Class EventHandler

Called to indicate that a worker has just started.

:param worker: :class:`.Worker` object

Called to indicate that a worker command for a specific node (or key) has just started. Called for each node.

:param worker: :class:`.Worker` object

Available worker attributes:

* :attr:`.Worker.current_node` - node (or key)

Called to indicate that a worker has data to read from a specific node (or key).

:param worker: :class:`.Worker` object

Available worker attributes:

* :attr:`.Worker.current_node` - node (or key) * :attr:`.Worker.current_msg` - read message

Called to indicate that a worker has error to read on stderr from a specific node (or key).

:param worker: :class:`.Worker` object

Available worker attributes:

* :attr:`.Worker.current_node` - node (or key) * :attr:`.Worker.current_errmsg` - read error message

Called to indicate that some writing has been done by the worker to a
node on a given stream. This event is only generated when ``write()``
is previously called on the worker.

This handler may be called very often depending on the number of target
nodes, the amount of data to write and the block size used by the
worker.

Note: up to ClusterShell 1.6, this event handler wasn't implemented. To
properly handle ev_written after 1.6, the method signature must consist
of the following parameters:

:param worker: :class:`.Worker` object
:param node: node (or) key
:param sname: stream name
:param size: amount of bytes that has just been written to node/stream
    associated with this event

Called to indicate that a worker command for a specific node (or key) has just finished. Called for each node.

:param worker: :class:`.Worker` object

Available worker attributes:

* :attr:`.Worker.current_node` - node (or key) * :attr:`.Worker.current_rc` - command return code

Called to indicate that a worker has timed out (worker timeout only).

:param worker: :class:`.Worker` object

Called to indicate that a worker has just finished (it may already have failed on timeout).

:param worker: :class:`.Worker` object

Called to indicate that a message has been received on an EnginePort.

Used to deliver messages reliably between tasks.

:param port: EnginePort object on which a message has been received :param msg: the message object received

Called to indicate that a timer is firing.

:param timer: :class:`.EngineTimer` object that is firing