Enhance code quality

trolldb/cli.py

@@ -9,7 +9,7 @@
 from posttroll.subscriber import create_subscriber_from_dict_config
 from pydantic import FilePath
 
-from trolldb.config.config import AppConfig, parse_config_yaml_file
+from trolldb.config.config import AppConfig, parse_config
 from trolldb.database.mongodb import MongoDB, mongodb_context
 
 
@@ -62,8 +62,7 @@ async def record_messages(config: AppConfig) -> None:
 
 async def record_messages_from_config(config_file: FilePath) -> None:
     """Record messages into the database, getting the configuration from a file."""
-    config = parse_config_yaml_file(config_file)
-    await record_messages(config)
+    await record_messages(parse_config(config_file))
 
 
 async def record_messages_from_command_line(args=None) -> None:

trolldb/config/config.py

@@ -10,17 +10,18 @@
 
 import errno
 import sys
+from os import PathLike
 from typing import Any, NamedTuple
 
 from bson import ObjectId
 from bson.errors import InvalidId
 from loguru import logger
-from pydantic import AnyUrl, BaseModel, Field, FilePath, MongoDsn, ValidationError, validate_call
+from pydantic import AnyUrl, BaseModel, MongoDsn, PositiveFloat, ValidationError, validate_call
 from pydantic.functional_validators import AfterValidator
 from typing_extensions import Annotated
-from yaml import safe_load
+from yaml import parser, safe_load
 
-Timeout = Annotated[float, Field(ge=0)]
+Timeout = PositiveFloat
 """A type hint for the timeout in seconds (non-negative float)."""
 
 
@@ -108,37 +109,38 @@ class AppConfig(BaseModel):
     subscriber: SubscriberConfig
 
 
-@validate_call
-def parse_config_yaml_file(filename: FilePath) -> AppConfig:
-    """Parses and validates the configurations from a YAML file.
+@logger.catch(onerror=lambda _: sys.exit(1))
+def parse_config(file: int | str | bytes | PathLike[str] | PathLike[bytes]) -> AppConfig:
+    """Parses and validates the configurations from a YAML file (descriptor).
 
     Args:
-        filename:
-            The filename of a valid YAML file which holds the configurations.
+        file:
+            A path-like object (``str`` or ``bytes``) or an integer file descriptor. This will be directly passed to the
+            ``open()`` function. For example, it can be the filename (absolute or relative) of a valid YAML file which
+            holds the configurations.
 
     Returns:
         An instance of :class:`AppConfig`.
-
-    Raises:
-        ParserError:
-            If the file cannot be properly parsed.
-
-        ValidationError:
-            If the ``filename`` is not of type ``FilePath``.
-
-        ValidationError:
-            If the successfully parsed file fails the validation, i.e. its schema or the content does not conform to
-            :class:`AppConfig`.
     """
-    logger.info("Attempt to parse the YAML file ...")
-    with open(filename, "r") as file:
-        config = safe_load(file)
+    try:
+        logger.info("Attempt to parse the YAML file ...")
+        with open(file, "r") as f:
+            config = safe_load(f)
+    except parser.ParserError as e:
+        logger.error(f"The file could not be parsed: {e}")
+        sys.exit(errno.EIO)
+    except (OSError, FileNotFoundError) as e:
+        logger.error(f"The file (descriptor) could not be found or opened: {e}")
+        sys.exit(errno.EIO)
+
     logger.info("Parsing YAML file is successful.")
+
     try:
         logger.info("Attempt to validate the parsed YAML file ...")
         config = AppConfig(**config)
-        logger.info("Validation of the parsed YAML file is successful.")
-        return config
     except ValidationError as e:
         logger.error(e)
         sys.exit(errno.EIO)
+
+    logger.info("Validation of the parsed YAML file is successful.")
+    return config