A few basic chart improvements

airflow/www/app.py

@@ -127,14 +127,14 @@ class Airflow(BaseView):
 
         all_data = {}
         hook = db.get_hook()
-        jt = jinja2.Template(chart.sql)
         try:
             args = eval(chart.default_params)
         except:
             args = {}
         request_dict = {k:request.args.get(k) for k in request.args}
         args.update(request_dict)
-        sql = jt.render(**args)
+        sql = jinja2.Template(chart.sql).render(**args)
+        label = jinja2.Template(chart.label).render(**args)
         df = hook.get_pandas_df(sql)
 
         for i, (series, x, y) in df.iterrows():
@@ -156,7 +156,7 @@ class Airflow(BaseView):
             chart=chart, data=all_data, table=Markup(table),
             chart_options={},
             height=height,
-            sql=sql)
+            sql=sql, label=label)
         session.commit()
         session.close()
         return response

airflow/www/templates/airflow/modelchart.html

@@ -6,7 +6,7 @@
     <script src="{{ url_for('static', filename='highcharts.js') }}"></script>
     <script src="/ck/static/chartkick.js"></script>
     <div class="container">
-        <h2>{{ chart.label }}</h2>
+        <h2>{{ label }}</h2>
         {% if chart.chart_type == "area_chart" %}
             {% area_chart data with height=height library=chart_options%}
         {% elif chart.chart_type == "line_chart" %}