Move files

great_ai/utilities/config_file/__init__.py

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+from .config_file import ConfigFile
+from .parse_error import ParseError

great_ai/utilities/config_file/config_file.py

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+import os
+from pathlib import Path
+from typing import Dict, Iterable, Tuple, Union
+
+from ..logger import get_logger
+from .parse_error import ParseError
+from .pattern import pattern
+
+ENVIRONMENT_VARIABLE_KEY_PREFIX = "ENV"
+
+logger = get_logger("ConfigFile")
+
+
+class ConfigFile:
+    def __init__(self, path: Union[Path, str]) -> None:
+        if not isinstance(path, Path):
+            path = Path(path)
+
+        if not path.exists():
+            raise FileNotFoundError(path.absolute())
+
+        self._path = path
+        self._key_values: Dict[str, str] = {}
+
+        self._parse()
+
+    def _parse(self):
+        with open(self._path, encoding="utf-8") as f:
+            lines: str = f.read()
+
+        matches = pattern.findall(lines)
+        for key, *values in matches:
+            try:
+                value = next(v for v in values if v)
+            except StopIteration:
+                raise ParseError(
+                    f"Cannot parse config file ({self._path.absolute()}), error at key `{key}`"
+                )
+
+            already_exists = key in self._key_values
+            if already_exists and not value.startswith(
+                f"{ENVIRONMENT_VARIABLE_KEY_PREFIX}:"
+            ):
+                raise KeyError(
+                    f"Key `{key}` has been already defined and its value is `{self._key_values[key]}`"
+                )
+
+            if value.startswith(f"{ENVIRONMENT_VARIABLE_KEY_PREFIX}:"):
+                _, value = value.split(":")
+                if value not in os.environ:
+                    issue = f'The value of `{key}` contains the "{ENVIRONMENT_VARIABLE_KEY_PREFIX}` prefix but `{value}` is not defined as an environment variable'
+                    if already_exists:
+                        logger.warning(
+                            f"{issue}, using the default value defined above (`{self._key_values[key]}`)"
+                        )
+                        continue
+                    else:
+                        raise KeyError(
+                            f"{issue} and no default value has been provided"
+                        )
+                else:
+                    value = os.environ[value]
+
+            self._key_values[key] = value
+
+    def __getattr__(self, key: str) -> str:
+        if key in self._key_values:
+            return self._key_values[key]
+        raise KeyError(
+            f"Key `{key}` is not found in configuration file ({self._path.absolute()})"
+        )
+
+    __getitem__ = __getattr__
+
+    def __iter__(self) -> Iterable[Tuple[str, str]]:
+        return iter(self._key_values)
+
+    def __len__(self) -> int:
+        return len(self._key_values)
+
+    def keys(self):
+        return self._key_values.keys()
+
+    def values(self):
+        return self._key_values.values()
+
+    def items(self):
+        return self._key_values.items()
+
+    def __repr__(self):
+        return f"{type(self).__name__}(path={self._path}) {self._key_values}"

great_ai/utilities/config_file/parse_error.py

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+class ParseError(Exception):
+    pass

great_ai/utilities/config_file/pattern.py

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+import re
+
+pattern = re.compile(
+    r"""
+        (?:^|\n)        # new key-value pairs must start on a new line
+        \s*             # leading whitespace is allowed
+        (?!\#)          # the key cannot start with a `#` symbol
+        (\w+?)          # then comes the key
+        \s*=\s*         # the key and value are separated by an equal sign
+        (?:             # then comes the value
+              "([^"]*)"   # the value can be surrounded by quotes: "value"
+            | '([^']*)'   # the value can be surrounded by quotes: 'value'
+            | `([^`]*)`   # the value can be surrounded by quotes: `value`
+            | ([^#\n]*?)  # or it is bare, in that case, the trailing whitespace is ignored
+        )
+        \s*(?:\#.*)?    # comments can be added with the `#` symbol
+        (?=\n|$)        # a key-value pairs are separated by new lines
+    """,
+    flags=re.UNICODE | re.VERBOSE,
+)