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Build a private chain with one node

Neo-CLI supports generating blocks without consensus nodes, which means you can set up a private chain with one node. To simplify the process, you can directly download the project neo-express to run the private chain quickly.

Alternatively, you can build a private chain with one node from scratch, which will be elaborated in the following sections.

Prerequisites#

  1. Refer to Installation of NEO-CLI to install Neo-CLI. (Make sure you install the DBFTPlugin

  2. Run Neo-CLI and enter the command create wallet <path> to create a wallet, e.g. create wallet consensus.json

  3. Specify the wallet password and confirm.

  4. Record the wallet pubkey. This will be used in later steps.

Modifying the node configuration files#

Modifying config.json#

In config.json under the Neo-cli directory, make the following configurations:

  • In UnlockWallet specify the wallet path and wallet password.
  • Set IsActive as true.
  • Set ConsoleOutput and Active as true.
  • Set ValidatorsCount as 1.
  • In StandbyCommittee, enter the public key of the consensus.json wallet (Only one public key in StandbyCommittee represents the solo mode).

Here is an example：

{  "ApplicationConfiguration": {    "Logger": {      "Path": "Logs",      "ConsoleOutput": true,      "Active": true    },    "Storage": {      "Engine": "LevelDBStore",      "Path": "Data_LevelDB_{0}"    },    "P2P": {      "Port": 21333,      "WsPort": 21334    },    "UnlockWallet": {      "Path": "consensus.json",      "Password": "1",      "IsActive": true    },    "PluginURL": "https://github.com/neo-project/neo-modules/releases/download/v{1}/{0}.zip"  },  "ProtocolConfiguration": {    "Network": 5309138,    "MillisecondsPerBlock": 15000,    "MaxTraceableBlocks": 2102400,    "ValidatorsCount": 1,    "StandbyCommittee": [      "02ff249d06faaf0b5ba865e1531bfabe07f89aef39ab59082e3bc140be0318055d"    ],    "SeedList": []  }}

In the config.json under the Plugins\DBFTPlugin directory make the following change:

  • Set AutoStart as true, and set Network same as the Network in config.json under the Neo-cli directory.

Here is an example:

{  "PluginConfiguration": {    "RecoveryLogs": "ConsensusState",    "IgnoreRecoveryLogs": false,    "AutoStart": true,    "Network": 5309138,    "MaxBlockSize": 262144,    "MaxBlockSystemFee": 900000000000  }}

Starting the private chain#

note

If the node has downloaded Neo test net block files, you need to delete the Data folder before running Neo-CLI, otherwise the private chain will not be able to properly generate blocks.

To start the private chain, enter the neo-cli directory and run neo-cli.exe, or run the command line and enter dotnet neo-cli.dll. The private chain is set up successfully when it goes as shown below:

The private chain is terminated if you close the window.

Withdrawing NEO and GAS#

Using Neo-CLI to withdraw#

In the genesis block of the Neo network, 100 million NEO and 30 million GAS are generated. When the private chain is set up, you can withdraw those NEO and GAS from a multi-party address with Neo-CLI, to facilitate your blockchain development and testing.

  1. Copy another Neo-CLI directory as an external node.

  2. Add the consensus node tcp address (localhost:21333) to the seedlist field in the external node config.json.

  3. Modify the port in the external node config.json to avoid conflicting with other consensus node ports:

    {  "ApplicationConfiguration": {    "Logger": {      "Path": "Logs",      "ConsoleOutput": false,      "Active": false    },    "Storage": {      "Engine": "LevelDBStore",      "Path": "Data_LevelDB_{0}"    },    "P2P": {      "Port": 23333,      "WsPort": 23334    },    "UnlockWallet": {      "Path": "",      "Password": "",      "IsActive": false    },    "PluginURL": "https://github.com/neo-project/neo-modules/releases/download/v{1}/{0}.zip"  },  "ProtocolConfiguration": {    "Network": 5309138,    "MillisecondsPerBlock": 15000,    "MaxTraceableBlocks": 2102400,    "ValidatorsCount": 1,    "StandbyCommittee": [      "02ff249d06faaf0b5ba865e1531bfabe07f89aef39ab59082e3bc140be0318055d"    ],    "SeedList": [    "localhost:21333"    ]  }}

  4. Start the private chain and the external node

  5. From the external node command line, open the wallet consensus.json and enter import multisigaddress m pubkeys to create a multi-part signed address, where:

    m is 1 as the minimal signature number and pubkeys is the public key of consensus.json

import multisigaddress 1 02ff249d06faaf0b5ba865e1531bfabe07f89aef39ab59082e3bc140be0318055d

  1. Enter list asset，then you should see 100 million NEO and 30 million GAS displayed.

  2. Create a new wallet using the command create wallet and copy the wallet address.

  3. Open the wallet consensus.json again and transfer NEO and GAS to the new created wallet with the send command. For example, send neo NWu2gb7PzhZb4ci9LvW4gBYAQFMGb1s1o7 100000000, send gas NWu2gb7PzhZb4ci9LvW4gBYAQFMGb1s1o7 10000000.

note

The wallet that sends tokens should have enough GAS as a few fee (usually no more than 0.02 GAS) will be charged at the time of transfer.

For more Neo-CLI commands refer to CLI command reference.