NAME

       ssh_agent  -  Callback  module  for  using  an  SSH  agent instead of the default ssh_file
       callback.

DESCRIPTION

       This module defines a callback handler for the communication with an SSH Agent and can  be
       used  to  replace  the default callback. This allows to issue signing requests to an agent
       that stores SSH private keys to perform authentication.

       Ssh_agent implements the ssh_client_key_api, to allow it to be used by setting the  option
       key_cb when starting a client (with for example ssh:connect, ssh:shell ).

             {key_cb, {ssh_agent, []}}

       The  agent  communication  is  established  through  a UNIX domain socket. By default, the
       socket path will be fetched from the SSH_AUTH_SOCK  environment  variable,  which  is  the
       default socket path in the agent implementation of OpenSSH.

       In order to set a different socket path the socket_path option can be set.

             {key_cb, {ssh_agent, [{socket_path, SocketPath}]}}

   Note:
       The  functions are Callbacks  for the SSH app. They are not intended to be called from the
       user's code!

DATA TYPES

   Options for the ssh_agent callback module
       socket_path_option() = {socket_path, string()}

              Sets the socket path for the communication with the agent.

       timeout_option() = {timeout, integer()}

              Sets the time-out in milliseconds when communicating with the agent via the socket.
              The default value is 1000.

       call_ssh_file_option() = {call_ssh_file, atom()}

              The  module  which  the  add_host_key  and  is_host_key callbacks are delegated to.
              Defaults to the ssh_file module.

EXPORTS

       add_host_key(Host :: string(),
                    PublicKey :: public_key:public_key(),
                    Options) ->
                       ok | {error, Error :: term()}

       add_host_key(Host,
                    Port :: inet:port_number(),
                    PublicKey :: public_key:public_key(),
                    Options) ->
                       Result

              Types:

                 Host =
                     inet:ip_address() |
                     inet:hostname() |
                     [inet:ip_address() | inet:hostname()]
                 Options =
                     ssh_client_key_api:client_key_cb_options(call_ssh_file_option())
                 Result = ok | {error, Error :: term()}

              This callback is delegated to the ssh_file module.

       is_host_key(Key :: public_key:public_key(),
                   Host :: string(),
                   Algorithm :: ssh:pubkey_alg(),
                   Options) ->
                      boolean()

       is_host_key(Key :: public_key:public_key(),
                   Host,
                   Port :: inet:port_number(),
                   Algorithm :: ssh:pubkey_alg(),
                   Options) ->
                      boolean()

              Types:

                 Host =
                     inet:ip_address() |
                     inet:hostname() |
                     [inet:ip_address() | inet:hostname()]
                 Options =
                     ssh_client_key_api:client_key_cb_options(call_ssh_file_option())

              This callback is delegated to the ssh_file module.

       user_key(Algorithm :: ssh:pubkey_alg(), Options) -> Result

              Types:

                 Result =
                     {ok, public_key:private_key()} |
                     {ok, {ssh2_pubkey, PubKeyBlob :: binary()}} |
                     {error, string()}
                 Options =
                     ssh_client_key_api:client_key_cb_options(socket_path_option() |
                                                              timeout_option())

              Types and description

              See the api description in ssh_client_key_api, Module:user_key/2.