Ethereum Blockchain (POA)

Create a blockchain

To create a blockchain, we first create the EthereumService, and then create a blockchain inside this service. The service supports multiple chains.

eth = EthereumService()
blockchain = eth.createBlockchain(chainName="POA", consensus=ConsensusMechanism.POA)

Create pre-funded accounts (add to the genesis block)

Each Ethereum node will have at least one accounts on it, and more can be created. The system use a set of default values to create and configure these accounts. Users can replace these default values with their own values.

mnemonic, _, _= blockchain.getEmuAccountParameters()
blockchain.setEmuAccountParameters(mnemonic=mnemonic, balance=1000, \
        total_per_node = total_accounts_per_node)

Users can also add arbitrary pre-funded account to the blockchain.

blockchain.addLocalAccount(address='0xF5406927254d2dA7F7c28A61191e3Ff1f2400fe9',
                           balance=30)

All the accounts created during the build time will be added (along with their balance) to the genesis block. Therefore, their balances are recognized.

For detailed account management instructions, see this manual

Create Ethereum Nodes

To create an Ethereum node, we just need to provide a node name (virtual node), and use the following API.

e = blockchain.createNode('node0')

Each node can be configured and customized using the provided APIs. See the EthereumServer class for the supported APIs.

Other useful APIs

These APIs are not used in this example, but they might be useful to satisfy additional emulation needs.

• Set custom geth command option: for commonly-used options, we already have APIs to set them. However, for options not covered by these APIs, users can use this generic API to set them.

  eth_node.setCustomGethCommandOption("--http --http.addr 0.0.0.0")
  

• Use custom geth binary file: some users want to run a modified version of the geth software on a particular node. They can do this using the following API.

  eth_node.setCustomGeth("./custom_geth_binary")
  

Create Faucet and Information Servers

In this example, we also create a faucet server and a utility server. These two servers are not used in this example, but they are used by other examples. Because many applications require these two servers, they are two essential elements in the SEED blockchain emulator.

These two servers are not used in this example. The faucet server is used in the example D20_faucet, while the utility server is used in the example D21_deploy_contract to help deploy smart contracts.

Binding to Physical Nodes

All the virtual nodes need to be bound to physical nodes. We have implemented an API called getAllServerNames to make it easy to get all the server names, including the ethereum nodes, the faucet nodes, and the init-and-info servers.

for _, servers in blockchain.getAllServerNames().items():
    for server in servers:
       emu.addBinding(Binding(server))

In our example, we did not set any filter in the binding, so the binding will be random, i.e., each virtual node will be randomly bound to a physical node.

Supported platforms

As of 5/25/2024, SEED Emulation Ethereum layer supports AMD platforms and partially supports ARM platforms. Please see details below.