type NewAPIConnectionParams struct {
    // ControllerName is the name of the controller to connect to.
    ControllerName string

    // Store is the jujuclient.ClientStore from which the controller's
    // details will be fetched, and updated on address changes.
    Store jujuclient.ClientStore

    // OpenAPI is the function that will be used to open API connections.
    OpenAPI api.OpenFunc

    // DialOpts contains the options used to dial the API connection.
    DialOpts api.DialOpts

    // AccountDetails contains the account details to use for logging
    // in to the Juju API. If this is nil, then no login will take
    // place. If AccountDetails.Password and AccountDetails.Macaroon
    // are zero, the login will be as an external user.
    AccountDetails *jujuclient.AccountDetails

    // ModelUUID is an optional model UUID. If specified, the API connection
    // will be scoped to the model with that UUID; otherwise it will be
    // scoped to the controller.
    ModelUUID string
}

type UpdateControllerParams struct {
    // AgentVersion is the version of the controller agent.
    AgentVersion string

    // CurrentHostPorts are the available api addresses.
    CurrentHostPorts [][]network.HostPort

    // AddrConnectedTo (when set) is an API address that has been recently
    // connected to.
    AddrConnectedTo string

    // IPAddrConnected to (when set) is the IP address of AddrConnectedTo
    // that has been recently connected to.
    IPAddrConnectedTo string

    // DNSCache holds entries in the DNS cache.
    DNSCache map[string][]string

    // PublicDNSName (when set) holds the public host name of the controller.
    PublicDNSName *string

    // ControllerMachineCount (when set) is the total number of controller machines in the environment.
    ControllerMachineCount *int

    // MachineCount (when set) is the total number of machines in the models.
    MachineCount *int
}