Clarify env var lietime

Author: p1c2u

README.rst

@@ -98,6 +98,8 @@ The ``validate`` helper keeps an internal compiled-validator cache. You can
 control cache size using the
 ``OPENAPI_SCHEMA_VALIDATOR_COMPILED_VALIDATOR_CACHE_MAX_SIZE`` environment variable
 (default: ``128``).
+The value is loaded once at first use and reused for the lifetime of the
+process.
 
 To validate an OpenAPI schema:
 

docs/index.rst

@@ -91,7 +91,7 @@ Environment variables:
 
 * ``OPENAPI_SCHEMA_VALIDATOR_COMPILED_VALIDATOR_CACHE_MAX_SIZE``
   Maximum number of compiled validators kept by the ``validate`` shortcut
-  cache. Default: ``128``.
+  cache. Default: ``128``. Loaded once at first use.
 
 See :doc:`validation` for runtime behavior details.
 

docs/validation.rst

@@ -42,6 +42,7 @@ skip schema checking.
 The shortcut keeps an internal compiled-validator cache.
 Use ``OPENAPI_SCHEMA_VALIDATOR_COMPILED_VALIDATOR_CACHE_MAX_SIZE`` to control cache
 capacity (default: ``128``).
+The setting is read once at first use and then cached for the process lifetime.
 
 To validate an OpenAPI schema:
 

tests/unit/test_settings.py

@@ -0,0 +1,24 @@
+from openapi_schema_validator.settings import get_settings
+from openapi_schema_validator.settings import reset_settings_cache
+
+
+def test_compiled_validator_cache_size_env_is_cached(monkeypatch):
+    monkeypatch.setenv(
+        "OPENAPI_SCHEMA_VALIDATOR_COMPILED_VALIDATOR_CACHE_MAX_SIZE",
+        "11",
+    )
+    reset_settings_cache()
+
+    first = get_settings()
+    assert first.compiled_validator_cache_max_size == 11
+
+    monkeypatch.setenv(
+        "OPENAPI_SCHEMA_VALIDATOR_COMPILED_VALIDATOR_CACHE_MAX_SIZE",
+        "3",
+    )
+    second = get_settings()
+    assert second.compiled_validator_cache_max_size == 11
+
+    reset_settings_cache()
+    third = get_settings()
+    assert third.compiled_validator_cache_max_size == 3