Summary

Synopsis

Prior to InstallAnywhere 2010 there was no rollback functionality built into InstallAnywhere. This meant that if an installation was cancelled before the Install sequence was complete, any payload files that had been delivered and any changes made by actions that had executed remained on the target machine. In order to clean up a cancelled installation, it was necessary to write a custom action which implemented the RollbackHandler interface and ensure that this action was the first action in the Install sequence. This custom action's rollBack() method was then called when an installation was cancelled and was responsible for cleaning up any files installed or changes that had been made to the target machine.

InstallAnywhere 2010 has introduced a built in Rollback functionality to make this process more simple, straightforward, and less time consuming for the setup developer. The requirement of writing a custom action that handles the rollback no longer exists. The setup developer can enable Rollback with one simple setting in the project file. The generated installer will then keep track of the changes made to the target machine as the installation progresses and, if the installer is cancelled or a Fatal error is generated, automatically roll these changes back leaving the target machine in the state it was prior to launching the installer.

Discussion

Design Time Considerations

Enabling Rollback

In order to enable rollback in a project navigate to Project > Advanced in the Designer. Under the Rollback Settings heading, select the checkbox labeled ?Enable Rollback.? This will enable Rollback for this project.

Configuring Rollback Behavior

The first option, ?If rollback is triggered at install time, uninstall this action/resource,? is used to determine the behavior for this specific action in the case that the installation is cancelled by the end user or a Fatal error is generated. If this option is selected, this action will be uninstalled during a rollback. If this option is not selected, this action will not be uninstalled during a rollback.

Trigger Rollback Action

There may be times where it is necessary to actually trigger a Rollback without the user cancelling the installation or a fatal error being generated. A new built in Trigger Rollback Action has been included in order to accomplish this. When this action executes, a Rollback will be triggered and the installation rolled back. This action is only available in the Install sequence.

Runtime Behavior

GUI Mode

If the installer has been configured to generate a log file (Project > Info > Installation Log), a message will be written to the log file when the installation has been rolled back.

When the Trigger Rollback Action is used, the following is written to the log file:

Trigger Rollback:

Error occurred while installing the following Action, hence rolling back the installation....!

Action Name: Trigger Rollback Action

Action Description: Trigger Rollback Action

Error Details as below:

This action rolls back the Installation.

When the user cancels the installation, the following is written to the log file:

INSTALLATION WAS CANCELLED BY USER DURING INSTALLATION

Additional Information

As mentioned previously, installers built with InstallAnywhere versions prior to InstallAnywhere 2010 had to use a Custom Action that implemented the RollbackHandler Interface in order to rollback an incomplete installation. When a project using such an action is migrated to InstallAnywhere 2010 or later, if the Enable Rollback option is enabled, the Custom Action which implements the RollbackHandler will never be called. If this action needs to be called during an incomplete installation, the Enable Rollback option must not be selected.

Please see the following HelpNet pages regarding Rollback for additional information:

Rollback Settings

Configuring Installaton Rollback Behavior

Trigger Rollback