==================================
Install chaincode programmatically
==================================

To install chaincode inside our application, we need to reach out to system chaincode called ``_lifecycle``.

Following piece of code can be taken as a reference:

.. code-block:: go
  :linenos:

  func InstallChaincode(network *client.Network, arguments *lifecycle.InstallChaincodeArgs) (*lifecycle.InstallChaincodeResult, error) {
    lifecycleChaincode := network.GetContract("_lifecycle")

    argumentsBytes, err := proto.Marshal(arguments)
    if err != nil {
      return nil, err
    }

    chaincodesBytes, err := lifecycleChaincode.EvaluateTransaction("InstallChaincode", string(argumentsBytes))
    if err != nil {
      return nil, err
    }

    installedChaincode := new(lifecycle.InstallChaincodeResult)
    err = proto.Unmarshal(chaincodesBytes, installedChaincode)
    if err != nil {
      return nil, err
    }

    return installedChaincode, nil
  }


Where:
  - ``lifecycle.InstallChaincodeArgs`` - protobuf struct that the ``InstallChaincode`` chaincode function expects while installing the chaincode (``lifecycle`` package is imported from ``"github.com/hyperledger/fabric-protos-go-apiv2/peer/lifecycle"``)
  - ``lifecycle.InstallChaincodeResult`` - the return type of ``InstallChaincode`` chaincode function

``lifecycle.InstallChaincodeArgs`` has ``ChaincodeInstallPackage`` field that we fill with the target chaincode. Take a look at this function usage:

.. code-block:: go
  :linenos:

  // ...

  arguments := lifecycle.InstallChaincodeArgs{ChaincodeInstallPackage: myChaincodeBytes}
  result, err := InstallChaincode(network, &arguments)

  fmt.Printf("Label: %v, Package id: %v", result.Label, result.PackageId)