Add variable batou_generated_header to global template rendering co…

…ntext

CHANGES.md

@@ -6,6 +6,9 @@
 
 - Fix unsatisfied resource message if a host-specific resource is not
   satisfied. (#463)
+- Adds variable `batou_generated_header` to global template rendering
+  context. This variable contains a comment block that signals that
+  the file content is generated by batou. (#356)
 
 
 ## 2.5.0b3 (2024-08-05)

src/batou/component.py

@@ -16,6 +16,10 @@
 from batou import DuplicateComponent, SilentConfigurationError, output
 from batou.utils import call_with_optional_args
 
+batou_generated_header = """\
+# File is generated by batou. Don't edit manually.
+"""
+
 
 def platform(name, component):
     """Class decorator to register a component class as a platform-component
@@ -945,6 +949,7 @@ def _template_args(self, component=None, **kw):
             host=component.host,
             environment=component.environment,
             component=component,
+            batou_generated_header=batou_generated_header,
         )
         args.update(kw)
         return args

src/batou/tests/test_component.py

@@ -417,6 +417,14 @@ def test_templates(root):
     assert root.component.template("sample") == ("Hello localhost\n")
 
 
+def test_template_batou_generated_header(root):
+    with open("sample", "w") as template:
+        template.write("Hello\n{{batou_generated_header}}")
+    assert root.component.template("sample") == (
+        "Hello\n# File is generated by batou. Don't edit manually.\n\n"
+    )
+
+
 def test_chdir_contextmanager_is_stackable():
     outer = os.getcwd()
     inner1 = os.path.join(os.path.dirname(__file__), "fixture")