Thallo & Hyperledger Fabric

Introduction

This project is an integration between

• thallo-starter-fabric-chaincode: spring-boot and fabric-chaincode-shim to create chaincode application.
• thallo-starter-fabric-gateway: spring-boot and fabric-gateway-java to build client (gateway) application.

Chaincode

Add following dependency to your Spring Boot's pom.xml file:

<dependency>
	<groupId>org.devocative.thallo</groupId>
	<artifactId>thallo-starter-fabric-chaincode</artifactId>
	<version>1.0</version>
</dependency>

You can create a contract like the following code:

@Default
@Contract(name = "sample")
@Component
public class SampleContract implements ContractInterface {
  @Transaction
  public String createAsset(final Context ctx, String name, BigDecimal price) {
    // Logics to create an Asset
    return id;
  }

  @Transaction(intent = EVALUATE)
  public byte[] getAsset(final Context ctx, String id) {
    final ChaincodeStub stub = ctx.getStub();
	  return stub.getState(id);
  }

	// Other functions ...
}

Now you can deploy your chaincode in hyperledger fabric network.

Gateway (client)

Add following dependency to your Spring Boot's pom.xml file:

<dependency>
	<groupId>org.devocative.thallo</groupId>
	<artifactId>thallo-starter-fabric-gateway</artifactId>
	<version>1.0</version>
</dependency>

Then annotate your spring main class with @EnableFabricGateway:

@EnableFabricGateway
@SpringBootApplication
public class SampleGatewayApplication {
  public static void main(String[] args) {
    SpringApplication.run(SampleGatewayApplication.class, args);
  }
}

Finally, create an interface such as the following one:

@FabricClient
public interface ISampleContract {

  @Submit
  String createAsset(String name, BigDecimal price);

  @Evaluate
  Asset getAsset(String id);

  @Evaluate(method = "getAsset")
  byte[] getAssetArr(String id);

  @Evaluate(method = "getAsset")
  String getAssetStr(String id);

  // map other functions here
}

As you can see, this module is like OpenFeign, and you can represent the contract class just with an interface. The thallo-starter-fabric-gateway module implements the interface at runtime, and call all the necessary code to send your request to fabric network.

Note that the following config in your application.yml is necessary for the above code:

thallo:
  fabric:
    gateway:
      chaincode: # Chaincode Name
      channel: # Channel Name
      connection-profile-file: # File address to an ORG's connection profile 
      org-msp-id: # The ORG's MSP Id
      ca:
        wallet-dir: # A directory where the Fabric CA's client wallet is created
        server:
          pem-file: # File address to Fabric CA's root certificate in pem format 
          url: # ORG's Fabric CA's URL
          username: # Already created username in ORG's Fabric CA
          password: # The password for the above username

Start Fabric Services in Dev Mode

• Clone this repository
• Download configtxgen, orderer, and peer binary files from Fabric's GitHub
  • Create dir start-fabric-dev-mode/files/bin and copy mentioned files in it
• Exec ./start-fabric-dev-mode/run.sh start
• Now start your chaincode spring boot application with following configuration (application.yml):

thallo:
  fabric:
    chaincode:
      id: "mycc:1.0"
      dev-mode:
        enabled: true
      server-address: "127.0.0.1:9999"