Enforce DailyFlowRequestLimit and FlowDuplicateInterval.

    Look at the flows that have run on this client recently and check
    we aren't exceeding our limits. Raises if limits will be exceeded by running
    the specified flow.

    Args:
      client_id: client URN
      user: username string
      flow_name: flow name string
      flow_args: flow args rdfvalue for the flow being launched
      token: acl token

    Raises:
      DailyFlowRequestLimitExceededError: if the user has already run
        API.DailyFlowRequestLimit on this client in the previous 24h.
      DuplicateFlowError: an identical flow was run on this machine by a user
        within the API.FlowDuplicateInterval

def EnforceLimits(self, client_id, user, flow_name, flow_args, token=None):
    """Enforce DailyFlowRequestLimit and FlowDuplicateInterval.

    Look at the flows that have run on this client recently and check
    we aren't exceeding our limits. Raises if limits will be exceeded by running
    the specified flow.

    Args:
      client_id: client URN
      user: username string
      flow_name: flow name string
      flow_args: flow args rdfvalue for the flow being launched
      token: acl token

    Raises:
      DailyFlowRequestLimitExceededError: if the user has already run
        API.DailyFlowRequestLimit on this client in the previous 24h.
      DuplicateFlowError: an identical flow was run on this machine by a user
        within the API.FlowDuplicateInterval
    """
    if not self.dup_interval and not self.daily_req_limit:
      return

    now = rdfvalue.RDFDatetime.Now()
    yesterday = now - rdfvalue.Duration("1d")
    dup_boundary = now - self.dup_interval
    min_create_time = min(yesterday, dup_boundary)

    flow_count = 0
    flows = self._LoadFlows(client_id, min_create_time, token=token)

    if flow_args is None:
      flow_args = flow.EmptyFlowArgs()

    for flow_obj in flows:
      if (flow_obj.create_time > dup_boundary and
          flow_obj.flow_class_name == flow_name and flow_obj.args == flow_args):
        raise DuplicateFlowError(
            "Identical %s already run on %s at %s" %
            (flow_name, client_id, flow_obj.create_time),
            flow_id=flow_obj.flow_id)

      # Filter for flows started by user within the 1 day window.
      if flow_obj.creator == user and flow_obj.create_time > yesterday:
        flow_count += 1

    # If limit is set, enforce it.
    if self.daily_req_limit and flow_count >= self.daily_req_limit:
      raise DailyFlowRequestLimitExceededError(
          "%s flows run since %s, limit: %s" %
          (flow_count, yesterday, self.daily_req_limit))