Introduce code from Rust monorepo. This is a mess

tts/nemo/utils/env_var_parsing.py

@@ -0,0 +1,207 @@
+# The MIT Licence (MIT)
+#
+# Copyright (c) 2016 YunoJuno Ltd
+#
+# Permission is hereby granted, free of charge, to any person obtaining a copy
+# of this software and associated documentation files (the "Software"), to deal
+# in the Software without restriction, including without limitation the rights
+# to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+# copies of the Software, and to permit persons to whom the Software is
+# furnished to do so, subject to the following conditions:
+#
+# The above copyright notice and this permission notice shall be included in all
+# copies or substantial portions of the Software.
+#
+# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+# SOFTWARE.
+#
+# Vendored dependency from : https://github.com/yunojuno/python-env-utils/blob/master/env_utils/utils.py
+#
+#
+# Modified by NVIDIA
+#
+# Copyright (c) 2020, NVIDIA CORPORATION.  All rights reserved.
+#
+# 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 decimal
+import json
+import os
+
+from dateutil import parser
+
+__all__ = [
+    "get_env",
+    "get_envbool",
+    "get_envint",
+    "get_envfloat",
+    "get_envdecimal",
+    "get_envdate",
+    "get_envdatetime",
+    "get_envlist",
+    "get_envdict",
+    "CoercionError",
+    "RequiredSettingMissingError",
+]
+
+
+class CoercionError(Exception):
+    """Custom error raised when a value cannot be coerced."""
+
+    def __init__(self, key, value, func):
+        msg = "Unable to coerce '{}={}' using {}.".format(key, value, func.__name__)
+        super(CoercionError, self).__init__(msg)
+
+
+class RequiredSettingMissingError(Exception):
+    """Custom error raised when a required env var is missing."""
+
+    def __init__(self, key):
+        msg = "Required env var '{}' is missing.".format(key)
+        super(RequiredSettingMissingError, self).__init__(msg)
+
+
+def _get_env(key, default=None, coerce=lambda x: x, required=False):
+    """
+    Return env var coerced into a type other than string.
+    This function extends the standard os.getenv function to enable
+    the coercion of values into data types other than string (all env
+    vars are strings by default).
+    Args:
+        key: string, the name of the env var to look up
+    Kwargs:
+        default: the default value to return if the env var does not exist. NB the
+            default value is **not** coerced, and is assumed to be of the correct type.
+        coerce: a function that is used to coerce the value returned into
+            another type
+        required: bool, if True, then a RequiredSettingMissingError error is raised
+            if the env var does not exist.
+    Returns the env var, passed through the coerce function
+    """
+    try:
+        value = os.environ[key]
+    except KeyError:
+        if required is True:
+            raise RequiredSettingMissingError(key)
+        else:
+            return default
+
+    try:
+        return coerce(value)
+    except Exception:
+        raise CoercionError(key, value, coerce)
+
+
+# standard type coercion functions
+def _bool(value):
+    if isinstance(value, bool):
+        return value
+
+    return not (value is None or value.lower() in ("false", "0", "no", "n", "f", "none"))
+
+
+def _int(value):
+    return int(value)
+
+
+def _float(value):
+    return float(value)
+
+
+def _decimal(value):
+    return decimal.Decimal(value)
+
+
+def _dict(value):
+    return json.loads(value)
+
+
+def _datetime(value):
+    return parser.parse(value)
+
+
+def _date(value):
+    return parser.parse(value).date()
+
+
+def get_env(key, *default, **kwargs):
+    """
+    Return env var.
+    This is the parent function of all other get_foo functions,
+    and is responsible for unpacking args/kwargs into the values
+    that _get_env expects (it is the root function that actually
+    interacts with environ).
+    Args:
+        key: string, the env var name to look up.
+        default: (optional) the value to use if the env var does not
+            exist. If this value is not supplied, then the env var is
+            considered to be required, and a RequiredSettingMissingError
+            error will be raised if it does not exist.
+    Kwargs:
+        coerce: a func that may be supplied to coerce the value into
+            something else. This is used by the default get_foo functions
+            to cast strings to builtin types, but could be a function that
+            returns a custom class.
+    Returns the env var, coerced if required, and a default if supplied.
+    """
+    assert len(default) in (0, 1), "Too many args supplied."
+    func = kwargs.get('coerce', lambda x: x)
+    required = len(default) == 0
+    default = default[0] if not required else None
+    return _get_env(key, default=default, coerce=func, required=required)
+
+
+def get_envbool(key, *default):
+    """Return env var cast as boolean."""
+    return get_env(key, *default, coerce=_bool)
+
+
+def get_envint(key, *default):
+    """Return env var cast as integer."""
+    return get_env(key, *default, coerce=_int)
+
+
+def get_envfloat(key, *default):
+    """Return env var cast as float."""
+    return get_env(key, *default, coerce=_float)
+
+
+def get_envdecimal(key, *default):
+    """Return env var cast as Decimal."""
+    return get_env(key, *default, coerce=_decimal)
+
+
+def get_envdate(key, *default):
+    """Return env var as a date."""
+    return get_env(key, *default, coerce=_date)
+
+
+def get_envdatetime(key, *default):
+    """Return env var as a datetime."""
+    return get_env(key, *default, coerce=_datetime)
+
+
+def get_envlist(key, *default, **kwargs):
+    """Return env var as a list."""
+    separator = kwargs.get('separator', ' ')
+    return get_env(key, *default, coerce=lambda x: x.split(separator))
+
+
+def get_envdict(key, *default):
+    """Return env var as a dict."""
+    return get_env(key, *default, coerce=_dict)