Add config file parser for MVT

src/mvt/common/config.py

@@ -0,0 +1,91 @@
+import os
+import uuid
+import yaml
+import json
+
+from typing import Tuple, Type
+from appdirs import user_config_dir
+from pydantic import AnyHttpUrl, Field
+from pydantic_settings import (
+    BaseSettings,
+    InitSettingsSource,
+    PydanticBaseSettingsSource,
+    SettingsConfigDict,
+    YamlConfigSettingsSource,
+)
+
+MVT_CONFIG_FOLDER = user_config_dir("mvt")
+MVT_CONFIG_PATH = os.path.join(MVT_CONFIG_FOLDER, "config.yaml")
+
+
+class MVTSettings(BaseSettings):
+    model_config = SettingsConfigDict(
+        env_prefix="MVT_", env_nested_delimiter="_", extra="ignore"
+    )
+    # Allow to decided if want to load environment variables
+    load_env: bool = Field(True, exclude=True)
+
+    # General settings
+    PYPI_UPDATE_URL: AnyHttpUrl = Field(
+        "https://pypi.org/pypi/mvt/json",
+        validate_default=False,
+    )
+    INDICATORS_UPDATE_URL: AnyHttpUrl = Field(
+        default="https://raw.githubusercontent.com/mvt-project/mvt-indicators/main/indicators.yaml",
+        validate_default=False,
+    )
+    NETWORK_ACCESS_ALLOWED: bool = True
+    NETWORK_TIMEOUT: int = 15
+
+    @classmethod
+    def settings_customise_sources(
+        cls,
+        settings_cls: Type[BaseSettings],
+        init_settings: InitSettingsSource,
+        env_settings: PydanticBaseSettingsSource,
+        dotenv_settings: PydanticBaseSettingsSource,
+        file_secret_settings: PydanticBaseSettingsSource,
+    ) -> Tuple[PydanticBaseSettingsSource, ...]:
+        sources = (
+            YamlConfigSettingsSource(settings_cls, MVT_CONFIG_PATH),
+            init_settings,
+        )
+        # Load env variables if enabled
+        if init_settings.init_kwargs.get("load_env", True):
+            sources = (env_settings,) + sources
+        return sources
+
+    def save_settings(
+        self,
+    ) -> None:
+        """
+        Save the current settings to a file.
+        """
+        if not os.path.isdir(MVT_CONFIG_FOLDER):
+            os.makedirs(MVT_CONFIG_FOLDER)
+
+        # Dump the settings to the YAML file
+        model_serializable = json.loads(self.model_dump_json(exclude_defaults=True))
+        with open(MVT_CONFIG_PATH, "w") as config_file:
+            config_file.write(yaml.dump(model_serializable, default_flow_style=False))
+
+    @classmethod
+    def initialise(cls) -> "MVTSettings":
+        """
+        Initialise the settings file.
+
+        We first initialise the settings (without env variable) and then persist
+        them to file. This way we can update the config file with the default values.
+
+        Afterwards we load the settings again, this time including the env variables.
+        """
+        # Set invalid env prefix to avoid loading env variables.
+        settings = MVTSettings(load_env=False)
+        settings.save_settings()
+
+        # Load the settings again with any ENV variables.
+        settings = MVTSettings(load_env=True)
+        return settings
+
+
+settings = MVTSettings.initialise()