Changing YAQL syntax delimeters

* Inline YAQL delimeters are changed on '<%' and '%>' Implements blueprint yaql-delimiters Change-Id: I31fbf5175d10684e7799e835d175517d2dadab9b
2015-02-20 14:58:50 +03:00 · 2015-02-20 14:58:50 +03:00 · b4a7ebeb01
commit b4a7ebeb01
parent 32d09b5aca
49 changed files with 318 additions and 307 deletions
--- a/mistral/expressions.py
+++ b/mistral/expressions.py
@ -76,12 +76,13 @@ class YAQLEvaluator(Evaluator):
        return isinstance(s, six.string_types)


+INLINE_YAQL_REGEXP = '<%.*?%>'
+
+
 class InlineYAQLEvaluator(YAQLEvaluator):
    # This regular expression will look for multiple occurrences of YAQL
-    # expressions in between curly braces (i.e. {any_symbols_except'}'})
-    # within a string.
-    regex_yaql_expr = '(\{[^\s][^}]*\})'
-    find_expression_pattern = re.compile(regex_yaql_expr)
+    # expressions in '<% %>' (i.e. <% any_symbols %>) within a string.
+    find_expression_pattern = re.compile(INLINE_YAQL_REGEXP)

    @classmethod
    def evaluate(cls, expression, data_context):
@ -94,7 +95,7 @@ class InlineYAQLEvaluator(YAQLEvaluator):
        found_expressions = cls.find_inline_expressions(expression)
        if found_expressions:
            for expr in found_expressions:
-                trim_expr = expr.strip("{}")
+                trim_expr = expr.strip("<%>")
                evaluated = super(InlineYAQLEvaluator,
                                  cls).evaluate(trim_expr, data_context)
                if len(expression) == len(expr):
--- a/mistral/tests/resources/action_v2.yaml
+++ b/mistral/tests/resources/action_v2.yaml
@ -6,16 +6,16 @@ greeting:
  tags: [hello]
  base: std.echo
  base-input:
-    output: 'Hello,  {$.name}'
+    output: 'Hello,  <% $.name %>'
  input:
    - name
  output:
-    string: "{$.output}"
+    string: <% $.output %>

 farewell:
  base: std.echo
  base-input:
    output: 'Bye!'
  output:
-    info: "{$.output}"
+    info: <% $.output %>

--- a/mistral/tests/resources/control_flow/direct_flow.yaml
+++ b/mistral/tests/resources/control_flow/direct_flow.yaml
@ -4,7 +4,7 @@ Namespaces:
    base-parameters:
      method: GET
      headers:
-        X-Auth-Token: "{$.auth_token}"
+        X-Auth-Token: <% $.auth_token %>

    actions:
      async-action:
--- a/mistral/tests/resources/control_flow/one_async_task.yaml
+++ b/mistral/tests/resources/control_flow/one_async_task.yaml
@ -4,7 +4,7 @@ Namespaces:
    base-parameters:
      method: GET
      headers:
-        X-Auth-Token: "{$.auth_token}"
+        X-Auth-Token: <% $.auth_token %>

    actions:
      create-vm:
--- a/mistral/tests/resources/control_flow/one_std_task.yaml
+++ b/mistral/tests/resources/control_flow/one_std_task.yaml
@ -6,7 +6,7 @@ Namespaces:
        base-parameters:
          url: http://path_to_nova/url_for_create
        output:
-          vm_id: "{$.base_output.server_id}"
+          vm_id: <% $.base_output.server_id %>

 Workflow:
  tasks:
--- a/mistral/tests/resources/control_flow/one_sync_task.yaml
+++ b/mistral/tests/resources/control_flow/one_sync_task.yaml
@ -4,12 +4,12 @@ Namespaces:
      concat:
        class: std.echo
        base-parameters:
-          output: '{$.left} {$.right}'
+          output: '<% $.left %> <% $.right %>'
        parameters:
          - left
          - right
        output:
-          string: "{$.output}"
+          string: <% $.output %>

 Workflow:
  tasks:
--- a/mistral/tests/resources/control_flow/require_flow.yaml
+++ b/mistral/tests/resources/control_flow/require_flow.yaml
@ -4,18 +4,18 @@ Namespaces:
      concat:
        class: std.echo
        base-parameters:
-          output: '{$.left} {$.right}'
+          output: '<% $.left %> <% $.right %>'
        parameters:
          - left
          - right
        output:
-          string: "{$.output}"
+          string: <% $.output %>
      start:
        class: std.echo
        base-parameters:
          output: 'Starting...'
        output:
-          info: "{$.output}"
+          info: <% $.output %>

 Workflow:
  tasks:
@ -31,4 +31,4 @@ Workflow:
      action: MyActions.concat
      parameters:
        left: Greetings
-        right: "{$.string}"
+        right: <% $.string %>
--- a/mistral/tests/resources/data_flow/task_with_diamond_dependencies.yaml
+++ b/mistral/tests/resources/data_flow/task_with_diamond_dependencies.yaml
@ -7,12 +7,12 @@ Namespaces:
      concat:
        class: std.echo
        base-parameters:
-          output: '{$.left} {$.right}'
+          output: '<% $.left %> <% $.right %>'
        parameters:
          - left
          - right
        output:
-          string: "{$}"
+          string: <% $ %>

 Workflow:
  #  context = {
@ -31,32 +31,32 @@ Workflow:
    build_full_name:
      action: MyService.concat
      parameters:
-        left: "{$.person.first_name}"
-        right: "{$.person.last_name}"
+        left: <% $.person.first_name %>
+        right: <% $.person.last_name %>
      publish:
-        full_name: "{$.string}"
+        full_name: <% $.string %>

    build_greeting:
      requires: [build_full_name]
      action: MyService.concat
      parameters:
        left: Dear
-        right: "{$.full_name}"
+        right: <% $.full_name %>
      publish:
-        greeting: "{$.string}"
+        greeting: <% $.string %>

    build_address:
      requires: [build_full_name]
      action: MyService.concat
      parameters:
        left: To
-        right: "{$.full_name}"
+        right: <% $.full_name %>
      publish:
-        address: "{$.string}"
+        address: <% $.string %>

    send_greeting:
      requires: [build_address, build_greeting]
      action: MyService.concat
      parameters:
-        left: '{$.address}.'
-        right: '{$.greeting},..'
+        left: '<% $.address %>.'
+        right: '<% $.greeting %>,..'
--- a/mistral/tests/resources/data_flow/task_with_two_dependencies.yaml
+++ b/mistral/tests/resources/data_flow/task_with_two_dependencies.yaml
@ -7,19 +7,19 @@ Namespaces:
      build_full_name:
        class: std.echo
        base-parameters:
-          output: '{$.first_name} {$.last_name}'
+          output: '<% $.first_name %> <% $.last_name %>'
        parameters:
          - first_name
          - last_name
        output:
-          full_name: "{$}"
+          full_name: <% $ %>

      build_greeting:
        class: std.echo
        base-parameters:
          output: Cheers!
        output:
-          greeting: "{$}"
+          greeting: <% $ %>

      send_greeting:
        class: std.echo
@ -29,7 +29,7 @@ Namespaces:
          - f_name
          - greet_msg
        output:
-          greeting_sent: "{$}"
+          greeting_sent: <% $ %>

 Workflow:
  #  context = {
@ -48,20 +48,20 @@ Workflow:
    build_full_name:
      action: MyService.build_full_name
      parameters:
-        first_name: "{$.person.first_name}"
-        last_name: "{$.person.last_name}"
+        first_name: <% $.person.first_name %>
+        last_name: <% $.person.last_name %>
      publish:
-        f_name: "{$.full_name}"
+        f_name: <% $.full_name %>

    build_greeting:
      requires: [build_full_name]
      action: MyService.build_greeting
      publish:
-        greet_msg: "{$.greeting}"
+        greet_msg: <% $.greeting %>

    send_greeting:
      requires: [build_full_name, build_greeting]
      action: MyService.send_greeting
      parameters:
-        f_name: "{$.f_name}"
-        greet_msg: "{$.greet_msg}"
+        f_name: <% $.f_name %>
+        greet_msg: <% $.greet_msg %>
--- a/mistral/tests/resources/data_flow/three_subsequent_tasks.yaml
+++ b/mistral/tests/resources/data_flow/three_subsequent_tasks.yaml
@ -7,21 +7,21 @@ Namespaces:
      build_full_name:
        class: std.echo
        base-parameters:
-          output: '{$.first_name} {$.last_name}'
+          output: '<% $.first_name %> <% $.last_name %>'
        parameters:
          - first_name
          - last_name
        output:
-          full_name: "{$}"
+          full_name: <% $ %>

      build_greeting:
        class: std.echo
        base-parameters:
-          output: 'Hello, {$.full_name}!'
+          output: 'Hello, <% $.full_name %>!'
        parameters:
          - full_name
        output:
-          greeting: "{$}"
+          greeting: <% $ %>

      send_greeting:
        class: std.echo
@ -30,7 +30,7 @@ Namespaces:
        parameters:
          - greeting
        output:
-          greeting_sent: "{$}"
+          greeting_sent: <% $ %>


 Workflow:
@ -50,23 +50,23 @@ Workflow:
    build_full_name:
      action: MyService.build_full_name
      parameters:
-        first_name: "{$.person.first_name}"
-        last_name: "{$.person.last_name}"
+        first_name: <% $.person.first_name %>
+        last_name: <% $.person.last_name %>
      publish:
-        f_name: "{$.full_name}"
+        f_name: <% $.full_name %>
      on-success: build_greeting

    build_greeting:
      action: MyService.build_greeting
      parameters:
-        full_name: "{$.f_name}"
+        full_name: <% $.f_name %>
      publish:
-        greet_msg: "{$.greeting}"
+        greet_msg: <% $.greeting %>
      on-success: send_greeting

    send_greeting:
      action: MyService.send_greeting
      parameters:
-        greeting: "{$.task.build_greeting.greeting}"
+        greeting: <% $.task.build_greeting.greeting %>
      publish:
-        sent: "{$.greeting_sent}"
+        sent: <% $.greeting_sent %>
--- a/mistral/tests/resources/data_flow/two_dependent_tasks.yaml
+++ b/mistral/tests/resources/data_flow/two_dependent_tasks.yaml
@ -7,21 +7,21 @@ Namespaces:
      build_full_name:
        class: std.echo
        base-parameters:
-          output: '{$.first_name} {$.last_name}'
+          output: '<% $.first_name %> <% $.last_name %>'
        parameters:
          - first_name
          - last_name
        output:
-          full_name: "{$}"
+          full_name: <% $ %>

      build_greeting:
        class: std.echo
        base-parameters:
-          output: 'Hello, {$.full_name}!'
+          output: 'Hello, <% $.full_name %>!'
        parameters:
          - full_name
        output:
-          greeting: "{$}"
+          greeting: <% $ %>


 Workflow:
@ -41,13 +41,13 @@ Workflow:
    build_full_name:
      action: MyService.build_full_name
      parameters:
-        first_name: "{$.person.first_name}"
-        last_name: "{$.person.last_name}"
+        first_name: <% $.person.first_name %>
+        last_name: <% $.person.last_name %>
      publish:
-        f_name: "{$.full_name}"
+        f_name: <% $.full_name %>

    build_greeting:
      requires: [build_full_name]
      action: MyService.build_greeting
      parameters:
-        full_name: "{$.f_name}"
+        full_name: <% $.f_name %>
--- a/mistral/tests/resources/data_flow/two_subsequent_tasks.yaml
+++ b/mistral/tests/resources/data_flow/two_subsequent_tasks.yaml
@ -7,22 +7,22 @@ Namespaces:
      build_full_name:
        class: std.echo
        base-parameters:
-          output: '{$.first_name} {$.last_name}'
+          output: '<% $.first_name %> <% $.last_name %>'
        parameters:
          - first_name
          - last_name
        output:
-          full_name: "{$}"
+          full_name: <% $ %>

      build_greeting:
        class: std.echo
        base-parameters:
-          output: 'Hello, {$.full_name}!'
+          output: 'Hello, <% $.full_name %>!'
        parameters:
          - full_name
        output:
          greeting:
-            greet_message: "{$}"
+            greet_message: <% $ %>


 Workflow:
@ -42,15 +42,15 @@ Workflow:
    build_full_name:
      action: MyService.build_full_name
      parameters:
-        first_name: "{$.person.first_name}"
-        last_name: "{$.person.last_name}"
+        first_name: <% $.person.first_name %>
+        last_name: <% $.person.last_name %>
      publish:
-        f_name: "{$.full_name}"
+        f_name: <% $.full_name %>
      on-success: build_greeting

    build_greeting:
      action: MyService.build_greeting
      parameters:
-        full_name: "{$.f_name}"
+        full_name: <% $.f_name %>
      publish:
-        greet_msg: "{$.greeting}"
+        greet_msg: <% $.greeting %>
--- a/mistral/tests/resources/openstack/action_collection_wb.yaml
+++ b/mistral/tests/resources/openstack/action_collection_wb.yaml
@ -9,7 +9,7 @@ workflows:
      catalog:
        action: keystone.service_catalog_get_data
        publish:
-           result: "{$.catalog}"
+           result: <% $.catalog %>

  nova:
    type: direct
@ -17,7 +17,7 @@ workflows:
      networks_list:
        action: nova.networks_list
        publish:
-           result: "{$.networks_list}"
+           result: <% $.networks_list %>

  glance:
    type: direct
@ -25,7 +25,7 @@ workflows:
      images_list:
        action: glance.images_list
        publish:
-           result: "{$.images_list}"
+           result: <% $.images_list %>

  heat:
    type: direct
@ -33,7 +33,7 @@ workflows:
      stacks_list:
        action: heat.stacks_list
        publish:
-           result: "{$.stacks_list}"
+           result: <% $.stacks_list %>

  neutron:
    type: direct
@ -41,7 +41,7 @@ workflows:
      list_subnets:
        action: neutron.list_subnets
        publish:
-           result: "{$.list_subnets}"
+           result: <% $.list_subnets %>

  cinder:
    type: direct
@ -49,5 +49,5 @@ workflows:
      volumes_list:
        action: cinder.volumes_list
        publish:
-           result: "{$.volumes_list}"
+           result: <% $.volumes_list %>

--- a/mistral/tests/resources/openstack/glance_actions.yaml
+++ b/mistral/tests/resources/openstack/glance_actions.yaml
@ -3,13 +3,13 @@ Workflow:
    image_list:
      action: glance.images_list
      publish:
-        image_id: "{$[0].id}"
+        image_id: <% $[0].id %>
      on-success: image_get

    image_get:
      action: glance.images_get
      parameters:
-        image_id: "{$.image_id}"
+        image_id: <% $.image_id %>
      publish:
-        image_id: "{$.id}"
-        image_name: "{$.name}"
+        image_id: <% $.id %>
+        image_name: <% $.name %>
--- a/mistral/tests/resources/openstack/keystone_actions.yaml
+++ b/mistral/tests/resources/openstack/keystone_actions.yaml
@ -3,4 +3,4 @@ Workflow:
    get_some_endpoint:
      action: keystone.service_catalog_get_data
      publish:
-        endpoint_url: "{$[0].endpoints[0].url}"
+        endpoint_url: <% $[0].endpoints[0].url %>
--- a/mistral/tests/resources/openstack/nova_actions.yaml
+++ b/mistral/tests/resources/openstack/nova_actions.yaml
@ -3,17 +3,17 @@ Workflow:
    server_create:
      action: nova.servers_create
      parameters:
-        name: "{$.server_name}"
-        image: "{$.image_ref}"
-        flavor: "{$.flavor_ref}"
+        name: <% $.server_name %>
+        image: <% $.image_ref %>
+        flavor: <% $.flavor_ref %>
      publish:
-        server_id: "{$.id}"
+        server_id: <% $.id %>
      on-success: check_server_exists

    check_server_exists:
      action: nova.servers_get
      parameters:
-        server: "{$.server_id}"
+        server: <% $.server_id %>
      publish:
        server_exists: True
      on-success:
@ -25,7 +25,7 @@ Workflow:
        delay: 5
        count: 15
      parameters:
-        id: "{$.server_id}"
+        id: <% $.server_id %>
        status: 'ACTIVE'
      publish:
-        instance_id: "{$.id}"
+        instance_id: <% $.id %>
--- a/mistral/tests/resources/retry_task/delay_retry_task.yaml
+++ b/mistral/tests/resources/retry_task/delay_retry_task.yaml
@ -7,7 +7,7 @@ Namespaces:
          url: http://path_to_service/action_url
          method: GET
        output:
-          output: "{$}"
+          output: <% $ %>

 Workflow:
  tasks:
--- a/mistral/tests/resources/retry_task/retry_task.yaml
+++ b/mistral/tests/resources/retry_task/retry_task.yaml
@ -7,7 +7,7 @@ Namespaces:
          url: http://path_to_service/action_url
          method: GET
        output:
-          output: "{$}"
+          output: <% $ %>

 Workflow:
  tasks:
@ -16,4 +16,4 @@ Workflow:
      retry:
        count: 5
      publish:
-        rt_output: "{$.output}"
+        rt_output: <% $.output %>
--- a/mistral/tests/resources/retry_task/sync_task.yaml
+++ b/mistral/tests/resources/retry_task/sync_task.yaml
@ -6,7 +6,7 @@ Namespaces:
        base-parameters:
          output: Cheers!
        output:
-          greeting: "{$}"
+          greeting: <% $ %>

 Workflow:
  tasks:
@ -15,4 +15,4 @@ Workflow:
      retry:
        count: 5
      publish:
-        st_output: "{$.greeting}"
+        st_output: <% $.greeting %>
--- a/mistral/tests/resources/retry_task/two_tasks.yaml
+++ b/mistral/tests/resources/retry_task/two_tasks.yaml
@ -7,14 +7,14 @@ Namespaces:
          url: http://path_to_service/action_url
          method: GET
        output:
-          output: "{$}"
+          output: <% $ %>

 Workflow:
  tasks:
    no_retry_task:
      action: MyService.some-action
      publish:
-        n_rt_output: "{$.output}"
+        n_rt_output: <% $.output %>
      on-success: delay_retry_task

    delay_retry_task:
--- a/mistral/tests/resources/test_direct_flow_all_keywords.yaml
+++ b/mistral/tests/resources/test_direct_flow_all_keywords.yaml
@ -4,7 +4,7 @@ Namespaces:
    base-parameters:
      method: GET
      headers:
-        X-Auth-Token: "{$.auth_token}"
+        X-Auth-Token: <% $.auth_token %>

    actions:
      create-vm:
@ -21,12 +21,12 @@ Namespaces:
      concat:
        class: std.echo
        base-parameters:
-          output: '{$.left} {$.right}'
+          output: '<% $.left %> <% $.right %>'
        parameters:
          - left
          - right
        output:
-          string: "{$}"
+          string: <% $ %>

 Workflow:
  tasks:
@ -43,7 +43,7 @@ Workflow:
        left: workflow
        right: is
      publish:
-        result2: "{$.string}"
+        result2: <% $.string %>
      on-finish: task3

    task3:
@ -56,8 +56,8 @@ Workflow:
    task4:
      action: Echo.concat
      parameters:
-        left: "{$.result2}"
+        left: <% $.result2 %>
        right: complete!
      publish:
-        result4: "{$.string}"
+        result4: <% $.string %>

--- a/mistral/tests/resources/test_mixed_flow.yaml
+++ b/mistral/tests/resources/test_mixed_flow.yaml
@ -4,12 +4,12 @@ Namespaces:
      concat:
        class: std.echo
        base-parameters:
-          output: '{$.left} {$.right}'
+          output: '<% $.left %> <% $.right %>'
        parameters:
          - left
          - right
        output:
-          string: "{$}"
+          string: <% $ %>

 Workflow:
  tasks:
@ -19,22 +19,22 @@ Workflow:
        left: workflow
        right: is
      publish:
-        result1: "{$.string}"
+        result1: <% $.string %>

    task2:
      requires: [task1]
      action: MyService.concat
      parameters:
-        left: "{$.result1}"
+        left: <% $.result1 %>
        right:  complete
      publish:
-        result2: "{$.string}"
+        result2: <% $.string %>
      on-success: task3

    task3:
      action: MyService.concat
      parameters:
-        left: "{$.result2}"
+        left: <% $.result2 %>
        right: '!'
      publish:
-        result3: "{$.string}"
+        result3: <% $.string %>
--- a/mistral/tests/resources/wb_v2.yaml
+++ b/mistral/tests/resources/wb_v2.yaml
@ -10,4 +10,4 @@ workflows:
      hello:
        action: std.echo output="Hello"
        publish:
-           result: "{$.hello}"
+           result: <% $.hello %>
--- a/mistral/tests/resources/wf_v2.yaml
+++ b/mistral/tests/resources/wf_v2.yaml
@ -10,7 +10,7 @@ wf:
      policies:
        wait-before: 1
      publish:
-        result: "{$.hello}"
+        result: <% $.hello %>

 wf1:
  type: reverse
@ -21,9 +21,9 @@ wf1:
    addressee:
      action: std.echo output="John"
      publish:
-        name: "{$.adressee}"
+        name: <% $.adressee %>

    goodbye:
-      action: std.echo output="{$.farewell}, {$.name}"
+      action: std.echo output="<% $.farewell %>, <% $.name %>"
      requires: [addressee]

--- a/mistral/tests/unit/actions/test_action_factory.py
+++ b/mistral/tests/unit/actions/test_action_factory.py
@ -64,11 +64,11 @@ DB_TASK_ADHOC = {
        'namespace': 'my_namespace',
        'class': 'std.echo',
        'base-parameters': {
-            'output': '{$.first} and {$.second}'
+            'output': '<% $.first %> and <% $.second %>'
        },
        'parameters': ['first', 'second'],
        'output': {
-            'res': '{$}'
+            'res': '<% $ %>'
        }
    },
    'name': 'my_task',
--- a/mistral/tests/unit/engine/test_data_flow_module.py
+++ b/mistral/tests/unit/engine/test_data_flow_module.py
@ -46,11 +46,11 @@ TASK = {
        'action': 'std.echo',
        'parameters': {
            'p1': 'My string',
-            'p2': '{$.param3.param32}',
+            'p2': '<% $.param3.param32 %>',
            'p3': ''
        },
        'publish': {
-            'new_key11': '{$.new_key1}'
+            'new_key11': '<% $.new_key1 %>'
        }
    },
    'in_context': CONTEXT
@ -66,7 +66,7 @@ WORKBOOK = {
                'thing': {
                    'class': 'std.echo',
                    'base-parameters': {
-                        'output': '{$.p1} {$.p2}'
+                        'output': '<% $.p1 %> <% $.p2 %>'
                    }
                }
            }
--- a/mistral/tests/unit/engine1/test_action_context.py
+++ b/mistral/tests/unit/engine1/test_action_context.py
@ -46,7 +46,7 @@ workflows:
        input:
          url: https://wiki.openstack.org/wiki/mistral
        publish:
-          result: $
+          result: <% $ %>
 """


--- a/mistral/tests/unit/engine1/test_action_defaults.py
+++ b/mistral/tests/unit/engine1/test_action_defaults.py
@ -52,7 +52,7 @@ wf1:
    task1:
      action: std.http url="https://api.library.org/books"
      publish:
-        result: "{$}"
+        result: <% $ %>
 """

 WORKFLOW2 = """
@ -64,7 +64,7 @@ wf2:
    task1:
      action: std.http url="https://api.library.org/books" timeout=60
      publish:
-        result: "{$}"
+        result: <% $ %>
 """

 WORKFLOW1_WITH_ITEMS = """
@ -76,10 +76,10 @@ wf1_with_items:
    - links
  tasks:
    task1:
-      with-items: link in {$.links}
-      action: std.http url={$.link}
+      with-items: link in <% $.links %>
+      action: std.http url=<% $.link %>
      publish:
-        result: "{$}"
+        result: <% $ %>
 """

 WORKFLOW2_WITH_ITEMS = """
@ -91,10 +91,10 @@ wf2_with_items:
    - links
  tasks:
    task1:
-      with-items: link in {$.links}
-      action: std.http url={$.link} timeout=60
+      with-items: link in <% $.links %>
+      action: std.http url=<% $.link %> timeout=60
      publish:
-        result: "{$}"
+        result: <% $ %>
 """


--- a/mistral/tests/unit/engine1/test_adhoc_actions.py
+++ b/mistral/tests/unit/engine1/test_adhoc_actions.py
@ -36,11 +36,11 @@ actions:
  concat_twice:
    base: std.echo
    base-input:
-      output: "{$.s1}+{$.s2}"
+      output: "<% $.s1 %>+<% $.s2 %>"
    input:
      - s1
      - s2
-    output: "{$} and {$}"
+    output: "<% $ %> and <% $ %>"

 workflows:
  wf1:
@ -49,14 +49,14 @@ workflows:
      - str1
      - str2
    output:
-      workflow_result: "{$.result}" # Access to execution context variables
-      concat_task_result: "{$.concat}" # Access to the same but via task name
+      workflow_result: <% $.result %> # Access to execution context variables
+      concat_task_result: <% $.concat %> # Access to the same but via task name

    tasks:
      concat:
-        action: concat_twice s1={$.str1} s2={$.str2}
+        action: concat_twice s1=<% $.str1 %> s2=<% $.str2 %>
        publish:
-          result: "{$.concat}"
+          result: <% $.concat %>
 """


--- a/mistral/tests/unit/engine1/test_commands.py
+++ b/mistral/tests/unit/engine1/test_commands.py
@ -43,9 +43,9 @@ workflows:
      task1:
        action: std.echo output='1'
        on-complete:
-          - fail: "{$.my_var = 1}"
-          - succeed: "{$.my_var = 2}"
-          - pause: "{$.my_var = 3}"
+          - fail: <% $.my_var = 1 %>
+          - succeed: <% $.my_var = 2 %>
+          - pause: <% $.my_var = 3 %>
          - task2

      task2:
@ -116,11 +116,11 @@ workflows:

    task-defaults:
      on-complete:
-        - fail: "{$.my_var = 1}"
-        - succeed: "{$.my_var = 2}"
-        - pause: "{$.my_var = 3}"
-        - rollback: "{$.my_var = 3}"
-        - task2: "{$.my_var = 4}" # (Never happens in this test)
+        - fail: <% $.my_var = 1 %>
+        - succeed: <% $.my_var = 2 %>
+        - pause: <% $.my_var = 3 %>
+        - rollback: <% $.my_var = 3 %>
+        - task2: <% $.my_var = 4 %> # (Never happens in this test)

    tasks:
      task1:
--- a/mistral/tests/unit/engine1/test_dataflow.py
+++ b/mistral/tests/unit/engine1/test_dataflow.py
@ -42,20 +42,20 @@ wf:
    task1:
      action: std.echo output="Hi"
      publish:
-        hi: "{$.task1}"
+        hi: <% $.task1 %>
      on-success:
        - task2

    task2:
      action: std.echo output="Morpheus"
      publish:
-        to: "{$.task2}"
+        to: <% $.task2 %>
      on-success:
        - task3

    task3:
      publish:
-        result: "{$.hi}, {$.to}! Sincerely, your {$.__env.from}."
+        result: "<% $.hi %>, <% $.to %>! Sincerely, your <% $.__env.from %>."
 """

 PARALLEL_TASKS_WF = """
@ -69,12 +69,12 @@ wf:
    task1:
      action: std.echo output=1
      publish:
-        var1: "{$.task1}"
+        var1: <% $.task1 %>

    task2:
      action: std.echo output=2
      publish:
-        var2: "{$.task2}"
+        var2: <% $.task2 %>
 """

 PARALLEL_TASKS_COMPLEX_WF = """
@ -136,27 +136,27 @@ wf:
    task1:
      action: std.echo output="Hi"
      publish:
-        greeting: "{$.task1}"
+        greeting: <% $.task1 %>
      on-success:
        - task2

    task2:
      action: std.echo output="Yo"
      publish:
-        greeting: "{$.task2}"
+        greeting: <% $.task2 %>
      on-success:
        - task3

    task3:
      action: std.echo output="Morpheus"
      publish:
-        to: "{$.task3}"
+        to: <% $.task3 %>
      on-success:
        - task4

    task4:
      publish:
-        result: "{$.greeting}, {$.to}! Sincerely, your {$.__env.from}."
+        result: "<% $.greeting %>, <% $.to %>! Your <% $.__env.from %>."
 """


@ -294,7 +294,7 @@ class DataFlowEngineTest(engine_test_base.EngineTestCase):
        self.assertDictEqual({'greeting': 'Yo'}, task2.result)
        self.assertDictEqual({'to': 'Morpheus'}, task3.result)
        self.assertDictEqual(
-            {'result': 'Yo, Morpheus! Sincerely, your Neo.'},
+            {'result': 'Yo, Morpheus! Your Neo.'},
            task4.result
        )

@ -340,9 +340,9 @@ class DataFlowTest(test_base.BaseTest):
        action_output = {'akey': 'adata'}

        publish = {
-            'v': '{$.var}',
-            'e': '{$.__env.ekey}',
-            'a': '{$.task1.akey}'
+            'v': '<% $.var %>',
+            'e': '<% $.__env.ekey %>',
+            'a': '<% $.task1.akey %>'
        }

        task_db = models.Task(name='task1')
@ -375,7 +375,7 @@ class DataFlowTest(test_base.BaseTest):

        Expected to get action error.
        """
-        publish = {'foo': '{$.akey}'}
+        publish = {'foo': '<% $.akey %>'}
        action_output = 'error data'

        task_db = models.Task(name='task1')
--- a/mistral/tests/unit/engine1/test_default_engine.py
+++ b/mistral/tests/unit/engine1/test_default_engine.py
@ -52,12 +52,12 @@ workflows:

    tasks:
      task1:
-        action: std.echo output="{$.param1}"
+        action: std.echo output=<% $.param1 %>
        publish:
-            result: "{$.task1}"
+            result: <% $.task1 %>

      task2:
-        action: std.echo output="{$.param2}"
+        action: std.echo output=<% $.param2 %>
        requires: [task1]

 """
@ -137,7 +137,10 @@ class DefaultEngineTest(base.DbTestCase):
        self.assertDictEqual({'output': 'Hey'}, task_db.input)

    def test_start_workflow_with_adhoc_env(self):
-        wf_input = {'param1': '{$.__env.key1}', 'param2': '{$.__env.key2}'}
+        wf_input = {
+            'param1': '<% $.__env.key1 %>',
+            'param2': '<% $.__env.key2 %>'
+        }
        env = ENVIRONMENT['variables']

        # Start workflow.
@ -155,7 +158,10 @@ class DefaultEngineTest(base.DbTestCase):

    @mock.patch.object(db_api, "get_environment", MOCK_ENVIRONMENT)
    def test_start_workflow_with_saved_env(self):
-        wf_input = {'param1': '{$.__env.key1}', 'param2': '{$.__env.key2}'}
+        wf_input = {
+            'param1': '<% $.__env.key1 %>',
+            'param2': '<% $.__env.key2 %>'
+        }
        env = ENVIRONMENT['variables']

        # Start workflow.
@ -176,7 +182,7 @@ class DefaultEngineTest(base.DbTestCase):
        self.assertRaises(exc.NotFoundException,
                          self.engine.start_workflow,
                          'wb.wf1',
-                          {'param1': '{$.__env.key1}'},
+                          {'param1': '<% $.__env.key1 %>'},
                          env='foo',
                          task_name='task2')

@ -184,7 +190,7 @@ class DefaultEngineTest(base.DbTestCase):
        self.assertRaises(ValueError,
                          self.engine.start_workflow,
                          'wb.wf1',
-                          {'param1': '{$.__env.key1}'},
+                          {'param1': '<% $.__env.key1 %>'},
                          env=True,
                          task_name='task2')

--- a/mistral/tests/unit/engine1/test_direct_workflow.py
+++ b/mistral/tests/unit/engine1/test_direct_workflow.py
@ -203,12 +203,12 @@ class DirectWorkflowEngineTest(base.EngineTestCase):
          tasks:
            task1:
              action: std.echo output="Echo"
-              # publish: {wrong yaql}
+              # publish: <% wrong yaql %>
              on-complete:
                - task2

            task2:
-              action: std.echo output="{wrong yaql}"
+              action: std.echo output=<% wrong yaql %>
        """
        exec_db = self._run_workflow(WORKFLOW_MESSED_YAQL)

@ -222,7 +222,7 @@ class DirectWorkflowEngineTest(base.EngineTestCase):
          type: direct
          tasks:
            task1:
-              action: std.echo output="{wrong(yaql)}"
+              action: std.echo output=<% wrong(yaql) %>
        """
        wf_service.create_workflows(WORKFLOW_MESSED_YAQL_IN_FIRST_TASK)

--- a/mistral/tests/unit/engine1/test_environment.py
+++ b/mistral/tests/unit/engine1/test_environment.py
@ -46,37 +46,37 @@ workflows:
      - param2

    output:
-      final_result: "{$.final_result}"
+      final_result: <% $.final_result %>

    tasks:
      task1:
-        action: std.echo output='{$.param1}'
-        target: "{$.__env.var1}"
+        action: std.echo output=<% $.param1 %>
+        target: <% $.__env.var1 %>
        publish:
-          result1: "{$.task1}"
+          result1: <% $.task1 %>

      task2:
        requires: [task1]
-        action: std.echo output="'{$.result1} & {$.param2}'"
-        target: "{$.__env.var1}"
+        action: std.echo output="'<% $.result1 %> & <% $.param2 %>'"
+        target: <% $.__env.var1 %>
        publish:
-          final_result: "{$.task2}"
+          final_result: <% $.task2 %>

  wf2:
    type: direct

    output:
-      slogan: "{$.slogan}"
+      slogan: <% $.slogan %>

    tasks:
      task1:
        workflow: wf1
        input:
-          param1: "{$.__env.var2}"
-          param2: "{$.__env.var3}"
+          param1: <% $.__env.var2 %>
+          param2: <% $.__env.var3 %>
          task_name: task2
        publish:
-          slogan: "{$.task1.final_result} is a cool {$.__env.var4}!"
+          slogan: "<% $.task1.final_result %> is a cool <% $.__env.var4 %>!"
 """


@ -187,7 +187,7 @@ class SubworkflowsTest(base.EngineTestCase):
        env = {
            'var1': TARGET,
            'var2': 'Bonnie',
-            'var3': '{$.__env.var5}',
+            'var3': '<% $.__env.var5 %>',
            'var4': 'movie',
            'var5': 'Clyde'
        }
--- a/mistral/tests/unit/engine1/test_javascript_action.py
+++ b/mistral/tests/unit/engine1/test_javascript_action.py
@ -53,10 +53,10 @@ workflows:
          # Skip this '$' sign until bug
          # https://bugs.launchpad.net/mistral/+bug/1415886 is resolved.
          # return $['num'] * 10
-          context: "{$}"
+          context: <% $ %>

        publish:
-          result: "{$.task1}"
+          result: <% $.task1 %>

 """

--- a/mistral/tests/unit/engine1/test_join.py
+++ b/mistral/tests/unit/engine1/test_join.py
@ -33,28 +33,28 @@ wf:
  type: direct

  output:
-    result: "{$.result3}"
+    result: <% $.result3 %>

  tasks:
    task1:
      action: std.echo output=1
      publish:
-        result1: "{$.task1}"
+        result1: <% $.task1 %>
      on-complete:
        - task3

    task2:
      action: std.echo output=2
      publish:
-        result2: "{$.task2}"
+        result2: <% $.task2 %>
      on-complete:
        - task3

    task3:
      join: all
-      action: std.echo output="{$.result1},{$.result2}"
+      action: std.echo output="<% $.result1 %>,<% $.result2 %>"
      publish:
-        result3: "{$.task3}"
+        result3: <% $.task3 %>
 """


@ -66,13 +66,13 @@ wf:
  type: direct

  output:
-    result: "{$.result3}"
+    result: <% $.result3 %>

  tasks:
    task1:
      action: std.echo output=1
      publish:
-        result1: "{$.task1}"
+        result1: <% $.task1 %>
      on-complete:
        - task3

@ -83,9 +83,9 @@ wf:

    task3:
      join: all
-      action: std.echo output="{$.result1}-{$.result1}"
+      action: std.echo output="<% $.result1 %>-<% $.result1 %>"
      publish:
-        result3: "{$.task3}"
+        result3: <% $.task3 %>
 """

 WF_FULL_JOIN_WITH_CONDITIONS = """
@ -96,34 +96,34 @@ wf:
  type: direct

  output:
-    result: "{$.result4}"
+    result: <% $.result4 %>

  tasks:
    task1:
      action: std.echo output=1
      publish:
-        result1: "{$.task1}"
+        result1: <% $.task1 %>
      on-complete:
        - task3

    task2:
      action: std.echo output=2
      publish:
-        result2: "{$.task2}"
+        result2: <% $.task2 %>
      on-complete:
-        - task3: "{$.result2 = 11111}"
-        - task4: "{$.result2 = 2}"
+        - task3: <% $.result2 = 11111 %>
+        - task4: <% $.result2 = 2 %>

    task3:
      join: all
-      action: std.echo output="{$.result1}-{$.result1}"
+      action: std.echo output="<% $.result1 %>-<% $.result1 %>"
      publish:
-        result3: "{$.task3}"
+        result3: <% $.task3 %>

    task4:
      action: std.echo output=4
      publish:
-        result4: "{$.task4}"
+        result4: <% $.task4 %>
 """

 WF_PARTIAL_JOIN = """
@ -134,20 +134,20 @@ wf:
  type: direct

  output:
-    result: "{$.result4}"
+    result: <% $.result4 %>

  tasks:
    task1:
      action: std.echo output=1
      publish:
-        result1: "{$.task1}"
+        result1: <% $.task1 %>
      on-complete:
        - task4

    task2:
      action: std.echo output=2
      publish:
-        result2: "{$.task2}"
+        result2: <% $.task2 %>
      on-complete:
        - task4

@ -165,9 +165,9 @@ wf:

    task4:
      join: 2
-      action: std.echo output="{$.result1},{$.result2}"
+      action: std.echo output="<% $.result1 %>,<% $.result2 %>"
      publish:
-        result4: "{$.task4}"
+        result4: <% $.task4 %>
 """

 WF_PARTIAL_JOIN_TRIGGERS_ONCE = """
@ -178,7 +178,7 @@ wf:
  type: direct

  output:
-    result: "{$.result4}"
+    result: <% $.result4 %>

  tasks:
    task1:
@ -211,9 +211,11 @@ wf:

    task5:
      join: 2
-      action: std.echo output="{$.result1},{$.result2},{$.result3},{$.result4}"
+      action: std.echo
+      input:
+        output: <% $.result1 %>,<% $.result2 %>,<% $.result3 %>,<% $.result4 %>
      publish:
-        result5: "{$.task5}"
+        result5: <% $.task5 %>
 """

 WF_DISCRIMINATOR = """
@ -224,7 +226,7 @@ wf:
  type: direct

  output:
-    result: "{$.result4}"
+    result: <% $.result4 %>

  tasks:
    task1:
@ -250,9 +252,9 @@ wf:

    task4:
      join: one
-      action: std.echo output="{$.result1},{$.result2},{$.result3}"
+      action: std.echo output="<% $.result1 %>,<% $.result2 %>,<% $.result3 %>"
      publish:
-        result4: "{$.task4}"
+        result4: <% $.task4 %>
 """


--- a/mistral/tests/unit/engine1/test_noop_task.py
+++ b/mistral/tests/unit/engine1/test_noop_task.py
@ -37,20 +37,20 @@ wf:
    - num2

  output:
-    result: "{$.result4},{$.result5}"
+    result: "<% $.result4 %>,<% $.result5 %>"

  tasks:
    task1:
-      action: std.echo output={$.num1}
+      action: std.echo output=<% $.num1 %>
      publish:
-        result1: "{$.task1}"
+        result1: <% $.task1 %>
      on-complete:
        - task3

    task2:
-      action: std.echo output={$.num2}
+      action: std.echo output=<% $.num2 %>
      publish:
-        result2: "{$.task2}"
+        result2: <% $.task2 %>
      on-complete:
        - task3

@ -60,18 +60,18 @@ wf:
        task and serves just a decision point in the workflow.
      join: all
      on-complete:
-        - task4: "{$.num1 + $.num2 = 2}"
-        - task5: "{$.num1 + $.num2 = 3}"
+        - task4: <% $.num1 + $.num2 = 2 %>
+        - task5: <% $.num1 + $.num2 = 3 %>

    task4:
      action: std.echo output=4
      publish:
-        result4: "{$.task4}"
+        result4: <% $.task4 %>

    task5:
      action: std.echo output=5
      publish:
-        result5: "{$.task5}"
+        result5: <% $.task5 %>
 """


--- a/mistral/tests/unit/engine1/test_policies.py
+++ b/mistral/tests/unit/engine1/test_policies.py
@ -48,7 +48,7 @@ workflows:
          retry:
            count: 5
            delay: 10
-            break-on: "{$.my_val = 10}"
+            break-on: <% $.my_val = 10 %>
 """


@ -133,7 +133,7 @@ workflows:
          retry:
            count: 3
            delay: 1
-            break-on: "{$.my_val = 10}"
+            break-on: <% $.my_val = 10 %>
 """


@ -248,7 +248,7 @@ class PoliciesTest(base.EngineTestCase):

        self.assertIsInstance(p, policies.RetryPolicy)
        self.assertEqual(5, p.count)
-        self.assertEqual('{$.my_val = 10}', p.break_on)
+        self.assertEqual('<% $.my_val = 10 %>', p.break_on)

        p = self._assert_single_item(arr, delay=7)

--- a/mistral/tests/unit/engine1/test_race_condition.py
+++ b/mistral/tests/unit/engine1/test_race_condition.py
@ -43,13 +43,13 @@ wf:
    method. And we need to check that engine handles this situation.

  output:
-    result: "{$.result}"
+    result: <% $.result %>

  tasks:
    task1:
      action: std.block
      publish:
-        result: "{$.task1}"
+        result: <% $.task1 %>
 """

 WF_SHORT_ACTION = """
@ -73,13 +73,13 @@ wf:
    methods ends.

  output:
-    result: "{$.result}"
+    result: <% $.result %>

  tasks:
    task1:
      action: std.echo output=1
      publish:
-        result1: "{$.task1}"
+        result1: <% $.task1 %>

    task2:
      action: std.block
--- a/mistral/tests/unit/engine1/test_reverse_workflow.py
+++ b/mistral/tests/unit/engine1/test_reverse_workflow.py
@ -42,14 +42,14 @@ workflows:

    tasks:
      task1:
-        action: std.echo output='{$.param1}'
+        action: std.echo output=<% $.param1 %>
        publish:
-          result1: "{$.task1}"
+          result1: <% $.task1 %>

      task2:
-        action: std.echo output="{$.result1} & {$.param2}"
+        action: std.echo output="<% $.result1 %> & <% $.param2 %>"
        publish:
-          result2: "{$.task2}"
+          result2: <% $.task2 %>
        requires: [task1]
 """

--- a/mistral/tests/unit/engine1/test_subworkflows.py
+++ b/mistral/tests/unit/engine1/test_subworkflows.py
@ -44,30 +44,30 @@ workflows:
      - param1
      - param2
    output:
-      final_result: "{$.final_result}"
+      final_result: <% $.final_result %>

    tasks:
      task1:
-        action: std.echo output='{$.param1}'
+        action: std.echo output=<% $.param1 %>
        publish:
-          result1: "{$.task1}"
+          result1: <% $.task1 %>

      task2:
-        action: std.echo output="'{$.param1} & {$.param2}'"
+        action: std.echo output="'<% $.param1 %> & <% $.param2 %>'"
        publish:
-          final_result: "{$.task2}"
+          final_result: <% $.task2 %>
        requires: [task1]

  wf2:
    type: direct
    output:
-      slogan: "{$.slogan}"
+      slogan: <% $.slogan %>

    tasks:
      task1:
        workflow: wf1 param1='Bonnie' param2='Clyde' task_name='task2'
        publish:
-          slogan: "{$.task1.final_result} is a cool movie!"
+          slogan: "<% $.task1.final_result %> is a cool movie!"
 """


--- a/mistral/tests/unit/engine1/test_with_items.py
+++ b/mistral/tests/unit/engine1/test_with_items.py
@ -45,10 +45,10 @@ workflows:

    tasks:
      task1:
-        with-items: name_info in {$.names_info}
-        action: std.echo output={$.name_info.name}
+        with-items: name_info in <% $.names_info %>
+        action: std.echo output=<% $.name_info.name %>
        publish:
-          result: "{$.task1}"
+          result: <% $.task1 %>

 """

@ -68,10 +68,10 @@ workflows:

    tasks:
      task1:
-        with-items: name_info in {$.names_info}
-        action: std.echo output="{$.greeting}, {$.name_info.name}!"
+        with-items: name_info in <% $.names_info %>
+        action: std.echo output="<% $.greeting %>, <% $.name_info.name %>!"
        publish:
-          result: "{$.task1}"
+          result: <% $.task1 %>
 """


@ -92,11 +92,11 @@ workflows:
    tasks:
      task1:
        with-items:
-          - itemX in {$.arrayI}
-          - itemY in {$.arrayJ}
-        action: std.echo output="{$.itemX} {$.itemY}"
+          - itemX in <% $.arrayI %>
+          - itemY in <% $.arrayJ %>
+        action: std.echo output="<% $.itemX %> <% $.itemY %>"
        publish:
-          result: "{$.task1}"
+          result: <% $.task1 %>

 """

@ -113,10 +113,10 @@ workflows:
      - links
    tasks:
      task1:
-        with-items: link in {$.links}
-        action: std.mistral_http url={$.link}
+        with-items: link in <% $.links %>
+        action: std.mistral_http url=<% $.link %>
        publish:
-          result: "{$.task1}"
+          result: <% $.task1 %>
 """


--- a/mistral/tests/unit/test_expressions.py
+++ b/mistral/tests/unit/test_expressions.py
@ -117,11 +117,11 @@ class InlineYAQLEvaluatorTest(base.BaseTest):

    def test_multiple_placeholders(self):
        expr_str = """
-            Statistics for tenant "{$.project_id}"
+            Statistics for tenant "<% $.project_id %>"

-            Number of virtual machines: {$.vm_count}
-            Number of active virtual machines: {$.active_vm_count}
-            Number of networks: {$.net_count}
+            Number of virtual machines: <% $.vm_count %>
+            Number of active virtual machines: <% $.active_vm_count %>
+            Number of networks: <% $.net_count %>

            -- Sincerely, Mistral Team.
        """
@ -168,19 +168,19 @@ class ExpressionsTest(base.BaseTest):
        }

        test_cases = [
-            ('{$.a + $.b * $.c}', 7),
-            ('{($.a + $.b) * $.c}', 9),
-            ('{$.d and $.e}', False),
-            ('{$.f > $.g}', True),
-            ('{$.h.length() >= 5}', True),
-            ('{$.h.length() >= $.b + $.c}', True),
-            ('{100 in $.h}', False),
-            ('{$.a in $.h}', True),
-            ('{''OpenStack'' in $.i}', True),
-            ('Hello, {$.j}!', 'Hello, World!'),
-            ('{$.k} is {$.l}!', 'Mistral is awesome!'),
-            ('This is {$.m}.', 'This is the way we roll.'),
-            ('{1 + 1 = 3}', False)
+            ('<% $.a + $.b * $.c %>', 7),
+            ('<%($.a + $.b) * $.c %>', 9),
+            ('<% $.d and $.e %>', False),
+            ('<% $.f > $.g %>', True),
+            ('<% $.h.length() >= 5 %>', True),
+            ('<% $.h.length() >= $.b + $.c %>', True),
+            ('<% 100 in $.h %>', False),
+            ('<% $.a in $.h%>', True),
+            ('<% ''OpenStack'' in $.i %>', True),
+            ('Hello, <% $.j %>!', 'Hello, World!'),
+            ('<% $.k %> is <% $.l %>!', 'Mistral is awesome!'),
+            ('This is <% $.m %>.', 'This is the way we roll.'),
+            ('<% 1 + 1 = 3 %>', False)
        ]

        for expression, expected in test_cases:
@ -192,7 +192,7 @@ class ExpressionsTest(base.BaseTest):
        task_spec_dict = {
            'parameters': {
                'p1': 'My string',
-                'p2': '{$.param2}',
+                'p2': '<% $.param2 %>',
                'p3': ''
            },
            'publish': {
@ -228,16 +228,16 @@ class ExpressionsTest(base.BaseTest):
        data = {
            "parameters": {
                "parameter1": {
-                    "name1": "{$.auth_token}",
+                    "name1": "<% $.auth_token %>",
                    "name2": "val_name2"
                },
                "param2": [
                    "var1",
                    "var2",
-                    "/servers/{$.project_id}/bla"
+                    "/servers/<% $.project_id %>/bla"
                ]
            },
-            "token": "{$.auth_token}"
+            "token": "<% $.auth_token %>"
        }

        applied = expr.evaluate_recursively(data, context)
@ -264,7 +264,8 @@ class ExpressionsTest(base.BaseTest):
            'verbose': True,
            '__actions': {
                'std.sql': {
-                    'conn': 'mysql://admin:secrete@{$.__env.host}/{$.__env.db}'
+                    'conn': 'mysql://admin:secrete@<% $.__env.host %>'
+                            '/<% $.__env.db %>'
                }
            }
        }
--- a/mistral/tests/unit/workbook/v2/test_dsl_specs_v2.py
+++ b/mistral/tests/unit/workbook/v2/test_dsl_specs_v2.py
@ -33,14 +33,14 @@ actions:
    tags: [test, v2]
    base: std.echo
    base-input:
-      output: Hello {$.name}!
-    output: "{$}"
+      output: Hello <% $.name %>!
+    output: <% $ %>

  action2:
    description: This is a test ad-hoc action with base params
    tags: [test, v2]
    base: std.echo output="Echo output"
-    output: "{$}"
+    output: <% $ %>

 workflows:
  wf1:
@ -54,19 +54,19 @@ workflows:
    tasks:
      task1:
        description: This is a test task
-        action: action1 name="{$.name}"
+        action: action1 name=<% $.name %>
        policies:
          wait-before: 2
          wait-after: 5
          retry:
            count: 10
            delay: 30
-            break-on: "{$.my_val = 10}"
+            break-on: <% $.my_val = 10 %>
          concurrency: 3

      task2:
        requires: [task1]
-        action: std.echo output="Thanks {$.name}!"
+        action: std.echo output="Thanks <% $.name %>!"

  wf2:
    tags: [test, v2]
@ -77,9 +77,9 @@ workflows:
        retry:
          count: 10
          delay: 30
-          break-on: "{$.my_val = 10}"
+          break-on: <% $.my_val = 10 %>
      on-error:
-        - fail: "{$.my_val = 0}"
+        - fail: <% $.my_val = 0 %>
      on-success:
        - pause
      on-complete:
@ -89,11 +89,11 @@ workflows:
      task3:
        workflow: wf1 name="John Doe" age=32 param1=null param2=false
        on-error:
-          - task4: "{$.my_val = 1}"
+          - task4: <% $.my_val = 1 %>
        on-success:
-          - task5: "{$.my_val = 2}"
+          - task5: <% $.my_val = 2 %>
        on-complete:
-          - task6: "{$.my_val = 3}"
+          - task6: <% $.my_val = 3 %>

      task4:
        action: std.echo output="Task 4 echo"
@ -105,7 +105,7 @@ workflows:
        action: std.echo output="Task 6 echo"

      task7:
-        with-items: vm_info in {$.vms}
+        with-items: vm_info in <% $.vms %>
        workflow: wf2 is_true=true object_list=[1, null, "str"] is_string="50"
        on-complete:
          - task9
@ -113,9 +113,9 @@ workflows:

      task8:
        with-items:
-         - itemX in {$.arrayI}
-         - itemY in {$.arrayJ}
-        workflow: wf2 expr_list=["{$.value}", "{$.key}"] expr={$.value}
+         - itemX in <% $.arrayI %>
+         - itemY in <% $.arrayJ %>
+        workflow: wf2 expr_list=["<% $.v %>", "<% $.k %>"] expr=<% $.value %>
        target: nova
        on-complete:
          - task9
@ -134,7 +134,7 @@ workflows:
        action: std.echo output="Task 11 echo"

      task12:
-        action: std.http url="http://site.com?q={$.query}" params=""
+        action: std.http url="http://site.com?q=<% $.query %>" params=""

      task13:
        description: No-op task
@ -269,11 +269,11 @@ class DSLv2ModelTest(base.BaseTest):
        self.assertListEqual(['test', 'v2'], action_spec.get_tags())
        self.assertEqual('std.echo', action_spec.get_base())
        self.assertDictEqual(
-            {'output': 'Hello {$.name}!'},
+            {'output': 'Hello <% $.name %>!'},
            action_spec.get_base_input()
        )
        self.assertListEqual([], action_spec.get_input())
-        self.assertEqual('{$}', action_spec.get_output())
+        self.assertEqual('<% $ %>', action_spec.get_output())

        # Workflows.

@ -300,7 +300,7 @@ class DSLv2ModelTest(base.BaseTest):
        self.assertEqual('task1', task1_spec.get_name())
        self.assertEqual('This is a test task', task1_spec.get_description())
        self.assertEqual('action1', task1_spec.get_action_name())
-        self.assertEqual({'name': '{$.name}'}, task1_spec.get_input())
+        self.assertEqual({'name': '<% $.name %>'}, task1_spec.get_input())

        policies = task1_spec.get_policies()

@ -312,7 +312,7 @@ class DSLv2ModelTest(base.BaseTest):

        self.assertEqual(10, retry_spec.get_count())
        self.assertEqual(30, retry_spec.get_delay())
-        self.assertEqual('{$.my_val = 10}', retry_spec.get_break_on())
+        self.assertEqual('<% $.my_val = 10 %>', retry_spec.get_break_on())

        task2_spec = wf1_spec.get_tasks().get('task2')

@ -322,7 +322,7 @@ class DSLv2ModelTest(base.BaseTest):
        self.assertEqual('std.echo', task2_spec.get_action_name())
        self.assertIsNone(task2_spec.get_workflow_name())
        self.assertEqual(
-            {'output': 'Thanks {$.name}!'},
+            {'output': 'Thanks <% $.name %>!'},
            task2_spec.get_input()
        )

@ -337,7 +337,7 @@ class DSLv2ModelTest(base.BaseTest):
        task_defaults_spec = wf2_spec.get_task_defaults()

        self.assertListEqual(
-            [('fail', '{$.my_val = 0}')],
+            [('fail', '<% $.my_val = 0 %>')],
            task_defaults_spec.get_on_error()
        )
        self.assertListEqual(
@ -366,15 +366,15 @@ class DSLv2ModelTest(base.BaseTest):
            task3_spec.get_input()
        )
        self.assertListEqual(
-            [('task4', '{$.my_val = 1}')],
+            [('task4', '<% $.my_val = 1 %>')],
            task3_spec.get_on_error()
        )
        self.assertListEqual(
-            [('task5', '{$.my_val = 2}')],
+            [('task5', '<% $.my_val = 2 %>')],
            task3_spec.get_on_success()
        )
        self.assertListEqual(
-            [('task6', '{$.my_val = 3}')],
+            [('task6', '<% $.my_val = 3 %>')],
            task3_spec.get_on_complete()
        )

@ -390,21 +390,21 @@ class DSLv2ModelTest(base.BaseTest):
        )

        self.assertEqual(
-            {'vm_info': '{$.vms}'},
+            {'vm_info': '<% $.vms %>'},
            task7_spec.get_with_items()
        )

        task8_spec = wf2_spec.get_tasks().get('task8')

        self.assertEqual(
-            {"itemX": '{$.arrayI}', "itemY": '{$.arrayJ}'},
+            {"itemX": '<% $.arrayI %>', "itemY": '<% $.arrayJ %>'},
            task8_spec.get_with_items()
        )

        self.assertEqual(
            {
-                'expr_list': ['{$.value}', '{$.key}'],
-                'expr': '{$.value}',
+                'expr_list': ['<% $.v %>', '<% $.k %>'],
+                'expr': '<% $.value %>',
            },
            task8_spec.get_input()
        )
@ -426,7 +426,7 @@ class DSLv2ModelTest(base.BaseTest):
        task12_spec = wf2_spec.get_tasks().get('task12')

        self.assertDictEqual(
-            {'url': 'http://site.com?q={$.query}', 'params': ''},
+            {'url': 'http://site.com?q=<% $.query %>', 'params': ''},
            task12_spec.get_input()
        )

--- a/mistral/tests/unit/workflow/test_direct_workflow.py
+++ b/mistral/tests/unit/workflow/test_direct_workflow.py
@ -38,10 +38,10 @@ workflows:
      task1:
        action: std.echo output="Hey"
        publish:
-          res1: "{$.task1}"
+          res1: <% $.task1 %>
        on-complete:
-          - task2: "{$.res1 = 'Hey'}"
-          - task3: "{$.res1 = 'Not Hey'}"
+          - task2: <% $.res1 = 'Hey' %>
+          - task3: <% $.res1 = 'Not Hey' %>

      task2:
        action: std.echo output="Hi"
--- a/mistral/tests/unit/workflow/test_with_items.py
+++ b/mistral/tests/unit/workflow/test_with_items.py
@ -27,10 +27,10 @@ TASK_DICT = {
    'version': '2.0',
    'action': 'std.echo',
    'with-items': [
-        'item in {$.array}'
+        'item in <% $.array %>'
    ],
    'input': {
-        'array': '{$.my_array}'
+        'array': '<% $.my_array %>'
    }
 }

@ -45,7 +45,7 @@ TASK_DB = models.Task(
 class WithItemsCalculationsTest(base.BaseTest):
    def test_calculate_output_with_key(self):
        task_dict = TASK_DICT.copy()
-        task_dict['publish'] = {'result': '{$.task1}'}
+        task_dict['publish'] = {'result': '<% $.task1 %>'}

        task_spec = tasks.TaskSpec(task_dict)

--- a/mistral/workbook/base.py
+++ b/mistral/workbook/base.py
@ -18,11 +18,12 @@ import re
 import six

 from mistral import exceptions as exc
+from mistral import expressions as expr


 CMD_PTRN = re.compile("^[\w\.]+[^=\s\"]*")

-ALL_IN_BRACES = "\{[^}]*\}\s*"
+INLINE_YAQL = expr.INLINE_YAQL_REGEXP
 _ALL_IN_BRACKETS = "\[.*\]\s*"
 _ALL_IN_QUOTES = "\"[^\"]*\"\s*"
 _ALL_IN_APOSTROPHES = "'[^']*'\s*"
@ -32,7 +33,7 @@ _FALSE = "false"
 _NULL = "null"

 ALL = (
-    _ALL_IN_QUOTES, _ALL_IN_APOSTROPHES, ALL_IN_BRACES,
+    _ALL_IN_QUOTES, _ALL_IN_APOSTROPHES, INLINE_YAQL,
    _ALL_IN_BRACKETS, _TRUE, _FALSE, _NULL, _DIGITS
 )

--- a/mistral/workbook/v2/tasks.py
+++ b/mistral/workbook/v2/tasks.py
@ -23,7 +23,7 @@ from mistral.workbook.v2 import task_policies


 WITH_ITEMS_PTRN = re.compile(
-    "\s*([\w\d_\-]+)\s*in\s*(\[.+\]|%s)" % base.ALL_IN_BRACES
+    "\s*([\w\d_\-]+)\s*in\s*(\[.+\]|%s)" % base.INLINE_YAQL
 )


@ -95,7 +95,7 @@ class TaskSpec(base.BaseSpec):

            if not match:
                msg = ("Wrong format of 'with-items' property. Please use "
-                       "format 'var in {[some, list] | {$.array} }: "
+                       "format 'var in {[some, list] | <%% $.array %%> }: "
                       "%s" % self._data)
                raise exc.InvalidModelException(msg)

--- a/mistral/workflow/with_items.py
+++ b/mistral/workflow/with_items.py
@ -151,8 +151,8 @@ def calc_input(with_items_input):
    Example:
      DSL:
        with_items:
-          - itemX in {$.arrayI}
-          - itemY in {$.arrayJ}
+          - itemX in <% $.arrayI %>
+          - itemY in <% $.arrayJ %>

      Assume arrayI = [1, 2], arrayJ = ['a', 'b'].
      with_items_input = {