Merge pull request #471 from flyingcircusio/warn-if-has-update-but-no…

…-verify

Add warning: If component has update() but no verify()

src/batou/__init__.py

@@ -521,6 +521,43 @@ def report(self):
         output.tabular("Root", self.root_name, red=True)
 
 
+class ComponentWithUpdateWithoutVerify(ConfigurationError):
+    """Some components have an update method but no verify method."""
+
+    sort_key = (5, "without_verify")
+
+    @classmethod
+    def from_context(cls, components, roots):
+        self = cls()
+        self.components = []
+        for component in components:
+            self.components.append(repr(component.__class__.__name__))
+        self.roots = []
+        for root in roots:
+            self.roots.append(root.name)
+        return self
+
+    def __str__(self):
+        out_str = "Some components have an update method but no verify method:"
+        for idx, component in enumerate(self.components):
+            out_str += f"\n    {component}"
+            out_str += f"\nRoot: {self.roots[idx]}"
+        out_str += f"\nThe update() method may not be called by batou if the verify() method is missing."
+        return out_str
+
+    def report(self):
+        output.error(
+            f"Some components have an update method but no verify method:"
+        )
+        for component in self.components:
+            output.line(f"    {component}", red=True)
+        output.tabular("Root", self.root_name, red=True)
+        output.line(
+            f"The update() method may not be called by batou if the verify() method is missing.",
+            red=True,
+        )
+
+
 class UnsatisfiedResources(ConfigurationError):
     """Some required resources were never provided."""
 

src/batou/environment.py

@@ -15,6 +15,7 @@
 import batou.vfs
 from batou import (
     ComponentLoadingError,
+    ComponentWithUpdateWithoutVerify,
     ConfigurationError,
     CycleErrorDetected,
     DuplicateHostError,
@@ -492,6 +493,7 @@ def configure(self):
 
         while working_set:
             exceptions = []
+            components_without_verify = []
             previous_working_sets.append(working_set.copy())
             retry = set()
             self.resources.dirty_dependencies.clear()
@@ -518,6 +520,8 @@ def configure(self):
                         )
                     )
                 else:
+                    # warnings: does not fail the deployment
+                    # 1. unprepared component warning
                     unprepared_components = []
                     for component in Component._instances:
                         if not component._prepared:
@@ -531,6 +535,21 @@ def configure(self):
                         )
                         # exceptions.append(unused_exception)
                         output.warn(str(unused_exception))
+
+                    # 2. a component has .update() but no .verify()
+                    def has_original_update_method(component):
+                        return type(component).update == Component.update
+
+                    def has_original_verify_method(component):
+                        return type(component).verify == Component.verify
+
+                    for component in Component._instances:
+                        if (
+                            not has_original_update_method(component)
+                            and has_original_verify_method(component)
+                            and (component not in components_without_verify)
+                        ):
+                            components_without_verify.append((component, root))
                     # configured this component successfully
                     # we won't have to retry it later
                     continue
@@ -573,6 +592,15 @@ def configure(self):
 
             working_set = retry
 
+        # warn if a component has .update() but no .verify()
+        if components_without_verify:
+            component_without_verify_exception = (
+                ComponentWithUpdateWithoutVerify.from_context(
+                    components_without_verify, root
+                )
+            )
+            output.warn(str(component_without_verify_exception))
+
         # We managed to converge on a working set. However, some resource were
         # provided but never used. We're rather picky here and report this as
         # an error.