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Using a Specific Version of Pack Content When Running an Action


This functionality is available in EWC >= 2.7.0 and requires git >= 2.5 to be installed. Using the latest stable version of git is recommended.

If you are using Ubuntu 14.04, the latest stable version of git can be installed directly from the official git ppa. For RHEL / CentOS, the latest version can be found in the IUS repos.

By default, when running an execution for an action from a pack on disk which is a git repository, EWC will use the currently checked out git revision of the pack content. That is the version you have specified when installing the pack using st2 pack install <pack name>[=pack version].

If you don’t explicitly specify a version, the latest stable version will be installed and used for the action executions.

EWC v2.7.0 introduced a new content_version runner parameter for the local and Python runner actions.

When running an action, users can specify this parameter, which can be a git revision hash, tag or a branch. This will cause EWC to use action content from that git revision.

This is useful in many scenarios, such as when performing consistent zero downtime pack upgrades and you want to use different version of the action content for different pack executions (e.g. for some executions you want to use the older version v2.2.0 and for other executions you want to use version v2.3.0 which has just been deployed).

Example Usage

The easiest way to demonstrate this functionality is using a pack which was built for purposes of demonstrating and testing it -

This pack contains 3 different actions which sole purpose is to print out the current pack version. The pack itself contains 4 different versions / tags (v0.1.0, v0.2.0, v0.3.0, v0.4.0). In a standard EWC pack git repository layout each pack version should have a corresponding git tag.

Installing the pack

st2 pack install

vagrant@local$ st2 pack install

    [ succeeded ] download pack
    [ succeeded ] make a prerun
    [ succeeded ] install pack dependencies
    [ succeeded ] register pack

| Property    | Value                                                       |
| name        | test_content_version                                        |
| description | StackStorm pack for testing "content_version" functionality |
| version     | 0.4.0                                                       |
| author      | st2-dev                                                     |

Running the latest installed and checked out pack version (v0.4.0)

By default, if no version if specified, the latest installed and checked out version is used. This is the same behavior as before:

vagrant@local$ st2 run test_content_version.python_runner_print_version

id: 5ad0ce8b0640fd27f7b97845
status: succeeded
parameters: None
  exit_code: 0
  result: v0.4.0
  stderr: ''
  stdout: 'v0.4.0

Running a specific version

In this case we specify that we want to use git tag v0.2.0 which matches the same pack version:

vagrant@local$ st2 run test_content_version.python_runner_print_version content_version=v0.2.0

id: 5ad0cee40640fd27f7b97848
status: succeeded
  content_version: v0.2.0
  exit_code: 0
  result: v0.2.0
  stderr: ''
  stdout: 'v0.2.0


Right now only the content (code, metadata) inside the pack directory which is a git repository is versioned. This means that for Python runner actions, virtual environments and requirements are not versioned and the latest version of the virtual environments which is installed is always used when running an action.