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

docker or docker-toolbox (windows) should be installed.
Install python 3.6
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
Install git
On Windows install git bash or cygwin. Linux users can skip this step.
Clone my repository : git clone https://github.com/Mastro-Geppetto/containerizedEthereumNetwork.git
Update python setuptools : pip install --upgrade setuptools
Change directory to the cloned git repo directory.
Install python libs to interact with Ethereum Network : pip install -r requirements.txt
Check docker is running : docker images

Build geth docker image

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

Mastro-Geppetto / containerizedEthereumNetwork