Rollback Strategies in ServiceNow

Imagine a child playing with building blocks to construct a tower. Things don't always go as planned—sometimes the tower wobbles or a block is placed incorrectly. To fix it, the child needs strategies to get things back on track. Similarly, ServiceNow developers need methods to roll back changes when something goes wrong.

1. Transaction Management: "Undo the Move"

When the child places a block and notices the tower is unstable, they decide not to add more blocks until they fix the problem.

• gs.beginTransaction() (Start building carefully): The child says, "I’ll try adding this block carefully, but I’ll watch closely to see if it works."
• gs.rollback() (Undo the move): If the tower starts wobbling, the child removes the block they just added and tries again.

This method ensures the tower doesn’t fall apart due to a bad move.

Example:

The child is stacking blocks and adds a new one, thinking it’ll fit perfectly. They test it and realize it's unstable. They carefully remove the block to keep the rest of the tower safe.

"Success is stumbling from failure to failure with no loss of enthusiasm." – Winston Churchill

2. Utilizing Update Sets: "Back to the Original Design"

Imagine the child is experimenting with decorating the tower. They add fancy decorations, but then the tower looks too cluttered. Thankfully, they have a picture of their original tower.

• The child looks at the picture and says, "Let’s go back to how it looked before the decorations."
• In ServiceNow, this is like using Update Sets to revert unwanted changes. The "Back Out" option lets you return to the earlier version of the tower.

"Sometimes you have to take a step back to move forward." – Erika Taylor

3. Scoped Applications and Source Control: "Use the Blueprint"

Now, think of the child following a blueprint (a step-by-step guide) to build the tower. Every time they make progress, they take a picture of their work. If something goes wrong later, they just look at an earlier picture and rebuild from there.

• Source Control in ServiceNow Studio is like these pictures. If a block doesn't fit or causes trouble, the child simply goes back to the last picture where everything was fine and starts again.

"Planning is bringing the future into the present so that you can do something about it now." – Alan Lakein

Best Practices for Rollbacks: Play Smart

To avoid repeating mistakes, the child follows these rules:

1. Frequent Snapshots (Backups): Take lots of pictures of the tower as it grows.
2. Blueprints (Versioning): Keep the step-by-step instructions handy for tracing progress.
3. Test Before Adding (Testing): Try new decorations on a separate mini-tower before adding them to the big one.
4. Write It Down (Documentation): Keep a journal of what worked and what didn’t, so they know for next time.

"A stitch in time saves nine." – Proverb