Containerized Ethereum Network

Automated containerized Ethereum (geth) Network using shell scripting, with sample python script to execute a smart contract.

Note that Blockchain & crypto currency are nascent technologies and can change at anytime.

So this setup might stop working in future.

There are many great guides and articles out there. This is a implementation which can be easily understood by any programer

This setup was tested on Windows & Ubuntu.

Prerequisite

1. docker or docker-toolbox (windows) should be installed.

2. Install python 3.6

3. Install build tools for visual studio 2017 from one of the link. It is 4+ gb download and takes 20-30min installation time.

   click here to know the reason

4. Install git

5. On Windows install git bash or cygwin. Linux users can skip this step.

6. Clone my repository : git clone https://github.com/Mastro-Geppetto/containerizedEthereumNetwork.git

7. Update python setuptools : pip install --upgrade setuptools

8. Change directory to the cloned git repo directory.

9. Install python libs to interact with Ethereum Network : pip install -r requirements.txt

10. Check docker is running : docker images

Build geth docker image

1. geth is Ethereum client written in Go.
2. We have a number of docker image options from custom docker image to official image.
3. Build Custom image with name local/ethereumbase:latest: docker build -t "local/ethereumbase:latest" -f ./Dockerfile .
4. Instead to use official Dockerfile-official-alltools-image build with docker build -t "ocal/ethereumbase:latest" -f ./Dockerfile-official-alltools-image .
5. Check Docker image docker images

Start network

• In bash shell change directory to cloned directory.
• ./deploy
• It will start
  • geth nodes : one bootnode, two miners and one eth node to interact : check Container IDs with docker ps
  • create a bridge network "ether_priv_net" between containers : check IP with docker network ls
  • disk volumes per nodes named as "bootnode_vol", "miner_1_vol" and so on : check with docker volume ls
  • Note: genesis.json is present in common folder
• This network has 9 prefilled accounts. Check keystore.
  • Out of that first four are used by bootnode, 2 miners & 1 eth node.
  • Google Genesis ethereum
  • What is Mining in ethereum ?

Interact with network using command line in nodes

• Miner node
  • Initial DAG creation will take 5/10 mins. Miner nodes will create initial DAG
  • check miner logs. On bash run docker log miner_1
  • SAMPLE LOG

  Generating DAG in progress               epoch=0 percentage=99 elapsed=19m41.071s
  Generating ethash verification cache     epoch=1 percentage=3  elapsed=3.284s
  

• Eth client node
  • Mean while check accounts and balance on eth node
  • attach to eth node's geth console : docker exec -it eth geth attach
  • use geth console to check that block count is increasing each 10 sec as configured in genesis
  • use the below commands one by one.

  eth.blockNumber
  # might output 16 
  eth.hashrate
  # 10
  eth.accounts
  #["0xa4b5db581bdee808c1896fac99ff22074885b079", "0x085db52a09584a953fab3046db4dd19474affc33", "0xe8c330a9112191ddcd65dd10f7ec60f32ab2067e", "0xf8ae31b2f7e68c36fff1370326aa6a7a9c586d69", "0x7eb19dbc863aa4f2e601b0e736a6000acc0e14b2", "0xc513ce206b0cd02b12b85796f87f6505cbf0e6f5"]
  eth.getBalance(eth.accounts[0])
  

  • In this non bootnode check that it shows 2 peers admin.peers
  • Check your own address admin.nodeInfo.enode
  • Check below for more examples.

Stop network

• In bash shell from cloned directory give ./shutdown
• Note we created docker disk volumes, ./shutdown will not clear these.
• Thus giving ./deploy to a ./shutdown network will start iit from last mined block.

Cleanup network

• In bash shell from cloned directory give ./shutdown then ./cleanup

Console Example of Transcation : sending ether (crypto currency) to another address

• Login to client node docker exec -it eth geth attach
• eth.coinbase will produce your coinbase / purse hash. Example "0xa4b5db581bdee808c1896fac99ff22074885b079"
• eth.accounts will show list of all accounts on this network.
  • These are visible here because they were add in genesis block
  • Output : ["0xa4b5db581bdee808c1896fac99ff22074885b079", "0x085db52a09584a953fab3046db4dd19474affc33", "0xe8c330a9112191ddcd65dd10f7ec60f32ab2067e", "0xf8ae31b2f7e68c36fff1370326aa6a7a9c586d69", "0x7eb19dbc863aa4f2e601b0e736a6000acc0e14b2", "0xc513ce206b0cd02b12b85796f87f6505cbf0e6f5"]
• Send some ether to another account. It will output transaction hash.

Output : "0xf2b0f7ef1ee3dd6c9ae5857ca481354efa46277a241e3d5369c070a6a577358e"

• using the Output hash get transaction receipt.
  • Note Transaction processing time == mining rate of block
  • for a unprocessed transaction

  eth.getTransactionReceipt("0xf2b0f7ef1ee3dd6c9ae5857ca481354efa46277a241e3d5369c070a6a577358e")
  
  Error: unknown transaction
      at web3.js:3143:20
      at web3.js:6347:15
      at web3.js:5081:36
      at <anonymous>:1:1
  

  • processed transaction

  eth.getTransactionReceipt("0xf2b0f7ef1ee3dd6c9ae5857ca481354efa46277a241e3d5369c070a6a577358e")
  {
    blockHash: "0xd58bfda2fb8800c0c7ad3ce32c2523b3526e5602f9a8c506f6df785955f0a41b",
    blockNumber: 24,
    contractAddress: null,
    cumulativeGasUsed: 21000,
    from: "0xa4b5db581bdee808c1896fac99ff22074885b079",
    gasUsed: 21000,
    logs: [],
    logsBloom: "0x00000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000",
    status: "0x1",
    to: "0xae17b64a594024b4df2158f804795cfba0d356f2",
    transactionHash: "0xf2b0f7ef1ee3dd6c9ae5857ca481354efa46277a241e3d5369c070a6a577358e",
    transactionIndex: 0
  }
  

Smart Contract

• Ethereum uses "Solidity" programing language & online Compiler named "remix".
• Code is quite comprehensible.
• I have pre-compiled my smart contract code online & put in the python script.
• This is another smart contract example.
• My solidity code with comments

  pragma solidity ^0.4.0;
  contract auid{
      /* Define variable value of the type string */
      string value;
      /* Define variable owner of the type address */
      address owner;
  
  
      /* CTOR : This runs when the contract is executed */
      /* This function is executed at initialization and sets the owner of the contract */
      function auid() public { owner = msg.sender; }
  
      /* DTOR : Function to recover the funds on the contract */
      function kill() public { if (msg.sender == owner) selfdestruct(owner); }
  
  
      /* Main function */
      function setvalue(string _value) public {
          value = _value;
      }
  
      /* Constant function => no charges to user to execute */
      function getvalue() public constant returns (string) {
          return value;
      }
  
      ////////////////////////////////////////////////
      // BELOW EXPERIMENTAL CODE SHOULD BE SKIPPED
      // we can log events
      // event setvalue
      /*
      // array of viewers : To Be Done
      address [] viewers;
  
      function transferOwnership( address newOwner ) public {
        owner = newOwner;
      }*/
  }
  

Python client code

• From cloned directory start python script interactively python -i main.py
• My python code JSONRPCBaseClient directly pushes compiled bytecode to deploy a smart contract.
  • JSONRPCBaseClient will connect to eth node on 127.0.0.1:8545
• In python console after first step select a password ``` password="UR_OWN_Password"
• Create user userId = createuser( password )
• Deploy contract fixed_contract_hash = a=deploy_contract( userId, password )
  • This operation will consume some gas ( actually smaller denomination of ether called wei ) because blockchain was modified.
    • "gas" is a proportion or a priority set by user. In this code I have defaulted the gas value to 1.
• Set LandRecord trans_receipt = setdata( userId, password, fixed_contract_hash )
  • Each modify ie set operation will also consume gas.
  • In my actual project we saved a hash string which translated to a secured file server URL.
  • This URL was meaningless outside our server.
• Get LandRecord getdata( fixed_contract_hash )
  • This doesn't modify blockchain so its free of any wei charge.