# Copyright 2017 Google Inc.

#

# Licensed under the Apache License, Version 2.0 (the "License");

# you may not use this file except in compliance with the License.

# You may obtain a copy of the License at

#

# http://www.apache.org/licenses/LICENSE-2.0

#

# Unless required by applicable law or agreed to in writing, software

# distributed under the License is distributed on an "AS IS" BASIS,

# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.

# See the License for the specific language governing permissions and

# limitations under the License.

"""This module contains various strategies for upscaling and downscaling

Bigtable."""

def _upscale_incremental_strategy(current_nodes):

"""Simple scaling strategy, increase nodes by 2."""

return current_nodes + 2

UPSCALE_STRATEGIES = {

'incremental': _upscale_incremental_strategy

}

"""UPSCALE_STRATEGIES contains a dict of functions for scaling Bigtable.

The function signature should accept the current number of nodes and return

the new number of nodes to scale to.

"""

def _downscale_incremental_strategy(current_nodes):

"""Simple downscale strategy: decrease nodes by 2."""

new_nodes = current_nodes - 2

if new_nodes < 3: # 3 is minimum number of CBT nodes

return 3

return new_nodes

DOWNSCALE_STRATEGIES = {

'incremental': _downscale_incremental_strategy

}

"""DOWNSCALE_STRATEGIES contains a dict of functions for scaling Bigtable.

The function signature should accept the current number of nodes and return

the new number of nodes to scale to.

"""