refactor: slightly clean up config parsing

nyacme/config.py

@@ -1,7 +1,7 @@
 import logging
 import os
 import sys
-from typing import Optional
+from typing import Any, Optional
 
 import tomllib
 
@@ -33,6 +33,20 @@ class Config:
         return self.secrets[handler]
 
 
+def config_parse_dict(raw_conf: dict[str, Any], key: str) -> dict[str, str]:
+    if key not in raw_conf:
+        log.error(f'missing "{key}" in config')
+        sys.exit(1)
+
+    for k, v in raw_conf[key].items():
+        assert isinstance(k, str), f'"{k}" is not a string'
+        assert isinstance(v, str), f'"{k}" value "{v}" is not a string'
+
+    result: dict[str, str] = raw_conf[key]
+
+    return result
+
+
 def read_config(path: Optional[str]) -> Config:
     if not path:
         # should be here only when running from hook
@@ -47,25 +61,8 @@ def read_config(path: Optional[str]) -> Config:
 
     c = Config()
 
-    if 'domains' not in raw_conf:
+    c.domains = config_parse_dict(raw_conf, 'domains')
-        log.error('missing "domains"')
+    c.secrets = config_parse_dict(raw_conf, 'secrets')
-        sys.exit(1)
-
-    for k, v in raw_conf['domains'].items():
-        assert isinstance(k, str), f'domain "{k}" is not a string'
-        assert isinstance(v, str), f'domain "{k}" handler {v} is not a string'
-
-    c.domains = raw_conf['domains']
-
-    if 'secrets' not in raw_conf:
-        log.error('missing "secrets"')
-        sys.exit(1)
-
-    for k, v in raw_conf['secrets'].items():
-        assert isinstance(k, str), f'secret key "{k}" is not a string'
-        assert isinstance(v, str), f'secret "{k}" value {v} is not a string'
-
-    c.secrets = raw_conf['secrets']
 
     post_acquire = []
     if 'post_acquire' in raw_conf: