From 4ae36a0dc35b62773bccb7288557622e8964296e Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Sybren=20A=2E=20St=C3=BCvel?= <sybren@stuvel.eu>
Date: Tue, 6 Sep 2016 18:39:35 +0200
Subject: [PATCH] Allow custom template dirs for extensions

---
 pillar/__init__.py  | 20 +++++++++++++++++++-
 pillar/extension.py |  9 +++++++++
 2 files changed, 28 insertions(+), 1 deletion(-)

diff --git a/pillar/__init__.py b/pillar/__init__.py
index c7fb9ebc..24e543da 100644
--- a/pillar/__init__.py
+++ b/pillar/__init__.py
@@ -37,6 +37,7 @@ class PillarServer(Eve):
         super(PillarServer, self).__init__(settings=empty_settings, **kwargs)
 
         self.pillar_extensions = {}  # mapping from extension name to extension object.
+        self.pillar_extensions_template_paths = []  # list of paths
 
         self.app_root = os.path.abspath(app_root)
         self._load_flask_config()
@@ -198,6 +199,16 @@ class PillarServer(Eve):
         for blueprint in pillar_extension.blueprints():
             self.register_blueprint(blueprint, url_prefix=url_prefix)
 
+        # Load template paths
+        tpath = pillar_extension.template_path
+        if tpath:
+            self.log.info('Extension %s: adding template path %s',
+                          pillar_extension.name, tpath)
+            if not os.path.exists(tpath):
+                raise ValueError('Template path %s for extension %s does not exist.',
+                                 tpath, pillar_extension.name)
+            self.pillar_extensions_template_paths.append(tpath)
+
         # Load extension Eve settings
         eve_settings = pillar_extension.eve_settings()
 
@@ -212,10 +223,17 @@ class PillarServer(Eve):
             self.config['DOMAIN'].update(eve_settings['DOMAIN'])
 
     def _config_jinja_env(self):
+        # Start with the extensions...
+        paths_list = [
+            jinja2.FileSystemLoader(path)
+            for path in reversed(self.pillar_extensions_template_paths)
+        ]
+
+        # ...then load Pillar paths.
         pillar_dir = os.path.dirname(os.path.realpath(__file__))
         parent_theme_path = os.path.join(pillar_dir, 'web', 'templates')
         current_path = os.path.join(self.app_root, 'templates')
-        paths_list = [
+        paths_list += [
             jinja2.FileSystemLoader(current_path),
             jinja2.FileSystemLoader(parent_theme_path),
             self.jinja_loader
diff --git a/pillar/extension.py b/pillar/extension.py
index 0c7b3e3a..dd6f0f67 100644
--- a/pillar/extension.py
+++ b/pillar/extension.py
@@ -63,5 +63,14 @@ class PillarExtension(object):
         :rtype: dict
         """
 
+    @property
+    def template_path(self):
+        """Returns the path where templates for this extension are stored.
+
+        Note that this path is not connected to any blueprint, so it is up to
+        the extension to provide extension-unique subdirectories.
+        """
+        return None
+
     def setup_app(self, app):
         """Called during app startup, after all extensions have loaded."""