Commit Script Overview

Commit scripts run each time a new candidate configuration is committed and inspect the configuration. If a candidate configuration does not adhere to your design rules, a commit script can instruct the Services Router to perform various actions, including the following:

• Generate custom warning messages, system log messages, or error messages.

  If error messages are generated, the commit operation fails and the candidate configuration remains unchanged.

• Change the configuration in accordance with your rules and then proceed with the commit operation.

Consider the following examples of actions you can perform with commit scripts:

• Run a basic sanity test. Ensure that the [edit interfaces] and [edit protocols] hierarchies have not been accidentally deleted.
• Check configuration consistency. Ensure that every T1 interface configured at the [edit interfaces] hierarchy level is also configured at the [edit protocols rip] hierarchy level.
• Enforce network design rules. For example, suppose your network design requires every interface on which the International Organization for Standardization (ISO) family of protocols is enabled to also have Multiprotocol Label Switching (MPLS) enabled. At commit time, a commit script inspects the configuration and issues an error if this requirement is not met. This error causes the commit operation to fail and forces the user to update the configuration to comply.

  Instead of an error, the commit script can issue a warning about the configuration problem and then automatically correct it, by changing the configuration to enable MPLS on all interfaces. A system log message can also be generated indicating that corrective action was taken.

The scripting language you use for writing commit scripts is Extensible Stylesheet Language Transformations (XSLT). XSLT commit scripts are based on JUNOScript Extensible Markup Language (XML).