloud Lite account, you can also use the Starter Plan for 30 days to do this pattern.

Included Components

• Hyperledger Fabric
• Hyperledger Composer
• Docker

Application Workflow Diagram

• Start the Hyperledger Fabric Network
• Generate and Deploy the Business Network Archive
• Start and connect the composer rest server to deployed business network
• Start the Web Application

Steps

1. Generate the Business Network Archive (BNA)
2. Deploy the Business Network Archive to Local Hyperledger Fabric instance
3. Start the Web UI
4. Submit Transactions

1. Generate the Business Network Archive (BNA)

Make sure that you have installed the prerequisites for Hyperledger Composer. Also, make sure that you have installed the development environment which includes Hyperledger Composer, Hyperledger Fabric and the other node modules using these instructions. As a recap for those instructions, you should have done the following:

• Installed Hyperledger Composer and it's related Node modules using npm.
• Downloaded the docker images for Hyperledger Fabric.
• Started Hyperledger Fabric locally on your machine.
• Executed createPeerAdminCard.sh to create a network card that will be used to install the business network later in this exercise.

Clone the repository:

$ git clone https://github.com/IBM/BlockchainEvents-CompositeJourney.git

To check that the structure of the files is valid, you can now generate a Business Network Archive (BNA) file for your business network definition. The .bna file is the deployable unit -- a file that can be deployed to the Hyperledger Composer runtime for execution.

Use the following command to generate the network archive:

$ cd BlockchainEvents-CompositeJourney/Composer
$ npm install

You should see the following output:

$ mkdirp ./dist && composer archive create --sourceType dir --sourceName . -a ./dist/events.bna

Creating Business Network Archive


Looking for package.json of Business Network Definition
	Input directory: /Users/ishan/Documents/demo/BlockchainEvents-CompositeJourney/Composer

Found:
	Description: Sample product auction network with events
	Name: events
	Identifier: [email protected]

Written Business Network Definition Archive file to
	Output file: ./dist/events.bna

Command succeeded

The composer archive create command has created a file called events.bna in the dist folder.

You can test the business network definition against the embedded runtime that stores the state of 'the blockchain' in-memory in a Node.js process. From your project working directory, open the file test/productAuction.js and run the following command:

$ npm test

You should see the following output :

> [email protected] test /Users/ishan/Documents/demo/BlockchainEvents-CompositeJourney/Composer
> nyc mocha -t 0 test/*.js



  #org.acme.product.auction
    ✓ Authorized owner should start the bidding (74ms)
    ✓ Members bid for the product (139ms)
    ✓ Close bid for the product (175ms)


  3 passing (2s)

----------|----------|----------|----------|----------|-------------------|
File      |  % Stmts | % Branch |  % Funcs |  % Lines | Uncovered Line #s |
----------|----------|----------|----------|----------|-------------------|
All files |        0 |        0 |        0 |        0 |                   |
----------|----------|----------|----------|----------|-------------------|

2. Deploy the Business Network Archive to Local Hyperledger Fabric instance

Make sure that you have started Hyperledger Fabric instance locally on your machine using these instructions. Now change directory to the dist folder containing events.bna file and execute the following commands to install/deploy and start the business network on the local Hyperledger Fabric instance:

$ cd BlockchainEvents-CompositeJourney/Composer/dist
$ composer network install -c PeerAdmin@hlfv1 -a events.bna
$ composer network start -c PeerAdmin@hlfv1 -n events -V 0.0.1 -A admin -S adminpw -f networkadmin.card
$ composer card import --file networkadmin.card

You can verify that the network has been deployed by typing:

$ composer network ping --card admin@events

You should see the the output as follows:

The connection to the network was successfully tested: events
The connection to the network was successfully tested: events
	Business network version: 0.0.1
	Composer runtime version: 0.19.5
	participant: org.hyperledger.composer.system.NetworkAdmin#admin
	identity:org.hyperledger.composer.system.Identity#e7eaa3bc255f5ded89fd5c25748aca87959c9b3fc6ad6a94c65d679162db84fd
Command succeeded

To create the REST API we need to launch the composer-rest-server and tell it how to connect to our deployed business network. Now launch the server by changing directory to the product-auction folder and type:

$ cd BlockchainEvents-CompositeJourney/Composer
$ composer-rest-server

? Enter the name of the business network card to use: admin@events
? Specify if you want namespaces in the generated REST API: never use namespaces
? Specify if you want to use an API key to secure the REST API: No
? Specify if you want to enable authentication for the REST API using Passport: No
? Specify if you want to enable event publication over WebSockets: Yes
? Specify if you want to enable TLS security for the REST API: No

Test REST API

If the composer-rest-server started successfully you should see these two lines are output:

Web server listening at: http://localhost:3000
Browse your REST API at http://localhost:3000/explorer

3. Start the Web UI

In a new terminal window, navigate to Web directory and launch the node server using command:

cd BlockchainEvents-CompositeJourney/Web
$ npm install
$ node server.js

4. Submit Transactions

Submit transactions for auction network using the instructions in Hyperledger Composer Section. Events are emitted when user submits publishListing, makeoffer and closeBidding transactions. Web UI for seller and buyer updates on the event emitted from the Hyperledger Fabric network.

You can submit the transactions either by using Hyperledger Composer REST API or Hyperledger Composer Playground running locally.

Using REST API

Open a web browser and navigate to http://localhost:3000/explorer.

Using Composer Playground

You can Install the Hyperledger Composer Playground locally as shown below:

$ npm install -g composer-playground

And, run the Hyperledger Composer Playground locally using:

$ composer-playground

Navigate to http://localhost:8000/seller.html and http://localhost:8000/buyer.html to view the dashboards for Seller and Buyer events.

Additional Resources

• Hyperledger Fabric Docs
• Hyperledger Composer Docs

License

Apache 2.0