refactor config loading

- improve DRY
- alter logging
- allow extensibility
- add foundation for environment variables as config

common/config.py

@@ -1,6 +1,8 @@
 import yaml
 import pathlib
 from loguru import logger
+from mergedeep import merge, Strategy
+from typing import Any
 
 from common.utils import unwrap
 
@@ -8,61 +10,66 @@ from common.utils import unwrap
 GLOBAL_CONFIG: dict = {}
 
 
-def from_file(config_path: pathlib.Path):
-    """Sets the global config from a given file path"""
+def load(arguments: dict[str, Any]):
+    """load the global application config"""
     global GLOBAL_CONFIG
 
+    # config is applied in order of items in the list
+    configs = [
+        from_file(pathlib.Path("config.yml")),
+        from_environment(),
+        from_args(arguments),
+    ]
+
+    GLOBAL_CONFIG = merge({}, *configs, strategy=Strategy.REPLACE)
+
+def from_file(config_path: pathlib.Path) -> dict[str, Any]:
+    """loads config from a given file path"""
+
+    # try loading from file
     try:
         with open(str(config_path.resolve()), "r", encoding="utf8") as config_file:
-            GLOBAL_CONFIG = unwrap(yaml.safe_load(config_file), {})
+            return unwrap(yaml.safe_load(config_file), {})
+    except FileNotFoundError:
+        logger.info("The config.yml file cannot be found")
     except Exception as exc:
         logger.error(
-            "The YAML config couldn't load because of the following error: "
-            f"\n\n{exc}"
-            "\n\nTabbyAPI will start anyway and not parse this config file."
+            f"The YAML config couldn't load because of the following error:\n\n{exc}"
         )
-        GLOBAL_CONFIG = {}
+
+    # if no config file was loaded
+    return {}
 
 
-def from_args(args: dict):
-    """Overrides the config based on a dict representation of args"""
+def from_args(args: dict[str, Any]) -> dict[str, Any]:
+    """loads config from the provided arguments"""
+    config = {}
 
     config_override = unwrap(args.get("options", {}).get("config"))
     if config_override:
-        logger.info("Attempting to override config.yml from args.")
-        from_file(pathlib.Path(config_override))
-        return
+        logger.info("Config file override detected in args.")
+        config = from_file(pathlib.Path(config_override))
+        return config  # Return early if loading from file
 
-    # Network config
-    network_override = args.get("network")
-    if network_override:
-        cur_network_config = network_config()
-        GLOBAL_CONFIG["network"] = {**cur_network_config, **network_override}
+    for key in ["network", "model", "logging", "developer", "embeddings"]:
+        override = args.get(key)
+        if override:
+            if key == "logging":
+                # Strip the "log_" prefix from logging keys if present
+                override = {k.replace("log_", ""): v for k, v in override.items()}
+            config[key] = override
 
-    # Model config
-    model_override = args.get("model")
-    if model_override:
-        cur_model_config = model_config()
-        GLOBAL_CONFIG["model"] = {**cur_model_config, **model_override}
+    return config
 
-    # Generation Logging config
-    logging_override = args.get("logging")
-    if logging_override:
-        cur_logging_config = logging_config()
-        GLOBAL_CONFIG["logging"] = {
-            **cur_logging_config,
-            **{k.replace("log_", ""): logging_override[k] for k in logging_override},
-        }
 
-    developer_override = args.get("developer")
-    if developer_override:
-        cur_developer_config = developer_config()
-        GLOBAL_CONFIG["developer"] = {**cur_developer_config, **developer_override}
+def from_environment() -> dict[str, Any]:
+    """loads configuration from environment variables"""
 
-    embeddings_override = args.get("embeddings")
-    if embeddings_override:
-        cur_embeddings_config = embeddings_config()
-        GLOBAL_CONFIG["embeddings"] = {**cur_embeddings_config, **embeddings_override}
+    # TODO: load config from environment variables
+    # this means that we can have host default to 0.0.0.0 in docker for example
+    # this would also mean that docker containers no longer require a non
+    # default config file to be used
+    return {}
 
 
 def sampling_config():