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# Copyright 2024, The Android Open Source Project
#
# 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.
import hashlib
import logging
import os
def is_feature_enabled(
feature_name: str,
user_name: str,
enable_flag: str = None,
rollout_percent: int = 100,
) -> bool:
"""Determine whether the given feature is enabled.
Whether a given feature is enabled or not depends on two flags: 1) the
enable_flag that explicitly enable/disable the feature and 2) the rollout_flag
that controls the rollout percentage.
Args:
feature_name: name of the feature.
user_name: system user name.
enable_flag: name of the env var that enables/disables the feature
explicitly.
rollout_flg: name of the env var that controls the rollout percentage, the
value stored in the env var should be an int between 0 and 100 string
"""
if enable_flag:
if os.environ.get(enable_flag, "") == "false":
logging.info("feature: %s is disabled", feature_name)
return False
if os.environ.get(enable_flag, "") == "true":
logging.info("feature: %s is enabled", feature_name)
return True
hash_object = hashlib.sha256()
hash_object.update((user_name + feature_name).encode("utf-8"))
hash_number = int(hash_object.hexdigest(), 16) % 100
return hash_number < rollout_percent
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