BlockChain on Docker
What is a BlockChain?
Blockchain is a distributed database that maintains a continuously-growing list of ordered records called blocks. This technology underlying Bitcoin and other cryptocurrencies.
It is a public ledger of all Bitcoin transaction. These blocks are added in a chronological order.
In order to deploy a Blockchain applicatiIn order to deploy a Blockchain application, you need a distributed Hyperledger Blockchain on your choice of infrastructure (on-premise or cloud).
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In this article we will deploy a Hyperledger Fabric cluster using Docker.
Prerequisites
To follow this guide you need a system with working Docker engine and docker-compose on it. We will use Fabric which is an implementation of Blockchain technology written in Golang, so go version go1.6.2 or above is required. Before proceeding further let’s have a look on Hyperledger Fabric.
The HyperLedger Project
Hyperledger is an open source project with collaborative effort created to advance Blockchain technology.
It helps in cross-industry distributed ledgers which support transaction system, property transaction, and other services.
HyperLedger Fabric
Fabric is an implementation of blockchain technology. It provides a modular architecture allowing pluggable implementations of the various function.
Setting HyperLedger Cluster
Pulling Images
First, pull the latest images published by the Hyperledger fabric project from DockerHub.
docker pull hyperledger/fabric-peer:latest
docker pull hyperledger/fabric-membersrvc:latest
Now in order to run these images. Create a docker-compose file which will launch both of these services.
membersrvc:
image: hyperledger/fabric-membersrvc
ports:
- "7054:7054"
command: membersrvc
vp0:
image: hyperledger/fabric-peer
ports:
- "7050:7050"
- "7051:7051"
- "7053:7053"
environment:
- CORE_PEER_ADDRESSAUTODETECT=true
- CORE_VM_ENDPOINT=unix:///var/run/docker.sock
- CORE_LOGGING_LEVEL=DEBUG
- CORE_PEER_ID=vp0
- CORE_PEER_PKI_ECA_PADDR=membersrvc:7054
- CORE_PEER_PKI_TCA_PADDR=membersrvc:7054
- CORE_PEER_PKI_TLSCA_PADDR=membersrvc:7054
- CORE_SECURITY_ENABLED=false
- CORE_SECURITY_ENROLLID=test_vp0
- CORE_SECURITY_ENROLLSECRET=MwYpmSRjupbT
links:
- membersrvc
command: sh -c "sleep 5; peer node start --peer-chaincodedev"
That’s it now we are ready to launch these service by simply running docker-compose up
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Running the ChainCode
Before running chaincode you need to set your $GOPATH and then make a directory to download the sample chaincode in the src directory.
mkdir -p $GOPATH/src/github.com/chaincode_example02/
cd $GOPATH/src/github.com/chaincode_example02
Curl --request GET https://raw.githubusercontent.com/hyperledger/fabric/master/examples/chaincode/go/chaincode_example02/chaincode_example02.go > chaincode_example02.go
Next, you’ll need to download the Hyperledger fabric to your local $GOPATH, after that you have to build the chaincode.
mkdir -p $GOPATH/src/github.com/hyperledger
cd $GOPATH/src/github.com/hyperledger
git clone http://gerrit.hyperledger.org/r/fabric
Go to chaincode_example02 directory and build the code
cd $GOPATH/src/github.com/chaincode_example02
go build
Starting And Registering The ChainCode
Run the following command to start the chaincode.
CORE_CHAINCODE_ID_NAME=mycc CORE_PEER_ADDRESS=0.0.0.0:7051 ./chaincode_example02
After that chaincode console will display the message “Received REGISTERED, ready for invocations” which shows that chaincode is ready for use.
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Running Rest API
To log in with the help of REST API, send a POST request to the /registrar endpoint, with the enrollment ID and enrollment PW. These parameters are listed in the eca.users section of the membersrvc.yaml file.
REST Request:
POST localhost:7050/registrar
{
"enrollId": "jim",
"enrollSecret": "6avZQLwcUe9b"
}
REST Response:
200 OK
{
"OK": "Login successful for user 'jim'."
}
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