Add `config render` command

This is going to be useful for using custom themes with user-defined
variables.

CHANGELOG.md

@@ -2,6 +2,10 @@
 
 Note: Breaking changes between versions are indicated by "💥".
 
+## Unreleased
+
+- [Feature] Add `config render` command
+
 ## 3.11.0 (2020-01-14)
 
 - [Feature] Add support for simple, YAML-based plugins

tests/test_env.py

@@ -25,6 +25,14 @@ class EnvTests(unittest.TestCase):
         self.assertIn(template_name, renderer.environment.loader.list_templates())
         self.assertNotIn(template_name, templates)
 
+    def test_is_binary_file(self):
+        self.assertTrue(env.is_binary_file("/home/somefile.ico"))
+
+    def test_find_path(self):
+        renderer = env.Renderer({}, [env.TEMPLATES_ROOT])
+        path = renderer.find_path("local/docker-compose.yml")
+        self.assertTrue(os.path.exists(path))
+
     def test_pathjoin(self):
         self.assertEqual(
             "/tmp/env/target/dummy", env.pathjoin("/tmp", "target", "dummy")

tutor/commands/config.py

@@ -59,6 +59,28 @@ def save(context, interactive, set_, unset):
     env.save(context.root, config)
 
 
+@click.command(help="Render a template folder with eventual extra configuration files")
+@click.option(
+    "-x",
+    "--extra-config",
+    "extra_configs",
+    multiple=True,
+    type=click.Path(exists=True, resolve_path=True, dir_okay=False),
+    help="Load extra configuration file (can be used multiple times)",
+)
+@click.argument("src", type=click.Path(exists=True, resolve_path=True))
+@click.argument("dst")
+@click.pass_obj
+def render(context, extra_configs, src, dst):
+    config = tutor_config.load(context.root)
+    for extra_config in extra_configs:
+        tutor_config.merge(config, tutor_config.load_file(extra_config), force=True)
+
+    renderer = env.Renderer(config, [src])
+    renderer.render_all_to(dst)
+    fmt.echo_info("Templates rendered to {}".format(dst))
+
+
 @click.command(help="Print the project root")
 @click.pass_obj
 def printroot(context):
@@ -77,5 +99,6 @@ def printvalue(context, key):
 
 
 config_command.add_command(save)
+config_command.add_command(render)
 config_command.add_command(printroot)
 config_command.add_command(printvalue)

tutor/config.py

@@ -56,6 +56,11 @@ def load_defaults():
     return serialize.load(env.read("config.yml"))
 
 
+def load_file(path):
+    with open(path) as f:
+        return serialize.load(f.read())
+
+
 def load_current(root, defaults):
     """
     Load the configuration currently stored on disk.

tutor/env.py

@@ -14,6 +14,7 @@ from .__about__ import __version__
 
 TEMPLATES_ROOT = pkg_resources.resource_filename("tutor", "templates")
 VERSION_FILENAME = "version"
+BIN_FILE_EXTENSIONS = [".ico", ".ttf", ".png", ".jpg"]
 
 
 class Renderer:
@@ -38,6 +39,7 @@ class Renderer:
 
     def __init__(self, config, template_roots):
         self.config = deepcopy(config)
+        self.template_roots = template_roots
 
         # Create environment
         environment = jinja2.Environment(
@@ -68,6 +70,13 @@ class Renderer:
         """
         yield from self.iter_templates_in(subdir + "/")
 
+    def find_path(self, path):
+        for templates_root in self.template_roots:
+            full_path = os.path.join(templates_root, path)
+            if os.path.exists(full_path):
+                return full_path
+        raise ValueError("Template path does not exist")
+
     def patch(self, name, separator="\n", suffix=""):
         """
         Render calls to {{ patch("...") }} in environment templates from plugin patches.
@@ -93,11 +102,17 @@ class Renderer:
         return self.__render(template)
 
     def render_file(self, path):
+        if is_binary_file(path):
+            # Don't try to render binary files
+            with open(self.find_path(path), "rb") as f:
+                return f.read()
+
         try:
             template = self.environment.get_template(path)
         except Exception:
             fmt.echo_error("Error loading template " + path)
             raise
+
         try:
             return self.__render(template)
         except (jinja2.exceptions.TemplateError, exceptions.TutorError):
@@ -107,6 +122,12 @@ class Renderer:
             fmt.echo_error("Unknown error rendering template " + path)
             raise
 
+    def render_all_to(self, root):
+        for template in self.iter_templates_in():
+            rendered = self.render_file(template)
+            dst = os.path.join(root, template)
+            write_to(rendered, dst)
+
     def __render(self, template):
         try:
             return template.render(**self.config)
@@ -165,8 +186,14 @@ def save_all_from(prefix, root, config):
 
 
 def write_to(content, path):
+    """
+    Content can be either str or bytes.
+    """
+    open_mode = "w"
+    if isinstance(content, bytes):
+        open_mode += "b"
     utils.ensure_file_directory_exists(path)
-    with open(path, "w") as of:
+    with open(path, open_mode) as of:
         of.write(content)
 
 
@@ -262,10 +289,15 @@ def is_part_of_env(path):
     is_excluded = False
     is_excluded = is_excluded or basename.startswith(".") or basename.endswith(".pyc")
     is_excluded = is_excluded or basename == "__pycache__"
-    is_excluded = is_excluded or "partials" in parts
+    is_excluded = is_excluded or "partials" in parts or ".git" in parts
     return not is_excluded
 
 
+def is_binary_file(path):
+    ext = os.path.splitext(path)[1]
+    return ext in BIN_FILE_EXTENSIONS
+
+
 def template_path(*path, templates_root=TEMPLATES_ROOT):
     """
     Return the template file's absolute path.