Added two new Rally scenarios

the new scenarios are a workflow that contains Jinja,
Yaql expressions on a relatively big json object
(4mb in size).

the input for these two Scenarios is :
 1. the number of tasks in the workflow
    - 30 in rally task
 2. the size of the param object in mb
    - 4mb in rally task

Change-Id: Ib33f26573b4b46a628f7d1d28fd18dedcb9c4738

.zuul.yaml

@@ -7,6 +7,11 @@
       rally_task: rally-jobs/task-mistral.yaml
       devstack_localrc:
         USE_PYTHON3: true
+      devstack_local_conf:
+        post-config:
+          $MISTRAL_CONF_FILE:
+            engine:
+              execution_field_size_limit_kb: 8192
     required-projects:
       - openstack/rally-openstack
       - openstack/mistral-lib

rally-jobs/plugins/mistral_expressions_scenario.py

@@ -0,0 +1,142 @@
+# Copyright 2020 - Nokia Software.
+#
+#    Licensed under the Apache License, Version 2.0 (the "License");
+#    you may not use this file except in compliance with the License.
+#    You may obtain a copy of the License at
+#
+#        http://www.apache.org/licenses/LICENSE-2.0
+#
+#    Unless required by applicable law or agreed to in writing, software
+#    distributed under the License is distributed on an "AS IS" BASIS,
+#    WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+#    See the License for the specific language governing permissions and
+#    limitations under the License.
+
+
+import json
+import math
+import random
+import string
+
+from rally.task import validation
+from rally_openstack import consts
+from rally_openstack import scenario
+from rally_openstack.scenarios.mistral import utils
+
+
+def random_string(length=10):
+    """Generate a random string of given length """
+
+    letters = string.ascii_lowercase
+
+    return ''.join(random.choices(letters, k=length))
+
+
+class MistralExpressionScenario(utils.MistralScenario):
+
+    def run(self, tasks_number=50, params_size_mb=5):
+        wf_text, wf_name = self.create_wf_string(tasks_number)
+        params = self.create_params(params_size_mb)
+
+        self._create_workflow(wf_text)
+        self._create_execution(wf_name, **params)
+
+    def create_params(self, size_mb):
+        block_size_mb = 0.2
+        rand_string = random_string(105400)
+        number_of_fields = math.floor(size_mb / block_size_mb)
+        data_list = ''
+        #  each one of these blocks is 200kb
+        data_template = """
+                "data%s":
+                {
+                  "dummy": 5470438,
+                  "data_value": -796997888,
+                  "sub_data":
+                  {
+                    "meta_data":
+                    {
+                      "value": "%s",
+                      "text": "dummy text"
+                    },
+                    "field1": "%s",
+                    "field2": false,
+                    "field3":
+                    {
+                      "value1": -1081872761.2081857,
+                      "value2": -1081872761.2081857
+                    }
+                  }
+                },
+"""
+        wf_params = """
+        {
+          "field": "some Value",
+            "data":
+              {
+                {{{__DATA_LIST__}}}
+              }
+        }
+"""
+        for i in range(1, int(number_of_fields + 1)):
+            data_list += data_template % (i, rand_string, rand_string)
+
+        data_list = data_list[:-2]
+
+        wf_params = wf_params.replace('{{{__DATA_LIST__}}}', data_list)
+        params = json.loads(wf_params)
+
+        return params
+
+    def get_query(self):
+        raise NotImplementedError
+
+    def create_wf_string(self, tasks_number):
+        wf_tasks = ''
+        wf_name = 'wf_{}'.format(random_string(5))
+
+        query = self.get_query()
+
+        wf_text = """
+            version: '2.0'
+            {}:
+              tasks:
+                task0:
+                  action: std.noop
+                {{{__TASK_LIST__}}}
+            """
+        task_template = """
+                task{}:
+                  action: std.noop
+                  publish:
+                     output{}: {}
+            """
+
+        for i in range(1, tasks_number + 1):
+            wf_tasks += task_template.format(i, i, query)
+
+        wf_text = wf_text.replace('{{{__TASK_LIST__}}}', wf_tasks)
+
+        wf_text = wf_text.format(wf_name)
+
+        return wf_text, wf_name
+
+
+@validation.add("required_platform", platform="openstack", users=True)
+@validation.add("required_services", services=[consts.Service.MISTRAL])
+@scenario.configure(name="MistralExecutions.YaqlExpression",
+                    platform="openstack")
+class YaqlExpressionScenario(MistralExpressionScenario):
+
+    def get_query(self):
+        return '<% data %>'
+
+
+@validation.add("required_platform", platform="openstack", users=True)
+@validation.add("required_services", services=[consts.Service.MISTRAL])
+@scenario.configure(name="MistralExecutions.JinjaExpression",
+                    platform="openstack")
+class JinjaExpressionScenario(MistralExpressionScenario):
+
+    def get_query(self):
+        return '{{ data }} '

rally-jobs/task-mistral.yaml

@@ -162,3 +162,37 @@
       sla:
         failure_rate:
           max: 0
+
+  MistralExecutions.YaqlExpression:
+    -
+      args:
+        tasks_number: 30
+        params_size_mb: 4
+      runner:
+        type: "constant"
+        times: 50
+        concurrency: 10
+      context:
+        users:
+          tenants: 1
+          users_per_tenant: 1
+      sla:
+        failure_rate:
+          max: 0
+
+  MistralExecutions.JinjaExpression:
+    -
+      args:
+        tasks_number: 30
+        params_size_mb: 4
+      runner:
+        type: "constant"
+        times: 50
+        concurrency: 10
+      context:
+        users:
+          tenants: 1
+          users_per_tenant: 1
+      sla:
+        failure_rate:
+          max: 0