Write script rules

A script rule adds steps and checkpoints to a plan by running a Jython script that calculates which steps and checkpoints to add.

important

The script in a script rule runs during the planning phase only. The purpose of the script is to provide steps for the final plan to execute, not to take deployment actions. Script rules do not interact with the Deploy execution phase, although some of the steps executed in that phase may involve executing scripts, such as a jython step.

Define steps in script rules

A script rule uses the following format in xl-rules.xml:

• A rule tag with name and scope attributes, both of which are required.
• An optional conditions tag with:
  • One or more type tags that identify the UDM types that the rule is restricted to. type is required if the scope is deployed, otherwise, you must omit it. The UDM type name must refer to a deployed type and not a deployable, container, or other UDM type.
  • One or more operation tags that identify the operations that the rule is restricted to. The operation can be CREATE, MODIFY, DESTROY, or NOOP. operation is required if the scope is deployed, otherwise, you must omit it.
  • An optional expression tag with an expression in Jython that defines a condition upon which the rule will be triggered. This tag is optional for all scopes. If you specify an expression, it must evaluate to a Boolean value.
• A planning-script-path child tag that identifies a script file that is available on the class path, in the XL_DEPLOY_SERVER_HOME/ext/ directory.

Every script is run in isolation, you cannot pass values directly from one script to another.

Sample script rule: Successfully created artifact

This is an example of a script that is executed for every deployed that is involved in the deployment. The step of type noop will only be added for new deployeds (operation is CREATE) that derive from the type udm.BaseDeployedArtifact, as defined by the type element. Creating a step is done through the factory object steps. Addition of the step is performed through context, which represents the planning context and not the execution context.

<rules xmlns="http://www.xebialabs.com/deploy/rules">
    <rule name="SuccessBaseDeployedArtifact" scope="deployed">
        <conditions>
            <type>udm.BaseDeployedArtifact</type>
            <operation>CREATE</operation>
        </conditions>
        <planning-script-path>planning/SuccessBaseDeployedArtifact.py</planning-script-path>
    </rule>

Where planning/SuccessBaseDeployedArtifact.py, which is stored in the XL_DEPLOY_SERVER_HOME/ext/ directory, has following content:

step = steps.noop(description = "A dummy step to indicate that some new artifact was created on the target environment", order = 100)
context.addStep(step)