Hyperledger Burrow is one of the Hyperledger projects hosted by The Linux Foundation. Hyperledger Burrow provides a modular blockchain client with a permissioned smart contract interpreter partially developed to the specification of the Ethereum Virtual Machine (EVM). Hyperledger Burrow is a permissioned blockchain node that executes smart contract code following the Ethereum specification. Burrow is built for a multi-chain universe with application specific optimization in mind. Burrow as a node is constructed out of three main components: the consensus engine, the permissioned Ethereum virtual machine and the rpc gateway. Here we’ll explain how to create a pet shop dapp using Hyperledger Burrow blockchain.
Pet shop dapp using Hyperledger Burrow blockchain
This is an example project that is running EVM. A Solidity contract has been written for Hyperledger Burrow. Then run the Ethereum Petshop dapp on Hyplerger Burrow. Follow the below documentation.
Note: a Nodejs package named snak is utilized to interact with Hyperledger Burrow. Make sure to run all snak commands in the Petshop-HyperledgerBurrow’ Directory.
Requirements to run Hyperledger Burrow
- Git
- Nodejs
Installations
To install git
$ sudo apt install git>
then to install Nodejs
$ sudo apt install curl
$ curl -sL https://deb.nodesource.com/setup_8.x | sudo bash -
$ sudo apt install nodejs
Now that you have Git , nodejs and npm install. We need to clone the pet shop Hyperledger Burrow directory to the local machine.
$ git clone https://github.com/DevProvider/PetShop-HyperledgerBurrow.git
$ cd PetShop-HyperledgerBurrow
We can install snak now.
$ npm install -g snak
If you get errors or warnings during installing Snak. try
$ sudo npm install --unsafe-perm --verbose -g snak
after snak is installed.
Now lets start setting up the blockchain.
Setup
Open terminal in your Petshop-HyperledgerBurrow Directory and type.
./monax-keys server
Let this running in a terminal.
open another terminal and import all the accounts keys to monax server.
go to Petshop-HyperledgerBurrow Directory and type
$ snak import_kets account_list.json
After the keys are imported. You can now run Hyperledger burrow.
$ snak run_burrow
Compiling and deploying Smart contracts
In the same directory, type
$ snak compile
To compile the adoption contract written in Solidity,
Now make sure that Burrow is running in another terminal and migrate the smart contracts to burrow.
$ snak migrate
The blockchain will give you the address of your smart contract and that means that its up and running.
If you want to test your smart contract. You can do it by calling the smart contract functions.
There is a method in our smart contracts that gets the address of all the adopters on the blockchain. The method name is getAdopters.
$ snak call Adoption getAdopters
This is a default call that will give you all the address in the blockchain.
Handle a common error
If by any chance when you call $ snak call Adoption getAdopters and it return with an error saying TypeError: cannot read the propoerty ‘toUpperCase’ of undefined.
then open a new terminal.
go to the file dev_pipe that your error is showing you.
My file lies in
$ cd user/lib/node_modules/snak/node_modules/burrow-contracts/lib/pipes/
One in this directory . Open the file dev_pipes.js
$ gedit dev_pipes.js
Go to the line 124 and change the data.return.toUpperCase() to data.Return.toUpperCase()
Just change the R to capital and it will fix the error. type
$ snak call Adoption getAdopters
and you should get the Adopters.
Running the blockchain with fronend GUI
Assuming you have done all the above steps. To run the application and interact with the blockchain using your front-end pet shop application. Follow the steps.
- Go to the Petshop-Hyperledger burrow directory
- Open terminal and type
$ snak run_burrow - Open another teminal and type
$ npm start
Go to http://localhost:3000
Enjoy the application.
Empty the Burrow blockchain
In order to empty the blockchain you have to compile and migrate your smart contract again to the blockchain.
$ snak compile
$ snak migrate
Interacting with Burrow Blockchain using Snak
You can interact with your Hyperledger Burrow blockchain using snak by using the following commands.
-V, --version otput the version number
-h, --help output usage information
Commands:
init|int
Initialize project, makes folders and files which are needed for starting a dapp project.
compile|cmp
Compile all contracts in contracts folder and makes artifacts in the build folder
you need to initialize a project before using this command.
migrate|mgt [accountname]
deploy contract on the Burrow
you need to initialize a project before using this command.
list_accounts|acnt
Load all accounts
you need to initialize a project before using this command.
default_accounts|acnt
List all predefined accounts
No need to initialize a project before using this command.
create_account|crtac <pass_phrase>
Creates unsafe account included private key, public key and address and displays on the terminal,
No need to initialize a project before using this command.
balance|blnc <address>
Get balance of a specefic account
No need to initialize a project before using this command.
transact|tx <priv_key> <data> <address> <fee> <gas_limit>
Do regular transaction to a contract, you need pass the private key of sender and address of contract
you need to initialize a project before using this command.
send|snd <priv_key> <address> <fee>
Do regular transaction, you need pass the private key of sender and address of reciever
you need to initialize a project before using this command.
random_transact|rtx <count>
Doing random Transaction,
you need to initialize a project before using this command
you should put a list of accounts(name = account_list.json) in accounts folder first!.
install_burrow|insl
install burrow blockchain, and copy the files to the home directory (.burrow),
No need to initialize project for this command.
uninstall_burrow|unsl
uninstall burrow blockchain, and back up the files to the home directory (burrow-backup),
No need to initialize project for this command.
run_burrow|rnbrw
run burrow blockchain,you need install burrow first!,
No need to initialize project for this command.
*
call|calf <contract_name> <function_name> <parameters_list>
Calls the function of specefic contract, you need to pass the list of parameters like this var1,var2,...,varK ,comma separated.
You need to initialize a project before using this command.
run_monax_keys|rks [ip_address]
Runs the Monax key server on port 4776,
No need to initialize a project before using this command.
import_keys|imks <file_name>
Import keys in the monax key server
No need to initialize a project before using this command.
chain_id|chid
Get chain id of the blockchain
You need to initialize a project before using this command.
genesis_hash|genhash
Get Genesis Hash of the blockchain
You need to initialize a project before using this command.
latest_block_height|lbckh
Get Latest Block Hash of the blockchain
You need to initialize a project before using this command.
info|inf
Get Info of the blockchain
You need to initialize a project before using this command.
latest_block|lbck
Get Latest Block of the blockchain
You need to initialize a project before using this command.
config|conf
Get the current config of the snak
If you haven't created any project burrow url will be http://127.0.0.1:1337/rpc by default
You may need to initialize a project before using this command.This was a simple example of how to run the Ethereum Pet shop dapp on Hyperledger Burrow using the Snak tool.
If you want to design a dapp using Hyperledger Burrow for yourself or your business. Don’t hesitate to contact our blockchain development company. Free consultations available.