Intro to Private Blockchains

Launch the Sample App

If you haven’t gone through the environment setup steps, please visit the previous section.

Because Hyperledger networks require multiple nodes operating with different roles, we’ll need to simulate not just a single node, but a whole network. In this case, we’ll use the docker containers provided by the Hyperledger consortium to set up a testing network. Docker allows us to run several virtual machines, each with a chosen purpose, and will help to simulate a wider network.

INSTALLATION PROCEDURE

Before we start, you’ll want to make sure the first network example is down. Be sure to run this command from the first-network directory.

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shut down the network and clear docker

alex@ubuntu: ~/fabric-samples/ $ ./byfn.sh down // shut down the network
alex@ubuntu: ~/fabric-samples/ $ cd ../fabcar/ // Switch to the example directory
alex@ubuntu: ~/fabric-samples/ $ docker rm -f $(docker ps -aq // clean up docker files
alex@ubuntu: ~/fabric-samples/ $ docker network prune
alex@ubuntu: ~/fabric-samples/ $ docker rmi dev-peer0.org1.example.com-fabcar-1.0-5c906e402ed29f20260ae42283216aa75549c571e2e380f3615826365d8269ba

This quickly clears the old image and prunes the network. This step is important when testing multiple docker apps to avoid any overlap or interference. (More on this here.)

Now that we have everything set up on the Hyperledger end, we can install our node.js client.

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Install the Node Modules

alex@ubuntu: ~/fabric-samples/fabcar/ $ npm install

Now that everything is cleaned up, we’re ready to start experimenting!