Do not call IPlugin.prepare() for updaters when running renew (#6167)

interfaces.GenericUpdater and new enhancement interface updater functions get run on every invocation of Certbot with "renew" verb for every lineage. This causes performance problems for users with large configurations, because of plugin plumbing and preparsing happening in prepare() method of installer plugins. This PR moves the responsibility to call prepare() to the plugin (possibly) implementing a new style enhancement interface.

Fixes: #6153

* Do not call IPlugin.prepare() for updaters when running renew

* Check prepare called in tests

* Refine pydoc and make the function name more informative

* Verify the plugin type

certbot-apache/certbot_apache/configurator.py

@@ -165,6 +165,7 @@ class ApacheConfigurator(augeas_configurator.AugeasConfigurator):
         self._autohsts = {}  # type: Dict[str, Dict[str, Union[int, float]]]
 
         # These will be set in the prepare function
+        self._prepared = False
         self.parser = None
         self.version = version
         self.vhosts = None
@@ -249,6 +250,7 @@ class ApacheConfigurator(augeas_configurator.AugeasConfigurator):
             logger.debug("Encountered error:", exc_info=True)
             raise errors.PluginError(
                 "Unable to lock %s", self.conf("server-root"))
+        self._prepared = True
 
     def _check_aug_version(self):
         """ Checks that we have recent enough version of libaugeas.
@@ -2394,6 +2396,9 @@ class ApacheConfigurator(augeas_configurator.AugeasConfigurator):
                 continue
             nextstep = config["laststep"] + 1
             if nextstep < len(constants.AUTOHSTS_STEPS):
+                # If installer hasn't been prepared yet, do it now
+                if not self._prepared:
+                    self.prepare()
                 # Have not reached the max value yet
                 try:
                     vhost = self.find_vhost_by_id(id_str)

certbot-apache/certbot_apache/tests/autohsts_test.py

@@ -55,7 +55,9 @@ class AutoHSTSTest(util.ApacheTest):
 
     @mock.patch("certbot_apache.constants.AUTOHSTS_FREQ", 0)
     @mock.patch("certbot_apache.configurator.ApacheConfigurator.restart")
-    def test_autohsts_increase(self, _mock_restart):
+    @mock.patch("certbot_apache.configurator.ApacheConfigurator.prepare")
+    def test_autohsts_increase(self, mock_prepare, _mock_restart):
+        self.config._prepared = False
         maxage = "\"max-age={0}\""
         initial_val = maxage.format(constants.AUTOHSTS_STEPS[0])
         inc_val = maxage.format(constants.AUTOHSTS_STEPS[1])
@@ -69,6 +71,7 @@ class AutoHSTSTest(util.ApacheTest):
         # Verify increased value
         self.assertEquals(self.get_autohsts_value(self.vh_truth[7].path),
                           inc_val)
+        self.assertTrue(mock_prepare.called)
 
     @mock.patch("certbot_apache.configurator.ApacheConfigurator.restart")
     @mock.patch("certbot_apache.configurator.ApacheConfigurator._autohsts_increase")