template-engine-copier skill: initial import

Copier + Jinja template-repository design skill: reference architecture,
implementation workflow, validation checklist, and a full worked example
template (questionnaire, extensions, resolvers, wrapper-first .scripts).

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

example/.copier/copier.yaml

@@ -0,0 +1,20 @@
+---
+_template_suffix: ".jinja"
+
+_exclude:
+  - ".git"
+  - ".copier"
+  - ".scripts"
+  - ".venv"
+  - "Taskfile.yml"
+  - "pyproject.toml"
+  - "copier-answers-new.yml"
+
+_jinja_extensions:
+  - copier_templates_extensions.TemplateExtensionLoader
+  - .copier/extensions/context_hook_extension/hook.py:ContextHookExtension
+  - .copier/extensions/resolvers/resolve_safe_identifier.py:SafeIdentifierExtension
+
+_answers_file: copier-answers.yml
+
+!include .copier/questionnaire/*.yml

example/.copier/extensions/context_hook_extension/hook.py

@@ -0,0 +1,72 @@
+import os
+import shutil
+
+from copier_templates_extensions import ContextHook
+
+
+class ContextHookExtension(ContextHook):
+    update = False
+
+    def hook(self, context):
+        _ensure_flat_variables(context)
+        _ensure_resources_instances(context)
+        return context
+
+
+def _ensure_flat_variables(context):
+    if 'flat' not in context or not isinstance(context.get('flat'), dict):
+        context['flat'] = {}
+
+    metadata = context.get('template_metadata', {}) if isinstance(context, dict) else {}
+    features = context.get('features', {}) if isinstance(context, dict) else {}
+    modules = features.get('modules', {}) if isinstance(features, dict) else {}
+
+    domain_name = metadata.get('domain', '') if isinstance(metadata, dict) else ''
+    project_name = metadata.get('project', '') if isinstance(metadata, dict) else ''
+
+    context['flat']['domain_name'] = domain_name
+    context['flat']['project_name'] = project_name
+
+    instances = modules.get('instances', []) if isinstance(modules, dict) else []
+    is_enabled = bool(modules.get('is_enabled', False)) if isinstance(modules, dict) else False
+
+    names = []
+    for instance in instances if isinstance(instances, list) else []:
+        if isinstance(instance, dict) and instance.get('name'):
+            names.append(f"{domain_name}-{project_name}-{instance['name']}")
+
+    context['flat']['modules_is_enabled'] = is_enabled
+    context['flat']['module_instance_names'] = names
+
+
+def _ensure_resources_instances(context):
+    """Expand folders containing [INDEX] into concrete per-instance directories."""
+    base_path = './src'
+    if not os.path.exists(base_path):
+        return
+
+    targets = []
+    for root, dirs, _ in os.walk(base_path):
+        for d in dirs:
+            if '[INDEX]' in d:
+                targets.append(os.path.join(root, d))
+
+    for path in targets:
+        parent = os.path.dirname(path)
+        instances = context.get('flat', {}).get('module_instance_names', [])
+        for idx, name in enumerate(instances):
+            dst = os.path.join(parent, name)
+            if os.path.exists(dst):
+                continue
+            os.makedirs(dst, exist_ok=True)
+            for fn in os.listdir(path):
+                src_file = os.path.join(path, fn)
+                if not os.path.isfile(src_file):
+                    continue
+                with open(src_file, 'r', encoding='utf-8') as f:
+                    content = f.read().replace('INDEX', str(idx))
+                with open(os.path.join(dst, fn), 'w', encoding='utf-8') as f:
+                    f.write(content)
+
+        if os.path.exists(path):
+            shutil.rmtree(path)

example/.copier/extensions/resolvers/resolve_safe_identifier.py

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+from jinja2.ext import Extension
+
+
+def resolve_safe_identifier(name: str) -> str:
+    return (
+        name
+        .replace("-", "_")
+        .replace("{", "")
+        .replace("}", "")
+        .replace(".", "_")
+    )
+
+
+class SafeIdentifierExtension(Extension):
+    def __init__(self, environment):
+        super().__init__(environment)
+        environment.globals["resolve_safe_identifier"] = resolve_safe_identifier

example/.copier/packages/utils_loggers/__init__.py

@@ -0,0 +1 @@
+from .loggers import info, warning, debug

example/.copier/packages/utils_loggers/loggers.py

@@ -0,0 +1,16 @@
+import logging
+
+
+logging.basicConfig(level=logging.INFO)
+
+
+def info(name, message, extra=None):
+    logging.getLogger(name).info(message)
+
+
+def warning(name, message, extra=None):
+    logging.getLogger(name).warning(message)
+
+
+def debug(name, message, extra=None):
+    logging.getLogger(name).debug(message)

example/.copier/questionnaire/0100-template.yml

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+template_metadata:
+  type: yaml
+  help: "Generic template metadata used by naming and rendering hooks"
+  default: |
+    domain: demo
+    project: sample-product
+
+features:
+  type: yaml
+  help: "Feature/module matrix for template rendering"
+  default: |
+    modules:
+      is_enabled: true
+      instances:
+        - name: users
+          version: 1.0.0
+        - name: billing
+          version: 1.0.0