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dfx nns

Reference

The dfx nns command is no longer part of dfx, and has now been turned into the dfx extension. In order to obtain it, please run dfx extension install nns.

Use the dfx nns subcommands to interact with the Network Nervous System.

The basic syntax for running dfx nns commands is:

dfx nns [subcommand] [flag]

Depending on the dfx nns subcommand you specify, additional arguments, options, and flags might apply. For reference information and examples that illustrate using dfx nns commands, select an appropriate command.

CommandDescription
importAdds the NNS canisters to the local dfx.json as remote canisters.
installDeploys NNS canisters to the local dfx server.
helpDisplays usage information message for a specified subcommand.

To view usage information for a specific subcommand, specify the subcommand and the --help flag. For example, to see usage information for dfx nns install, you can run the following command:

$ dfx nns install --help

dfx nns import​

Use the dfx nns import command to add the NNS canisters to the local dfx.json. It also downloads the did files and sets the canister IDs of the NNS cansiters so that you can make API calls to NNS canisters.

Basic usage​

$ dfx nns import

Flags​

You can use the following optional flags with the dfx nns import command.

FlagDescription
--network-mappingRenames networks when installing canister IDs.

Examples​

You can use the dfx nns import command to get did files and so query NNS canisters.

$ dfx nns import
$ dfx canister call --network ic nns-governance get_pending_proposals '()'

You can rename a network on import. For example, if you have test-ic set up as an alias of the ic network then you can set NNS canister IDs for test-ic with:

$ dfx nns import --network-mapping test-ic=ic

dfx nns install​

Use the dfx nns install command to install a local NNS. This provides local ledger and governance canisters as well as the GUI canisters Internet Identity and NNS-Dapp.

Basic usage​

The local network needs to be set up with a very specific configuration:

$ cat ~/.config/dfx/networks.json
{
  "local": {
    "bind": "127.0.0.1:8080",
    "type": "ephemeral",
    "replica": {
      "subnet_type": "system"
    }
  }
}

This is because:

  • The NNS canisters need to run on a system subnet.
  • Some canisters are compiled to run on only very specific canister IDs and hostname/port pairs.

In addition, the local dfx server needs to be clean:

$ dfx start --clean --background
$ dfx nns install

This is because NNS canisters need to be installed before any others.

Examples​

Example: Making API calls to the local NNS.​

$ dfx stop
$ dfx start --clean --background
$ dfx nns install
$ dfx nns import
$ dfx canister call --network ic nns-governance get_pending_proposals '()'

You can view the API calls that can be made for each NNS canister by looking at the interface definition files installed by dfx nns import in candid/*.did. The API methods are in the service section, which is usually located at the end of a .did file. It is easiest to start experimenting with methods that take no arguments.

Example: Accessing ICP on the command line​

Two accounts in the local ledger is initialized with ICP that can be used for testing. One uses a secp256k1 key, which is convenient for command line usage, another uses an ed25519 key, which is more convenient in web applications.

To use ICP on the command line:

  • Start dfx and install the NNS, as described in install.
  • Put this secret key into a file called ident-1.pem:
$ cat <<EOF >ident-1.pem
-----BEGIN EC PRIVATE KEY-----
MHQCAQEEICJxApEbuZznKFpV+VKACRK30i6+7u5Z13/DOl18cIC+oAcGBSuBBAAK
oUQDQgAEPas6Iag4TUx+Uop+3NhE6s3FlayFtbwdhRVjvOar0kPTfE/N8N6btRnd
74ly5xXEBNSXiENyxhEuzOZrIWMCNQ==
-----END EC PRIVATE KEY-----
EOF
  • Check the key: (optional)
$ openssl ec -in ident-1.pem -noout -text
  • Create an identity with that secret key:
$ dfx identity import ident-1 ident-1.pem
  • Now you can use the (toy) funds:
$ dfx ledger balance

To use ICP in an existing web application:

  const publicKey = "Uu8wv55BKmk9ZErr6OIt5XR1kpEGXcOSOC1OYzrAwuk=";
  const privateKey =
    "N3HB8Hh2PrWqhWH2Qqgr1vbU9T3gb1zgdBD8ZOdlQnVS7zC/nkEqaT1kSuvo4i3ldHWSkQZdw5I4LU5jOsDC6Q==";
  const identity = Ed25519KeyIdentity.fromKeyPair(
    base64ToUInt8Array(publicKey),
    base64ToUInt8Array(privateKey)
  );

  // If using node:
  const base64ToUInt8Array = (base64String: string): Uint8Array => {
    return Buffer.from(base64String, 'base64')
  };
  // If in a browser:
  const base64ToUInt8Array = (base64String: string): Uint8Array => {
    return Uint8Array.from(window.atob(base64String), (c) => c.charCodeAt(0));
  };
  • That identity can now make API calls, including sending ICP.