cache jinja templates to speed provisioning

brian_dashboard_manager/templating/render.py

@@ -7,6 +7,63 @@ import json
 import jinja2
 
 
+def _read_template(filename):
+    """
+    Reads the template from the given filename.
+
+    :param filename: path to the template file
+
+    :return: template
+    """
+    with open(filename) as f:
+        return jinja2.Template(f.read())
+
+
+dropdown_template_file = os.path.abspath(os.path.join(
+    os.path.dirname(__file__),
+    'templates',
+    'shared',
+    'dropdown.json.j2'))
+
+yaxes_template_file = os.path.abspath(os.path.join(
+    os.path.dirname(__file__),
+    'templates',
+    'shared',
+    'yaxes.json.j2'))
+
+panel_template_file = file = os.path.abspath(os.path.join(
+    os.path.dirname(__file__),
+    'templates',
+    'shared',
+    'panel.json.j2'))
+
+panel_target_template_file = os.path.abspath(os.path.join(
+    os.path.dirname(__file__),
+    'templates',
+    'shared',
+    'panel_target.json.j2'))
+
+nren_dashboard_template_file = os.path.abspath(os.path.join(
+    os.path.dirname(__file__),
+    'templates',
+    'nren_access',
+    'nren-dashboard.json.j2'))
+
+dashboard_template_file = os.path.abspath(os.path.join(
+    os.path.dirname(__file__),
+    'templates',
+    'shared',
+    'dashboard.json.j2'))
+
+
+DROPDOWN_TEMPLATE = _read_template(dropdown_template_file)
+YAXES_TEMPLATE = _read_template(yaxes_template_file)
+PANEL_TEMPLATE = _read_template(panel_template_file)
+PANEL_TARGET_TEMPLATE = _read_template(panel_target_template_file)
+NREN_DASHBOARD_TEMPLATE = _read_template(nren_dashboard_template_file)
+DASHBOARD_TEMPLATE = _read_template(dashboard_template_file)
+
+
 def create_dropdown_panel(title, **kwargs):
     """
     Creates a dropdown panel from the given data.
@@ -17,14 +74,7 @@ def create_dropdown_panel(title, **kwargs):
     :return: rendered dropdown panel JSON
     """
 
-    TEMPLATE_FILENAME = os.path.abspath(os.path.join(
-        os.path.dirname(__file__),
-        'templates',
-        'shared',
-        'dropdown.json.j2'))
-    with open(TEMPLATE_FILENAME) as f:
-        template = jinja2.Template(f.read())
-    return template.render({**kwargs, 'title': title})
+    return DROPDOWN_TEMPLATE.render({**kwargs, 'title': title})
 
 
 def create_yaxes(type):
@@ -36,14 +86,7 @@ def create_yaxes(type):
     :return: rendered yaxes JSON
     """
 
-    file = os.path.abspath(os.path.join(
-        os.path.dirname(__file__),
-        'templates',
-        'shared',
-        'yaxes.json.j2'))
-    with open(file) as f:
-        template = jinja2.Template(f.read())
-    return template.render({'type': type})
+    return YAXES_TEMPLATE.render({'type': type})
 
 
 def create_panel_target(data):
@@ -56,14 +99,7 @@ def create_panel_target(data):
     :return: rendered panel target JSON
     """
 
-    file = os.path.abspath(os.path.join(
-        os.path.dirname(__file__),
-        'templates',
-        'shared',
-        'panel_target.json.j2'))
-    with open(file) as f:
-        template = jinja2.Template(f.read())
-    return template.render(data)
+    return PANEL_TARGET_TEMPLATE.render(data)
 
 
 def create_panel(data):
@@ -76,18 +112,11 @@ def create_panel(data):
     :return: rendered panel JSON
     """
 
-    file = os.path.abspath(os.path.join(
-        os.path.dirname(__file__),
-        'templates',
-        'shared',
-        'panel.json.j2'))
-    with open(file) as f:
-        template = jinja2.Template(f.read())
     yaxes = create_yaxes(data.get('y_axis_type', 'bits'))
     targets = data.get('targets', [])
     for target in data.get('panel_targets', []):
         targets.append(create_panel_target(target))
-    return template.render({**data, 'yaxes': yaxes, 'targets': targets})
+    return PANEL_TEMPLATE.render({**data, 'yaxes': yaxes, 'targets': targets})
 
 
 def render_dashboard(dashboard, nren=False):
@@ -103,20 +132,10 @@ def render_dashboard(dashboard, nren=False):
     """
 
     if nren:
-        file = os.path.abspath(os.path.join(
-            os.path.dirname(__file__),
-            'templates',
-            'nren_access',
-            'nren-dashboard.json.j2'))
+        template = NREN_DASHBOARD_TEMPLATE
     else:
-        file = os.path.abspath(os.path.join(
-            os.path.dirname(__file__),
-            'templates',
-            'shared',
-            'dashboard.json.j2'))
-
-    with open(file) as f:
-        template = jinja2.Template(f.read())
+        template = DASHBOARD_TEMPLATE
+
     rendered = template.render(dashboard)
     rendered = json.loads(rendered)
     rendered['uid'] = None