feat(cli): allow ignoring template rendering errors (#3697)

renku/core/errors.py

@@ -485,11 +485,11 @@ class TemplateError(RenkuException):
 
 
 class InvalidTemplateError(TemplateError):
-    """Raised when using a non-valid template."""
+    """Raised when using an invalid template."""
 
 
 class TemplateMissingReferenceError(TemplateError):
-    """Raised when using a non-valid template."""
+    """Raised when a reference cannot be found in the template's repository."""
 
 
 class TemplateUpdateError(TemplateError):

renku/core/init.py

@@ -110,6 +110,7 @@ def init_project(
     input_parameters: Dict[str, str],
     custom_metadata: Optional[Dict[str, Any]],
     force: bool,
+    ignore_template_errors: bool,
     data_dir: Optional[Path],
     initial_branch: Optional[str],
     install_mergetool: bool,
@@ -129,6 +130,7 @@ def init_project(
         input_parameters: Template parameters.
         custom_metadata: Custom JSON-LD metadata for project.
         force: Whether to overwrite existing files and delete existing metadata.
+        ignore_template_errors: Create project anyway even if template rendering fails.
         data_dir: Where to store dataset data.
         initial_branch: Default git branch.
         install_mergetool(bool): Whether to set up the renku metadata mergetool in the created project.
@@ -181,7 +183,7 @@ def init_project(
     # TODO: Validate input_parameters to make sure they don't contain __\w+__ keys
     set_template_parameters(template=template, template_metadata=template_metadata, input_parameters=input_parameters)
 
-    rendered_template = template.render(metadata=template_metadata)
+    rendered_template = template.render(metadata=template_metadata, ignore_template_errors=ignore_template_errors)
     actions = get_file_actions(
         rendered_template=rendered_template, template_action=TemplateAction.INITIALIZE, interactive=False
     )

renku/domain_model/template.py

@@ -28,6 +28,7 @@
 
 from renku.core import errors
 from renku.core.constant import RENKU_HOME
+from renku.core.util import communication
 from renku.core.util.os import get_safe_relative_path, hash_file, hash_string
 from renku.core.util.util import to_string
 
@@ -343,16 +344,23 @@ def get_files(self) -> Generator[str, None, None]:
             if subpath.is_file():
                 yield str(subpath.relative_to(self.path))
 
-    def render(self, metadata: "TemplateMetadata") -> "RenderedTemplate":
+    def render(self, metadata: "TemplateMetadata", ignore_template_errors: bool = False) -> "RenderedTemplate":
         """Render template files in a new directory."""
         if self.path is None:
             raise ValueError("Template path not set")
 
         render_base = Path(tempfile.mkdtemp())
 
         for relative_path in self.get_files():
-            # NOTE: The path could contain template variables, we need to template it
-            rendered_relative_path = jinja2.Template(relative_path).render(metadata.metadata)
+            try:
+                # NOTE: The path could contain template variables, we need to template it
+                rendered_relative_path = jinja2.Template(relative_path).render(metadata.metadata)
+            except jinja2.TemplateError as e:
+                if ignore_template_errors:
+                    rendered_relative_path = relative_path
+                    communication.warn(f"Ignoring template error when rendering path '{relative_path}'")
+                else:
+                    raise errors.InvalidTemplateError(f"Cannot render template file path '{relative_path}': {e}")
 
             destination = render_base / rendered_relative_path
             destination.parent.mkdir(parents=True, exist_ok=True)
@@ -365,9 +373,20 @@ def render(self, metadata: "TemplateMetadata") -> "RenderedTemplate":
                 content_bytes = source.read_bytes()
                 destination.write_bytes(content_bytes)
             else:
-                template = jinja2.Template(content, keep_trailing_newline=True)
-                rendered_content = template.render(metadata.metadata)
-                destination.write_text(rendered_content)
+                try:
+                    rendered_content = jinja2.Template(content, keep_trailing_newline=True).render(metadata.metadata)
+                except jinja2.TemplateError as e:
+                    if ignore_template_errors:
+                        destination.write_text(content)
+                        communication.warn(
+                            f"Ignoring template rendering error when creating '{rendered_relative_path}'"
+                        )
+                    else:
+                        raise errors.InvalidTemplateError(
+                            f"Cannot render template file '{rendered_relative_path}': {e}"
+                        )
+                else:
+                    destination.write_text(rendered_content)
 
         return RenderedTemplate(path=render_base, template=self, metadata=metadata.metadata)
 
@@ -432,8 +451,8 @@ def from_dict(cls, name: str, value: Dict[str, Any]):
     @property
     def has_default(self) -> bool:
         """Return True if a default value is set."""
-        # NOTE: ``None`` cannot be used as the default value but it's ok since no variable type accepts it and it's not
-        # a valid value anyways
+        # NOTE: ``None`` cannot be used as the default value, but it's ok since no variable type accepts it, and it's
+        # not a valid value anyway
         return self.default is not None
 
     def validate(self, raise_errors: bool = True) -> List[str]:

renku/ui/cli/init.py

@@ -53,6 +53,10 @@
 source ``--template-source`` (both local path and remote url are supported) and
 the reference ``--template-ref`` (branch, tag or commit).
 
+If the template contains an error that prevents it from being rendered, you can
+ignore this error by passing ``--ignore-template-errors`` to the ``init``
+command.
+
 You can take inspiration from the
 `official Renku template repository
 <https://github.com/SwissDataScienceCenter/renku-project-template>`_
@@ -259,6 +263,7 @@ def resolve_data_directory(data_dir, path):
 @click.option("-l", "--list-templates", is_flag=True, help="List templates available in the template-source.")
 @click.option("-d", "--describe", is_flag=True, help="Show description for templates and parameters")
 @click.option("--force", is_flag=True, help="Override target path.")
+@click.option("--ignore-template-errors", is_flag=True, help="Ignore template rendering errors.")
 @click.option("--initial-branch", help="Initial git branch to create.")
 @option_external_storage_requested
 @click.pass_context
@@ -277,6 +282,7 @@ def init(
     metadata,
     list_templates,
     force,
+    ignore_template_errors,
     describe,
     datadir,
     initial_branch,
@@ -319,6 +325,7 @@ def init(
         input_parameters=parameters,
         custom_metadata=custom_metadata,
         force=force,
+        ignore_template_errors=ignore_template_errors,
         data_dir=datadir,
         initial_branch=initial_branch,
         install_mergetool=True,