Turn talos patches into templates and resolve them

tools/merge

@@ -8,9 +8,29 @@ import pathlib
 
 import requests
 import yaml
+from jinja2 import Environment, FileSystemLoader, StrictUndefined, Template
 
 NODES = pathlib.Path("nodes")
 SCHEMATICS = pathlib.Path("schematics")
+PATCHES = Environment(loader=FileSystemLoader("patches"), undefined=StrictUndefined)
+TEMPLATES = Environment(loader=FileSystemLoader("templates"), undefined=StrictUndefined)
+
+
+def node_encoder(node: dict):
+    class Inner(json.JSONEncoder):
+        def default(self, o):
+            if isinstance(o, Template):
+                try:
+                    rendered = o.render(node)
+                except Exception as e:
+                    e.add_note(f"While rendering for: {node['hostname']}")
+                    raise e
+                # Parse the rendered yaml and convert it to a json patch
+                return json.dumps(yaml.safe_load(rendered))
+
+            return super().default(o)
+
+    return Inner
 
 
 @functools.cache
@@ -24,18 +44,28 @@ def get_schematic_id(schematic: str):
 
 def schematic_constructor(loader: yaml.SafeLoader, node: yaml.nodes.ScalarNode):
     """Load specified schematic file and get the assocatied schematic id"""
-    filename = loader.construct_scalar(node)
+    schematic_name = loader.construct_yaml_str(node)
     try:
-        schematic = SCHEMATICS.joinpath(filename).with_suffix(".yaml").read_text()
+        schematic = SCHEMATICS.joinpath(schematic_name).with_suffix(".yaml").read_text()
         return get_schematic_id(schematic)
     except Exception:
         raise yaml.MarkedYAMLError("Failed to load schematic", node.start_mark)
 
 
+def patch_constructor(loader: yaml.SafeLoader, node: yaml.nodes.ScalarNode):
+    patch_name = loader.construct_scalar(node)
+    try:
+        template = PATCHES.get_template(f"{patch_name}.yaml")
+        return template
+    except Exception:
+        raise yaml.MarkedYAMLError("Failed to load patch", node.start_mark)
+
+
 def get_loader():
     """Add special constructors to yaml loader"""
     loader = yaml.SafeLoader
     loader.add_constructor("!schematic", schematic_constructor)
+    loader.add_constructor("!patch", patch_constructor)
 
     return loader
 
@@ -65,7 +95,7 @@ def walk_files(root: pathlib.Path):
 
 
 def main():
-    data = []
+    nodes = []
     for fullname in walk_files(NODES):
         filename = str(fullname.relative_to(NODES).parent) + "/" + fullname.stem
 
@@ -74,10 +104,15 @@ def main():
         yml_data = get_defaults(fullname.parent, NODES) | yml_data
         yml_data["hostname"] = fullname.stem
         yml_data["filename"] = filename
-        data.append(yml_data)
+        nodes.append(yml_data)
+
+    final_nodes = []
+    for node in nodes:
+        # Quick and dirty way to resolve all the templates using a custom encoder
+        final_nodes.append(json.loads(json.dumps(node, cls=node_encoder(node))))
 
     # Dump everything to json
-    print(json.dumps(data, indent=4))
+    print(json.dumps(final_nodes, indent=4))
 
 
 if __name__ == "__main__":