add support for Jinja2 in task file

Add support in task file for the template syntax based on Jinja2.

JIRA:YARDSTICK-101

Change-Id: I24be133ba590510612d97a1fce6c024e6edb57e4
Signed-off-by: kubi <jean.gaoliang@huawei.com>

1 files changed, 53 insertions, 0 deletions

diff --git a/yardstick/common/task_template.py b/yardstick/common/task_template.py
new file mode 100755
index 000000000..2739323bd
--- /dev/null
+++ b/yardstick/common/task_template.py
@@ -0,0 +1,53 @@
+##############################################################################
+# Copyright (c) 2015 Huawei Technologies Co.,Ltd and others.
+#
+# All rights reserved. This program and the accompanying materials
+# are made available under the terms of the Apache License, Version 2.0
+# which accompanies this distribution, and is available at
+# http://www.apache.org/licenses/LICENSE-2.0
+# yardstick: this file is copied from rally and slightly modified
+##############################################################################
+import re
+import jinja2
+import jinja2.meta
+
+
+class TaskTemplate(object):
+    @classmethod
+    def render(cls, task_template, **kwargs):
+        """Render jinja2 task template to Yardstick input task.
+
+        :param task_template: string that contains template
+        :param kwargs: Dict with template arguments
+        :returns:rendered template str
+        """
+
+        from six.moves import builtins
+
+        ast = jinja2.Environment().parse(task_template)
+        required_kwargs = jinja2.meta.find_undeclared_variables(ast)
+
+        missing = set(required_kwargs) - set(kwargs) - set(dir(builtins))
+        real_missing = [mis for mis in missing
+                        if is_really_missing(mis, task_template)]
+
+        if real_missing:
+            multi_msg = ("Please specify next template task arguments:%s")
+            single_msg = ("Please specify template task argument:%s")
+            raise TypeError((len(real_missing) > 1 and multi_msg or single_msg)
+                            % ", ".join(real_missing))
+        return jinja2.Template(task_template).render(**kwargs)
+
+
+def is_really_missing(mis, task_template):
+    # Removing variables that have default values from
+    # missing. Construction that won't be properly
+    # check is {% set x = x or 1}
+    if re.search(mis.join(["{%\s*set\s+", "\s*=\s*", "[^\w]+"]),
+                 task_template):
+        return False
+    # Also check for a default filter which can show up as
+    # a missing variable
+    if re.search(mis + "\s*\|\s*default\(", task_template):
+        return False
+    return True