Automating Junos Administration

Chapter 7. Event Scripts and Event Policies

In Chapter 6, we discussed the way you can use op and event scripts to customize your Junos device. As we noted in that chapter, there are many similarities between op and event scripts. However, there are also some considerations unique to event scripts. In this chapter, we will build on the material we covered in Chapter 6 as we discuss the ways you can use event scripts to customize your Junos device.

In addition, we will consider event policies. The system uses event policies to decide when to execute event scripts. In fact, it is possible to carry out some automatic event responses directly in an event policy without executing an event script.

Because this chapter builds on the information found in Chapter 6, it may be helpful to review that chapter if you have not already done so. In particular, you should review “Operational and Configuration State”, “Some Useful Tools for Op and Event Scripts”, and “Debugging Op and Event Scripts”.

Overview of Event Script Operation

As we mentioned in “Overview of Op Script Operation”, op and event scripts share some similarities with each other and with commit scripts. Recall that all three of these scripts work on XML documents: they receive an XML input document, process it, and produce an XML output document. Because of the nature of this work (an XML transformation), these scripts are written in XSLT or SLAX. We suggest that you use SLAX for writing these scripts.

While the operation of event scripts ...