How to Deploy and Expose Chaincode as a REST API on Amazon Managed Blockchain Hyperledger Fabric 1.2

How to Deploy and Expose Chaincode as a REST API on Amazon Managed Blockchain Hyperledger Fabric 1.2

Blockchain technology is transforming every industry, and one of the most prominent players in this space is Hyperledger Fabric. In this guide, we will walk you through the process of deploying and exposing chaincode as a REST API on Amazon Managed Blockchain Hyperledger Fabric 1.2.

What is Hyperledger Fabric?

Hyperledger Fabric is a blockchain framework implementation that allows components, such as consensus and membership services, to be plug-and-play. It leverages container technology to host smart contracts called “chaincode” that comprise the application logic of the system.

Step 1: Setting Up Your Environment

Firstly, you need to set up your environment. Ensure you have installed the AWS CLI and configured it with your credentials. You also need the latest Docker versions, Node.js, npm, and the Hyperledger Fabric SDK for Node.js.

npm install fabric-ca-client fabric-client

Step 2: Setting up Hyperledger Fabric on Amazon Managed Blockchain

Launch your Hyperledger Fabric network using the Amazon Managed Blockchain service. Once your network is up and running, you will have access to your membership details, peer nodes, and ordering service.

Step 3: Writing Your Chaincode

Now, you need to write your chaincode. Chaincode is a piece of code written in one of the supported languages, such as Go, Node.js, or Java, that implements your blockchain’s business logic.

// A simple Chaincode example
const shim = require('fabric-shim');

const Chaincode = class {
  async Init(stub) {
    return shim.success();
  }

  async Invoke(stub) {
    let ret = stub.getFunctionAndParameters();
    console.info(ret);

    let method = this[ret.fcn];
    if (!method) {
      console.error('No function of name:' + ret.fcn + ' found');
      return shim.error('Received unknown function invocation');
    }

    try {
      let payload = await method(stub, ret.params, this);
      return shim.success(payload);
    } catch (err) {
      console.error(err);
      return shim.error(err);
    }
  }
};

shim.start(new Chaincode());

Step 4: Deploying Your Chaincode

After writing your chaincode, you need to package it and install it on your peers.

peer chaincode install -n mycc -v 1.0 -p github.com/hyperledger/fabric/examples/chaincode/go/chaincode_example02

Then, you need to instantiate your chaincode on the channel.

peer chaincode instantiate -o $ORDERER -C mychannel -n mycc -v 1.0 -c '{"Args":["init","a","100","b","200"]}' -P "OR ('Org1MSP.member','Org2MSP.member')"

Step 5: Exposing Your Chaincode as a REST API

The final step is to expose your chaincode as a REST API. For this, we will use the Hyperledger Fabric SDK for Node.js.

First, you need to set up the connection profile for your network, and then write the API that interacts with your chaincode.

app.get('/api/query', async (req, res) => {
  let network = await gateway.getNetwork('mychannel');
  let contract = network.getContract('mycc');

  let result = await contract.evaluateTransaction('query', 'a');
  res.status(200).json({response: result.toString()});
});

Now, your chaincode is exposed as a REST API and can be interacted with using HTTP requests.

Conclusion

Deploying and exposing chaincode as a REST API on Amazon Managed Blockchain Hyperledger Fabric 1.2 has a variety of applications. It allows developers to interact with the blockchain in a familiar way, making it easier to integrate blockchain technology into existing systems. We hope this guide has helped you understand the process better. Happy coding!

Keywords:

Hyperledger Fabric, Chaincode, Amazon Managed Blockchain, REST API, Blockchain Technology, AWS CLI, Docker, Node.js, npm, Hyperledger Fabric SDK, Smart Contracts, Business Logic, Blockchain Framework.

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