Message handling

• When a message is received the msg_handler is called with:

  • 'job' (a dict of msg, received_time and ident)
  • The channel
  • msg_type
  • A function send_reply

• The msg_handler

  • determines the subshell_id and run mode.
  • obtains the handler from the kernel with the same name as the msg_type.
  • determines the run mode
  • creates cached version of the run_handler with a unique version per:
    • The handler
    • channel
    • subshell_id
    • send_reply (constant or per-channel)
  • Obtains the caller associated with the channel and schedules execution of the cached handler

Run mode

The run modes available are:

• RunMode.direct → async_kernel.caller.Caller.call_direct Run the request directly in the scheduler.
• RunMode.queue → async_kernel.caller.Caller.queue_call Run the request in a queue dedicated to the subshell, handler & channel.
• RunMode.task → async_kernel.caller.Caller.call_soon Run the request in a separate task.
• RunMode.thread → async_kernel.caller.Caller.to_thread Run the request in a separate worker thread.

These are the currently assigned run modes.

SocketID	shell	control
comm_close	direct	direct
comm_info_request	direct	direct
comm_msg	queue	queue
comm_open	direct	direct
complete_request	thread	thread
create_subshell_request	None	thread
debug_request	None	queue
delete_subshell_request	None	thread
execute_request	queue	queue
history_request	thread	thread
inspect_request	thread	thread
interrupt_request	direct	direct
is_complete_request	thread	thread
kernel_info_request	direct	direct
list_subshell_request	None	direct
shutdown_request	None	direct