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# Copyright (c) 2016 Weitian LI <liweitianux@live.com>
# MIT license
"""
Handle the "console" type of messages from the client.
"""
import logging
import tornado.ioloop
import tornado.gen
from tornado.escape import json_decode, json_encode
from .base import BaseRequestHandler
from .log import WebSocketLogHandler
logger = logging.getLogger(__name__)
class ConsoleAJAXHandler(BaseRequestHandler):
"""
Handle the AJAX requests from the client to control the tasks.
"""
# Allow only one task running at the same time
onetask_only = True
def initialize(self):
"""Hook for subclass initialization. Called for each request."""
self.configs = self.application.configmanager
self.status = self.application.task_status
# NOTE:
# Use ``IOLoop.instance`` instead of ``IOLoop.current``, since we
# will need to communicate with the main thread (e.g., callback)
# from another thread, which executes the submitted task.
self.io_loop = tornado.ioloop.IOLoop.instance()
@tornado.web.authenticated
def get(self):
"""
Handle the READ-ONLY tasks operations.
Supported actions:
- get: Get the current status of tasks.
"""
action = self.get_argument("action", "get")
if action == "get":
response = {"status": self.status}
success = True
else:
# ERROR: bad action
success = False
reason = "Bad request action: {0}".format(action)
#
if success:
logger.debug("Response: {0}".format(response))
self.set_header("Content-Type", "application/json; charset=UTF-8")
self.write(json_encode(response))
else:
logger.warning("Request failed: {0}".format(reason))
self.send_error(400, reason=reason)
@tornado.web.authenticated
def post(self):
"""
Handle the READ-WRITE task operations.
XXX/TODO:
* How to kill the submitted task? (force kill thread?)
Supported actions:
- start: Start the default or specified task.
- stop: Stop the running task (TODO/XXX)
"""
request = json_decode(self.request.body)
logger.debug("Received request: {0}".format(request))
action = request.get("action")
if action == "start":
task = request.get("task")
kwargs = request.get("kwargs", {})
success, reason = self._start_task(task=task, kwargs=kwargs)
elif action == "stop":
success = False
reason = "NOT implemented action: {0}".format(action)
else:
# ERROR: bad action
success = False
reason = "Bad request action: {0}".format(action)
#
if success:
response = {"status": self.status}
logger.debug("Response: {0}".format(response))
self.set_header("Content-Type", "application/json; charset=UTF-8")
self.write(json_encode(response))
else:
logger.warning("Request failed: {0}".format(reason))
self.send_error(400, reason=reason)
# FIXME/XXX:
# * How to call this task asynchronously ??
def _start_task(self, task=None, kwargs={}):
"""
Start the task by submitting it to the executor.
Parameters
----------
task : str, optional
The name of the task to be started.
If not specified, then start the default task.
NOTE:
Currently only support the default (``None``) and ``test`` tasks.
kwargs : dict, optional
Keyword arguments to be passed to the task.
Returns
-------
success : bool
Whether the task successfully finished?
error : str
Error message if the task failed
"""
TASKS = {
None: self._task_default, # default task
"test": self._task_test,
}
try:
f_task = TASKS[task]
except KeyError:
success = False
error = "Unknown task: {0}".format(task)
logger.warning(error)
return (success, error)
#
if self.onetask_only and self.status["running"]:
success = False
error = "Task already running and only one task allowed"
logger.warning(error)
else:
logger.info("Submit the task to the executor ...")
self.status["running"] = True
self.status["finished"] = False
# Also push the logging messages to clients through WebSocket
self._add_wsloghandler()
future = self.application.executor.submit(f_task, **kwargs)
self.io_loop.add_future(future, self._task_callback)
success, error = future.result()
return (success, error)
def _task_default(self, **kwargs):
"""
The default task that this console manages, which performs
the foregrounds simulations.
Returns
-------
success : bool
Whether the task successfully finished?
error : str
Error message if the task failed
NOTE
----
The task is synchronous and may be computationally intensive
(i.e., CPU-bound rather than IO/event-bound), therefore,
threads (or processes) are required to make it non-blocking
(i.e., asynchronous).
References:
[1] https://stackoverflow.com/a/32164711/4856091
"""
logger.info("Console DEFAULT task: START ...")
logger.info("Preparing to start foregrounds simulations ...")
logger.info("Importing modules + Numba JIT, waiting ...")
from ..foregrounds import Foregrounds
#
logger.info("Checking the configurations ...")
self.configs.check_all()
fg = Foregrounds(self.configs)
fg.preprocess()
fg.simulate()
fg.postprocess()
logger.info("Foregrounds simulations DONE!")
logger.info("Console DEFAULT task: DONE!")
# NOTE: always return a tuple of (success, error)
return (True, None)
def _task_test(self, **kwargs):
"""
Test task ...
"""
import time
logger.info("Console TEST task: START ...")
for i in range(kwargs["time"]):
logger.info("Console TEST task: slept {0} seconds ...".format(i))
time.sleep(1)
logger.info("Console TEST task: DONE!")
return (True, None)
def _task_callback(self, future):
"""Callback function executed when the task finishes"""
logger.info("Task finished! Callback ...")
self.status["running"] = False
self.status["finished"] = True
self._remove_wsloghandler()
logger.info("Callback DONE!")
def _add_wsloghandler(self):
"""
Add a WebSocket handler to the logging handlers, which will capture
all the logging messages and push them to the client.
"""
self.wsloghandler = WebSocketLogHandler(self.application.websockets,
msg_type="console")
root_logger = logging.getLogger()
root_logger.addHandler(self.wsloghandler)
logger.info("Added the WebSocket logging handler")
def _remove_wsloghandler(self):
"""Remove the WebSocket logging handler"""
root_logger = logging.getLogger()
root_logger.removeHandler(self.wsloghandler)
logger.info("Removed the WebSocket logging handler")
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