secrets: initial implmentation

Add support for an external "secrets" file that may contain
usernames, passwords, and tokens.  This file may be in
"ini" or "json" format.

Signed-off-by:  Eric Callahan <arksine.code@gmail.com>

moonraker/components/secrets.py

@@ -0,0 +1,85 @@
+# Support for password/token secrets
+#
+# Copyright (C) 2021  Eric Callahan <arksine.code@gmail.com>
+#
+# This file may be distributed under the terms of the GNU GPLv3 license.
+from __future__ import annotations
+import pathlib
+import logging
+import configparser
+import json
+from typing import (
+    TYPE_CHECKING,
+    Dict,
+    Optional,
+    Any
+)
+if TYPE_CHECKING:
+    from confighelper import ConfigHelper
+
+class Secrets:
+    def __init__(self, config: ConfigHelper) -> None:
+        server = config.get_server()
+        self.secrets_file: Optional[pathlib.Path] = None
+        path: Optional[str] = config.get('secrets_path', None)
+        self.type = "invalid"
+        self.values: Dict[str, Any] = {}
+        if path is not None:
+            self.secrets_file = pathlib.Path(path).expanduser().resolve()
+            if not self.secrets_file.is_file():
+                server.add_warning(
+                    "[secrets]: option 'secrets_path', file does not exist: "
+                    f"'{self.secrets_file}'")
+                return
+            data = self.secrets_file.read_text()
+            vals = self._parse_json(data)
+            if vals is not None:
+                if not isinstance(vals, dict):
+                    server.add_warning(
+                        f"[secrets]: option 'secrets_path', top level item in"
+                        f" json file '{self.secrets_file}' must be an Object.")
+                    return
+                self.values = vals
+                self.type = "json"
+            else:
+                vals = self._parse_ini(data)
+                if vals is None:
+                    server.add_warning(
+                        "[secrets]: option 'secrets_path', invalid file "
+                        f"format, must be json or ini: '{self.secrets_file}'")
+                    return
+                self.values = vals
+                self.type = "ini"
+            logging.debug(f"[secrets]: Loaded {self.type} file: "
+                          f"{self.secrets_file}")
+        else:
+            logging.debug(
+                "[secrets]: Option `secrets_path` not supplied")
+
+    def _parse_ini(self, data: str) -> Optional[Dict[str, Any]]:
+        try:
+            cfg = configparser.ConfigParser(interpolation=None)
+            cfg.read_string(data)
+            result = dict(cfg)
+            return result
+        except Exception:
+            return None
+
+    def _parse_json(self, data: str) -> Optional[Dict[str, Any]]:
+        try:
+            return json.loads(data)
+        except json.JSONDecodeError:
+            return None
+
+    def get_type(self) -> str:
+        return self.type
+
+    def __getitem__(self, key: str) -> Any:
+        return self.values[key]
+
+    def get(self, key: str, default: Any = None) -> Any:
+        return self.values.get(key, default)
+
+
+def load_component(config: ConfigHelper) -> Secrets:
+    return Secrets(config)