no cache mode

Add no_cache config flag, defaulting to False. When no_cache=True, pypyr will bypass the internal caches entirely. pypyr will NOT retrieve anything from cache nor save anything to cache while no_cache=True. Setting this flag has no effect on items currently in cache, but any get() operation on a cache won't even look at these while the no_cache flag is True. Closes #317.
pypyr · Mar 13, 2023 · b3a0393 · b3a0393
1 parent b45488b
commit b3a0393
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Showing 6 changed files with 146 additions and 25 deletions.
diff --git a/pypyr/cache/backoffcache.py b/pypyr/cache/backoffcache.py
@@ -7,7 +7,7 @@
 import logging
 from pypyr.cache.cache import Cache
 import pypyr.moduleloader
-import pypyr.retries
+from pypyr.retries import builtin_backoffs
 
 logger = logging.getLogger(__name__)
 
@@ -18,13 +18,13 @@ class BackoffCache(Cache):
     def __init__(self):
         """Initialize the cache with the built-in back-off strategies."""
         super().__init__()
-        self._cache = pypyr.retries.builtin_backoffs.copy()
+        self._cache = builtin_backoffs.copy()
 
     def clear(self):
         """Clear the cache of all objects except built-in back-offs.."""
         with self._lock:
             # rather than iterating & selectively removing, just reset entirely
-            self._cache = pypyr.retries.builtin_backoffs.copy()
+            self._cache = builtin_backoffs.copy()
 
     def get_backoff(self, name):
         """Get cached backoff callable. Adds to cache if not exist.
@@ -62,13 +62,20 @@ def load_backoff_callable(name):
     module_name, dot, attr_name = name.rpartition('.')
     if not dot:
         # just a bare name, no dot, means must be in globals.
-        # note that built-in backoffs already in cache, so this will only run
-        # for bare names that aren't built-in back-offs.
-        raise ValueError(
-            f"Trying to find back-off strategy '{name}'. If this is a "
-            "built-in back-off strategy, are you sure you got the name right?"
-            "\nIf you're trying to load a custom callable, name should be in "
-            "format 'package.module.ClassName' or 'mod.ClassName'.")
+        backoff_callable = builtin_backoffs.get(name)
+
+        if backoff_callable:
+            logger.debug("found built-in backoff callable `%s`", name)
+            return backoff_callable
+        else:
+            # note that built-in backoffs already in cache, so this will only
+            # run for bare names that aren't built-in back-offs.
+            raise ValueError(
+                f"Trying to find back-off strategy '{name}'. If this is a "
+                "built-in back-off strategy, are you sure you got the name "
+                "right?\nIf you're trying to load a custom callable, name "
+                "should be in format 'package.module.ClassName' or "
+                "'mod.ClassName'.")
 
     backoff_module = pypyr.moduleloader.get_module(module_name)
     logger.debug("retry backoff strategy module loaded: %s", backoff_module)

diff --git a/pypyr/cache/cache.py b/pypyr/cache/cache.py
@@ -2,6 +2,8 @@
 import logging
 import threading
 
+from pypyr.config import config
+
 # use pypyr logger to ensure loglevel is set correctly
 logger = logging.getLogger(__name__)
 
@@ -34,19 +36,27 @@ def get(self, key, creator):
         Be warned that get happens under the context of a Lock. . . so if
         creator takes a long time you might well be blocking.
 
+        If config no_cache is True, bypasses cache entirely - will call
+        creator each time and also not save the result to cache.
+
         Args:
             key: key (unique id) of cached item
             creator: callable that will create cached object if key not found
 
         Returns:
             Cached item at key or the result of creator()
         """
+        if config.no_cache:
+            logger.debug("no cache mode enabled. creating `%s` sans cache",
+                         key)
+            return creator()
+
         with self._lock:
             if key in self._cache:
-                logger.debug("%s loading from cache", key)
+                logger.debug("`%s` loading from cache", key)
                 obj = self._cache[key]
             else:
-                logger.debug("%s not found in cache. . . creating", key)
+                logger.debug("`%s` not found in cache. . . creating", key)
                 obj = creator()
                 self._cache[key] = obj
 

diff --git a/pypyr/config.py b/pypyr/config.py
@@ -64,6 +64,7 @@ class Config():
             Set by init().
         vars: dict. User provided variables to write into the pypyr context.
             Set by init().
+        no_cache: bool. Default False. Bypass all pypyr caches entirely.
         platform_paths: pypyr.platform.PlatformPaths: O/S specific paths to
             config files & data dirs. Set by init().
         pyproject_toml: dict. The pyproject.toml file as a dict in a full.
@@ -90,6 +91,8 @@ class Config():
         'default_group',
         'default_success_group',
         'default_failure_group',
+        # flags
+        'no_cache',
         # functional
         'shortcuts',
         'vars'}
@@ -125,6 +128,10 @@ def __init__(self) -> None:
         self.default_success_group = 'on_success'
         self.default_failure_group = 'on_failure'
 
+        # flags
+        self.no_cache: bool = cast_str_to_bool(os.getenv('PYPYR_NO_CACHE',
+                                                         '0'))
+
         # functional
         self.shortcuts: dict = {}
         self.vars: dict = {}

diff --git a/tests/unit/pypyr/cache/backoffcache_test.py b/tests/unit/pypyr/cache/backoffcache_test.py
@@ -73,6 +73,30 @@ def test_get_backoff_builtin():
     assert callable_ref(789) == 123
     assert callable_ref(999) == 123
 
+
+@pytest.fixture
+def no_cache(monkeypatch):
+    """Set no cache."""
+    monkeypatch.setattr('pypyr.cache.cache.config.no_cache', True)
+
+
+def test_get_backoff_builtin_no_cache(no_cache):
+    """Load built-in backoff callable when no_cache true."""
+    backoff_cache = backoffcache.BackoffCache()
+    f = backoff_cache.get_backoff('fixed')
+
+    callable_ref = f(sleep=123, max_sleep=456)
+    assert callable_ref(789) == 123
+    assert callable_ref(999) == 123
+
+    f2 = backoff_cache.get_backoff('fixed')
+    callable_ref = f2(sleep=789, max_sleep=1000)
+    assert callable_ref(111) == 789
+
+    # didn't add anything to cache even when calling same built-in twice,
+    # bypassing it entirely
+    assert backoff_cache._cache == pypyr.retries.builtin_backoffs
+
 # endregion BackoffCache: get_backoff
 
 # region BackoffCache: clear

diff --git a/tests/unit/pypyr/cache/cache_test.py b/tests/unit/pypyr/cache/cache_test.py
@@ -1,10 +1,19 @@
 """cache.py unit tests."""
 import logging
 from unittest.mock import call, MagicMock
+
+import pytest
+
 from pypyr.cache.cache import Cache
 from tests.common.utils import patch_logger
 
 
+@pytest.fixture
+def no_cache(monkeypatch):
+    """Set no cache."""
+    monkeypatch.setattr('pypyr.cache.cache.config.no_cache', True)
+
+
 def test_cache_get_miss():
     """Cache get should execute creator."""
     cache = Cache()
@@ -17,7 +26,7 @@ def test_cache_get_miss():
     assert obj == "created obj"
     creator_mock.assert_called_once_with("1")
     mock_logger_debug.assert_called_once_with(
-        "one not found in cache. . . creating")
+        "`one` not found in cache. . . creating")
 
 
 def test_cache_get_hit():
@@ -36,15 +45,47 @@ def test_cache_get_hit():
     assert obj3 == "created obj1"
 
     creator_mock.assert_called_once_with("1")
+
     assert mock_logger_debug.mock_calls == [
-        call("one not found in cache. . . creating"),
-        call("one loading from cache"),
-        call("one loading from cache")]
+        call("`one` not found in cache. . . creating"),
+        call("`one` loading from cache"),
+        call("`one` loading from cache")]
 
     obj4 = creator_mock("4")
     assert obj4 == "created obj2"
 
 
+def test_cache_get_hit_no_cache(no_cache):
+    """Cache get with no_cache set should run creator each time."""
+    cache = Cache()
+    creator_mock = MagicMock()
+    creator_mock.side_effect = ["created obj1", "created obj2", "created obj3",
+                                "created obj4"]
+
+    with patch_logger('pypyr.cache', logging.DEBUG) as mock_logger_debug:
+        obj1 = cache.get('one', lambda: creator_mock("1"))
+        obj2 = cache.get('one', lambda: creator_mock("2"))
+        obj3 = cache.get('one', lambda: creator_mock("3"))
+
+    assert obj1 == "created obj1"
+    assert obj2 == "created obj2"
+    assert obj3 == "created obj3"
+
+    assert creator_mock.mock_calls == [
+        call('1'),
+        call('2'),
+        call('3')
+    ]
+
+    assert mock_logger_debug.mock_calls == [
+        call("no cache mode enabled. creating `one` sans cache"),
+        call("no cache mode enabled. creating `one` sans cache"),
+        call("no cache mode enabled. creating `one` sans cache")]
+
+    obj4 = creator_mock("4")
+    assert obj4 == "created obj4"
+
+
 def test_cache_multiple_items_get_hit_closures():
     """Cache with multiple items work."""
     cache = Cache()
@@ -66,10 +107,10 @@ def inner():
     assert obj4 == 5
 
     assert mock_logger_debug.mock_calls == [
-        call("one not found in cache. . . creating"),
-        call("two not found in cache. . . creating"),
-        call("three not found in cache. . . creating"),
-        call("one loading from cache")]
+        call("`one` not found in cache. . . creating"),
+        call("`two` not found in cache. . . creating"),
+        call("`three` not found in cache. . . creating"),
+        call("`one` loading from cache")]
 
 
 def test_cache_clear():
@@ -93,9 +134,9 @@ def inner():
     assert obj3 == 5
 
     assert mock_logger_debug.mock_calls == [
-        call("one not found in cache. . . creating"),
-        call("two not found in cache. . . creating"),
-        call("one loading from cache")]
+        call("`one` not found in cache. . . creating"),
+        call("`two` not found in cache. . . creating"),
+        call("`one` loading from cache")]
 
     obj1 = cache.get('one', closure(2, 3))
     obj2 = cache.get('two', closure(4, 5))

diff --git a/tests/unit/pypyr/config_test.py b/tests/unit/pypyr/config_test.py
@@ -24,6 +24,7 @@ def no_envs(monkeypatch):
     monkeypatch.delenv('PYPYR_SKIP_INIT', raising=False)
     monkeypatch.delenv('PYPYR_CONFIG_GLOBAL', raising=False)
     monkeypatch.delenv('PYPYR_CONFIG_LOCAL', raising=False)
+    monkeypatch.delenv('PYPYR_NO_CACHE', raising=False)
 
 # region default initialization
 
@@ -41,6 +42,8 @@ def test_config_defaults(no_envs):
     assert config.pyproject_toml is None
     assert config.skip_init is False
 
+    assert config.no_cache is False
+
     assert config.vars == {}
     assert config.shortcuts == {}
 
@@ -67,8 +70,31 @@ def test_config_with_encoding(monkeypatch, no_envs):
     monkeypatch.setenv('PYPYR_ENCODING', 'arb')
     monkeypatch.setenv('PYPYR_CMD_ENCODING', 'arb2')
     config = Config()
-    config.default_encoding == 'arb'
-    config.default_cmd_encoding == 'arb2'
+    assert config.default_encoding == 'arb'
+    assert config.default_cmd_encoding == 'arb2'
+
+
+def test_config_with_no_cache(monkeypatch, no_envs):
+    """Set no cache via env variable."""
+    monkeypatch.setenv('PYPYR_NO_CACHE', '1')
+    config = Config()
+    assert config.no_cache is True
+
+    monkeypatch.setenv('PYPYR_NO_CACHE', 'TRUE')
+    config = Config()
+    assert config.no_cache is True
+
+    monkeypatch.setenv('PYPYR_NO_CACHE', 'true')
+    config = Config()
+    assert config.no_cache is True
+
+    monkeypatch.setenv('PYPYR_NO_CACHE', '0')
+    config = Config()
+    assert config.no_cache is False
+
+    monkeypatch.setenv('PYPYR_NO_CACHE', 'fAlse')
+    config = Config()
+    assert config.no_cache is False
 
 
 def test_config_platforms(monkeypatch):
@@ -737,6 +763,7 @@ def test_config_default_str(no_envs):
 log_date_format: '%Y-%m-%d %H:%M:%S'
 log_detail_format: '%(asctime)s %(levelname)s:%(name)s:%(funcName)s: %(message)s'
 log_notify_format: '%(message)s'
+no_cache: false
 pipelines_subdir: pipelines
 shortcuts: {{}}
 vars: {{}}
@@ -765,6 +792,7 @@ def test_config_all_str(mock_get_platform, no_envs):
                    b'[tool.pypyr]\n'
                    b'pipelines_subdir = "arb4"\n'
                    b'default_success_group = "dsg"\n'
+                   b'no_cache = true\n'
                    b'[tool.pypyr.vars]\n'
                    b'a = "e"\n'
                    b'f4 = 4'))
@@ -802,6 +830,8 @@ def test_config_all_str(mock_get_platform, no_envs):
 
     assert config.platform_paths == fake_pp
 
+    assert config.no_cache is True
+
     mock_get_platform.assert_called_once_with('pypyr', 'config.yaml')
 
     assert mock_files.mock_calls == [
@@ -825,6 +855,7 @@ def test_config_all_str(mock_get_platform, no_envs):
 log_date_format: '%Y-%m-%d %H:%M:%S'
 log_detail_format: '%(asctime)s %(levelname)s:%(name)s:%(funcName)s: %(message)s'
 log_notify_format: '%(message)s'
+no_cache: true
 pipelines_subdir: arb5
 shortcuts:
   s1: one
@@ -858,6 +889,7 @@ def test_config_all_str(mock_get_platform, no_envs):
     pypyr:
       pipelines_subdir: arb4
       default_success_group: dsg
+      no_cache: true
       vars:
         a: e
         f4: 4