import cherrypy
import datetime
import time
from girder.models.notification import Notification, ProgressState
from girder.exceptions import ValidationException, RestException
[docs]class ProgressContext:
"""
This class is a context manager that can be used to update progress in a way
that rate-limits writes to the database and guarantees a flush when the
context is exited. This is a no-op if "on" is set to False, which is
meant as a convenience for callers. Any additional kwargs passed to this
constructor are passed through to the ``initProgress`` method of the
notification model.
:param on: Whether to record progress.
:type on: bool
:param interval: Minimum time interval at which to write updates to the
database, in seconds.
:type interval: int or float
:param user: The user creating this progress.
:type user: dict
:param title: The title for the task being tracked.
:type title: str
"""
def __init__(self, on, interval=0.5, **kwargs):
self.on = on
self.interval = interval
if on:
self._lastSave = time.time()
self.progress = Notification().initProgress(**kwargs)
def __enter__(self):
return self
def __exit__(self, excType, excValue, traceback):
"""
Once the context is exited, the progress is marked for deletion 30
seconds in the future, which should give all listeners time to poll and
receive the final state of the progress record before it is deleted.
"""
if not self.on:
return
if excType is None and excValue is None:
state = ProgressState.SUCCESS
message = 'Done'
else:
state = ProgressState.ERROR
message = 'Error'
if isinstance(excValue, (ValidationException, RestException)):
message = 'Error: ' + str(excValue)
Notification().updateProgress(
self.progress, state=state, message=message,
expires=datetime.datetime.utcnow() + datetime.timedelta(seconds=30)
)
[docs] def update(self, force=False, **kwargs):
"""
Update the underlying progress record. This will only actually save
to the database if at least self.interval seconds have passed since
the last time the record was written to the database. Accepts the
same kwargs as Notification.updateProgress.
:param force: Whether we should force the write to the database. Use
only in cases where progress may be indeterminate for a long time.
:type force: bool
"""
# Extend the response timeout, even if we aren't reporting the progress
setResponseTimeLimit()
if not self.on:
return
save = (time.time() - self._lastSave > self.interval) or force
self.progress = Notification().updateProgress(self.progress, save, **kwargs)
if save:
self._lastSave = time.time()
noProgress = ProgressContext(False)
[docs]def setResponseTimeLimit(duration=600, onlyExtend=True):
"""
If we are currently within a cherrypy response, extend the time limit. By
default, cherrypy (version < 12.0) responses will timeout after 300
seconds, so any activity which can take longer should call this function.
Note that for cherrypy responses that include streaming generator
functions, such as downloads, the timeout is only relevant until the first
``yield`` is reached. As such, long running generator responses do not
generally need to call this function.
@deprecated - remove this function once we pin to CherryPy >= 12.0
:param duration: additional duration in seconds to allow for the response.
:param onlyExtend: if True, only ever increase the timeout. If False, the
new duration always replaces the old one.
"""
# CherryPy 12.0 no longer has a timeout property on a response. Since we
# had only been using this to extend the time, if the timeout property is
# not present, do nothing.
if (cherrypy.response and getattr(cherrypy.response, 'time', None)
and getattr(cherrypy.response, 'timeout', None)):
newTimeout = time.time() - cherrypy.response.time + duration
if not onlyExtend or newTimeout > cherrypy.response.timeout:
cherrypy.response.timeout = newTimeout