project3

Ethereum Dapp for Tracking Items through Supply Chain

Submission Information

• UML Diagrams
• Libraries Write-up
• IPFS Write-up
• General Write-up

Summary

The purpose of this project is to learn lower level components of establishing a sound web service architecture using Blockchain. In this project, I created a dApp coffee supply chain solution on Ethereum using smart contracts with role-based permissions to track and verify a product's authenticity. The code for this project is in the coffee/ folder.

Testing The dApp

Below is the output from my tests in the test folder. To run the tests, simply execute truffle test at the command line.

Contract Owner: accounts[0]  0x27d8d15cbc94527cadf5ec14b69519ae23288b95
Farmer: accounts[1]  0x018c2dabef4904ecbd7118350a0c54dbeae3549a
Distributor: accounts[2]  0xce5144391b4ab80668965f2cc4f2cc102380ef0a
Retailer: accounts[3]  0x460c31107dd048e34971e57da2f99f659add4f02
Consumer: accounts[4]  0xd37b7b8c62be2fdde8daa9816483aebdbd356088


  Contract: SupplyChain
    ✓ Test that roles are correctly added to contract (184ms)
    ✓ Testing smart contract function harvestItem() that allows a farmer to harvest coffee (108ms)
    ✓ Testing smart contract function processItem() that allows a farmer to process coffee (58ms)
    ✓ Testing smart contract function packItem() that allows a farmer to pack coffee (58ms)
    ✓ Testing smart contract function sellItem() that allows a farmer to sell coffee (55ms)
    ✓ Testing smart contract function buyItem() that allows a distributor to buy coffee (67ms)
    ✓ Testing smart contract function shipItem() that allows a distributor to ship coffee (66ms)
    ✓ Testing smart contract function receiveItem() that allows a retailer to mark coffee received (65ms)
    ✓ Testing smart contract function purchaseItem() that allows a consumer to purchase coffee (52ms)
    ✓ Testing smart contract function fetchItemBufferOne() that allows anyone to fetch item details from blockchain
    ✓ Testing smart contract function fetchItemBufferTwo() that allows anyone to fetch item details from blockchain


  11 passing (821ms)

Running the dApp

Screenshots etc

UML Diagrams

As part of the project planning, I created UML activity, sequence, and state diagrams which are included below.

Activity Diagram

Sequence Diagram

State Diagram

Classes (Data Model)

Libraries Write-up

Below are the dependencies in my packages.json file:

"dependencies": {
    "solidity-docgen": "^0.5.7",
    "truffle": "^5.1.51",
    "truffle-assertions": "^0.9.2",
    "truffle-hdwallet-provider": "^1.0.17",
    "web3": "^1.3.0"
  }

Why I used each library:

• solidity-docgen: I tried out using solidity docgen to generate documentation for my smart contracts. The generated documentation is in a gitbook contained in the docgen folder. This library might be useful for future projects as smart contract libraries can get quite complex.
• truffle: truffle is a development framework for Ethereum that makes it easy to compile, test, and migrate solidity contracts to Ethereum networks. For example, I used truffle to deploy my smart contracts to the Rinkeby test network.
• truffle-assertions: the assertions library for truffle has convenience functions designed for solidity assertions inside of truffle tests. I used the assertion syntax to test whether my contracts correctly emitted different events as expected.
• truffle-hdwallet-provider: this libarary was used to enable my truffle deployments to spend test coins from my Metamask wallet on the Rinkeby network as part of deploying my contracts to Rinkeby
• web3:

IPFS Write-up

I did not use IPFS for this project.

General Write-up

I built the dApp in five parts:

• Part 1 - Plan the project: I made UML diagrams and described the libraries that I chose to use and why I chose to use them
• Part 2 - Write smart contracts: Based on the drafted specifications, I defined the required interfaces for the smart contracts and added the specific logic to each of the contracts: (i) AccessControl (ii) Base (iii) Core
• Part 3 - Test smart contract code coverage: I drafted tests to cover every function in the sequence diagram from Part 1 and ensured that all tests were passing.
• Part 4 - Deploy smart contracts on Rinkeby: I used the Truffle framework and Infura to deploy my smart contracts onto the Rinkeby test network.
• Part 5 - Build the frontend: I created a frontend interface that allows users to interact with the smart contracts from the web.

The Rinkeby contract address for this project is: 0xa2033443417Dd94D7dc2BEffeaD213F270558D1E

Smart contract documentation can be generated using solidity-docgen.