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, 141 insertions, 0 deletions

diff --git a/docs/Yardstick_task_templates.rst b/docs/Yardstick_task_templates.rst
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+Task Template Syntax
+====================
+
+Basic template syntax
+---------------------
+A nice feature of the input task format used in Yardstick is that it supports the template syntax based on Jinja2.
+This turns out to be extremely useful when, say, you have a fixed structure of your task but you want to
+parameterize this task in some way.
+For example, imagine your input task file (task.yaml) runs a set of Ping scenarios:
+
+::
+
+  # Sample benchmark task config file
+  # measure network latency using ping
+  schema: "yardstick:task:0.1"
+
+  scenarios:
+  -
+    type: Ping
+    options:
+      packetsize: 200
+    host: athena.demo
+    target: ares.demo
+
+    runner:
+      type: Duration
+      duration: 60
+      interval: 1
+
+    sla:
+      max_rtt: 10
+      action: monitor
+
+  context:
+      ...
+
+Let's say you want to run the same set of scenarios with the same runner/context/sla,
+but you want to try another packetsize to compare the performance.
+The most elegant solution is then to turn the packetsize name into a template variable:
+
+::
+
+  # Sample benchmark task config file
+  # measure network latency using ping
+
+  schema: "yardstick:task:0.1"
+  scenarios:
+  -
+    type: Ping
+    options:
+      packetsize: {{packetsize}}
+    host: athena.demo
+    target: ares.demo
+
+    runner:
+      type: Duration
+      duration: 60
+      interval: 1
+
+    sla:
+      max_rtt: 10
+      action: monitor
+
+  context:
+      ...
+
+and then pass the argument value for {{packetsize}} when starting a task with this configuration file.
+Yardstick provides you with different ways to do that:
+
+1.Pass the argument values directly in the command-line interface (with either a JSON or YAML dictionary):
+
+::
+
+ yardstick task start samples/ping-template.yaml --task-args '{"packetsize": "200"}'
+
+2.Refer to a file that specifies the argument values (JSON/YAML):
+
+::
+
+ yardstick task start samples/ping-template.yaml --task-args-file args.yaml
+
+Using the default values
+------------------------
+Note that the Jinja2 template syntax allows you to set the default values for your parameters.
+With default values set, your task file will work even if you don't parameterize it explicitly while starting a task.
+The default values should be set using the {% set ... %} clause (task.yaml).For example:
+
+::
+
+  # Sample benchmark task config file
+  # measure network latency using ping
+  schema: "yardstick:task:0.1"
+  {% set packetsize = packetsize or "100" %}
+  scenarios:
+  -
+    type: Ping
+    options:
+    packetsize: {{packetsize}}
+    host: athena.demo
+    target: ares.demo
+
+    runner:
+      type: Duration
+      duration: 60
+      interval: 1
+    ...
+
+If you don't pass the value for {{packetsize}} while starting a task, the default one will be used.
+
+Advanced templates
+------------------
+Yardstick makes it possible to use all the power of Jinja2 template syntax, including the mechanism of built-in functions.
+As an example, let us make up a task file that will do a block storage performance test.
+The input task file (fio-template.yaml) below uses the Jinja2 for-endfor construct to accomplish that:
+
+::
+
+  #Test block sizes of 4KB, 8KB, 64KB, 1MB
+  #Test 5 workloads: read, write, randwrite, randread, rw
+  schema: "yardstick:task:0.1"
+
+   scenarios:
+  {% for bs in ['4k', '8k', '64k', '1024k' ] %}
+    {% for rw in ['read', 'write', 'randwrite', 'randread', 'rw' ] %}
+  -
+    type: Fio
+    options:
+      filename: /home/ec2-user/data.raw
+      bs: {{bs}}
+      rw: {{rw}}
+      ramp_time: 10
+    host: fio.demo
+    runner:
+      type: Duration
+      duration: 60
+      interval: 60
+
+    {% endfor %}
+  {% endfor %}
+  context
+      ...