- play_arrow Overview
- play_arrow Junos Automation Scripts Overview
- play_arrow Junos XML Management Protocol and Junos XML API Overview
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- play_arrow Automation Scripting Using SLAX
- play_arrow SLAX Overview
- SLAX Overview
- SLAX Syntax Rules Overview
- SLAX Elements and Element Attributes Overview
- SLAX Elements as Function Arguments
- Understanding SLAX Default Namespaces
- XPath Expressions Overview for SLAX
- SLAX Templates Overview
- SLAX Functions Overview
- SLAX Parameters Overview
- SLAX Variables Overview
- SLAX Statements Overview
- XSLT Elements Without SLAX Equivalents
- SLAX Operators
- play_arrow SLAX Statements
- append
- apply-imports
- apply-templates
- attribute
- attribute-set
- call
- copy-node
- copy-of
- decimal-format
- element
- else
- else if
- expr
- fallback
- for
- for-each
- function
- if
- import
- key
- match
- message
- mode
- mvar
- number
- output-method
- param
- preserve-space
- priority
- processing-instruction
- result
- set
- sort
- strip-space
- template
- terminate
- trace
- uexpr
- use-attribute-sets
- var
- version
- while
- with
- play_arrow The libslax Distribution for Automation Scripting
- libslax Distribution Overview
- libslax Library and Extension Libraries Overview
- Download and Install the libslax Distribution
- libslax Default Extension Libraries: bit, curl, db, os, and xutil
- Understanding the SLAX Processor (slaxproc)
- How to Use the SLAX Processor (slaxproc)
- SLAX Debugger, Profiler, and callflow
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- play_arrow Automation Scripting Using Python
- play_arrow Python Overview
- Understanding Python Automation Scripts for Junos Devices
- Requirements for Executing Python Automation Scripts on Junos Devices
- Overview of Python Modules on Junos Devices
- How to Use Python Interactive Mode on Devices Running Junos OS
- How to Use the psutil Module to Retrieve Process and System Information on Devices Running Junos OS
- How to Use the Requests Library for Python on Devices Running Junos OS
- IPv6 Support in Python Automation Scripts
- How to Specify the Routing Instance in Python 3 Applications on Devices Running Junos OS Evolved
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- play_arrow Automation Script Input
- play_arrow Global Parameters in Automation Scripts
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- play_arrow Extension Functions and Named Templates for Automation Scripts
- play_arrow Extension Functions for Automation Scripting
- play_arrow Extension Functions in the jcs and slax Namespaces
- base64-decode() Function (SLAX)
- base64-encode() Function (SLAX)
- break-lines() Function (SLAX and XSLT)
- close() Function (SLAX and XSLT)
- dampen() Function (Python, SLAX, and XSLT)
- document() Function (SLAX)
- emit_error() Function (Python)
- emit_snmp_attributes Function (Python)
- emit_warning() Function (Python)
- empty() Function (SLAX and XSLT)
- evaluate() Function (SLAX)
- execute() Function (SLAX and XSLT)
- first-of() Function (SLAX and XSLT)
- get-command() Function (SLAX)
- get-hello() Function (SLAX and XSLT)
- get-input() Function (SLAX and XSLT) and get_input() (Python)
- get-protocol() Function (SLAX and XSLT)
- get-secret() Function (SLAX and XSLT) and get_secret() (Python)
- get_snmp_action() Function (Python)
- get_snmp_oid() Function (Python)
- hostname() Function (Python, SLAX, and XSLT)
- invoke() Function (SLAX and XSLT)
- open() Function (SLAX and XSLT)
- output() Function (Python, SLAX, and XSLT)
- parse-ip() Function (SLAX and XSLT) and parse_ip() (Python)
- printf() Function (Python, SLAX, and XSLT)
- progress() Function (Python, SLAX, and XSLT)
- regex() Function (SLAX and XSLT)
- set_routing_instance() Function (Python)
- sleep() Function (SLAX and XSLT)
- split() Function (SLAX and XSLT)
- sysctl() Function (Python, SLAX, and XSLT)
- syslog() Function (Python, SLAX, and XSLT)
- trace() Function (Python, SLAX, and XSLT)
- play_arrow Named Templates for Automation Scripting
- play_arrow Named Templates in the jcs Namespace
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- play_arrow Manage Automation Scripts
- play_arrow Store and Enable Scripts
- play_arrow Configure a Remote Source for Scripts
- play_arrow Configure the Session Protocol for Scripts
- play_arrow Control Execution of Scripts
- play_arrow Synchronize Scripts Between Routing Engines
- play_arrow Convert Scripts Between SLAX and XSLT
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- play_arrow Commit Scripts
- play_arrow Commit Scripts Overview
- play_arrow Create and Execute Commit Scripts
- Required Boilerplate for Commit Scripts
- XML Syntax for Common Commit Script Tasks
- Design Considerations for Commit Scripts
- How to Avoid Potential Conflicts When Using Multiple Commit Scripts
- Line-by-Line Explanation of Sample Commit Scripts
- Control the Execution of Commit Scripts During Commit Operations
- Control the Execution of Commit Scripts in the QFabric System
- Configure Checksum Hashes for a Commit Script
- How to Process Large Configurations Against Commit Scripts
- Example: Retrieve the Pre-Inheritance Candidate Configuration in a Commit Script
- play_arrow Generate a Custom Warning, Error, or System Log Message Using Commit Scripts
- Overview of Generating Custom Warning, Error, and System Log Messages
- Generate a Custom Warning, Error, or System Log Message in Commit Scripts
- SLAX and XSLT Commit Script Tag Elements to Use When Generating Messages
- Example: Generate a Custom Warning Message
- Example: Generate a Custom Error Message
- Example: Generate a Custom System Log Message
- play_arrow Generate Persistent or Transient Configuration Changes Using Commit Scripts
- Overview of Generating Persistent or Transient Configuration Changes Using Commit Scripts
- Generate a Persistent or Transient Configuration Change in SLAX and XSLT Commit Scripts
- Generate a Persistent or Transient Configuration Change in Python Commit Scripts
- SLAX and XSLT Commit Script Tag Elements to Use When Generating Persistent and Transient Configuration Changes
- Remove a Persistent or Transient Configuration Change Using Commit Scripts
- Example: Generate Persistent and Transient Configuration Changes Using Commit Scripts
- play_arrow Create Custom Configuration Syntax with Commit Script Macros
- Overview of Creating Custom Configuration Syntax with Commit Script Macros
- Create Custom Configuration Syntax with Commit Script Macros
- Create a Commit Script Macro to Read the Custom Syntax and Generate Related Configuration Statements
- Example: Creating Custom Configuration Syntax with Commit Script Macros
- play_arrow Commit Script Examples
- Example: Adding a Final then accept Term to a Firewall
- Example: Adding T1 Interfaces to a RIP Group
- Example: Assign a Classifier Using a Commit Script
- Example: Automatically Configure Logical Interfaces and IP Addresses
- Example: Configure Administrative Groups for LSPs
- Example: Configure a Default Encapsulation Type
- Example: Configure Dual Routing Engines
- Example: Configure an Interior Gateway Protocol on an Interface
- Example: Control IS-IS and MPLS Interfaces
- Example: Control LDP Configuration
- Example: Create a Complex Configuration Based on a Simple Interface Configuration
- Example: Impose a Minimum MTU Setting
- Example: Limit the Number of ATM Virtual Circuits
- Example: Limit the Number of E1 Interfaces
- Example: Load a Base Configuration
- Example: Prepend a Global Policy
- Example: Prevent Import of the Full Routing Table
- Example: Require Internal Clocking on T1 Interfaces
- Example: Require and Restrict Configuration Statements
- play_arrow Junos XML and XSLT Tag Elements Used in Commit Scripts
- play_arrow Troubleshoot Commit Scripts
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- play_arrow Op Scripts
- play_arrow Op Scripts Overview
- play_arrow Create and Execute Op Scripts
- Required Boilerplate for Op Scripts
- Map Operational Mode Commands and Output Fields to Junos XML Notation
- How to Use RPCs and Operational Mode Commands in Op Scripts
- Declare and Use Command-Line Arguments in Op Scripts
- Configure Help Text for Op Scripts
- Define Operational Mode Commands to Allow in an Op Script
- Enable an Op Script and Define a Script Alias
- Configure Checksum Hashes for an Op Script
- Execute an Op Script on the Local Device
- Execute an Op Script from a Remote Site
- Disable an Op Script
- play_arrow Op Script Examples
- Change the Configuration Using SLAX and XSLT Scripts
- Example: Change the Configuration Using SLAX and XSLT Op Scripts
- Example: Change the Configuration Using Python Op Scripts
- Example: Customize Output of the show interfaces terse Command Using an Op Script
- Example: Display DNS Hostname Information Using an Op Script
- Example: Find LSPs to Multiple Destinations Using an Op Script
- Example: Restart an FPC Using an Op Script
- Example: Export Files Using an Op Script
- Example: Import Files Using an Op Script
- Example: Search Files Using an Op Script
- play_arrow Provision Services Using Service Template Automation
- play_arrow Troubleshoot Op Scripts
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- play_arrow Event Policies and Event Scripts
- play_arrow Event Policy Overview
- play_arrow Event Policy Triggers
- Use Correlated Events to Trigger an Event Policy
- Trigger an Event Policy Based on Event Count
- Example: Trigger an Event Policy Based on Event Count
- Use Regular Expressions to Refine the Set of Events That Trigger a Policy
- Example: Controlling Event Policy Using a Regular Expression
- Generate Internal Events to Trigger Event Policies
- Use Nonstandard System Log Messages to Trigger Event Policies
- Junos Logger Utility
- play_arrow Event Policy Actions
- Configure an Event Policy to Execute Operational Mode Commands
- Configure an Event Policy to Change the Configuration
- Example: Changing the Configuration Using an Event Policy
- Example: Changing the Interface Configuration in Response to an Event
- Execute Event Scripts in an Event Policy
- Change the Configuration Using an Event Script
- Configuring an Event Policy to Pass Arguments to an Event Script
- Configure Event Policies to Ignore an Event
- Example: Ignore Events Based on Receipt of Other Events
- Overview of Using Event Policies to Raise SNMP Traps
- Example: Raise an SNMP Trap in Response to an Event
- Understanding the Event System Log Priority in an Event Policy
- Example: Configuring the Event System Log Priority in an Event Policy
- Example: Limit Event Script Output Based on a Specific Event Type
- play_arrow Configure Event Policy File Archiving
- play_arrow Configure Event Policy Privileges
- play_arrow Event Scripts Overview
- play_arrow Create and Execute Event Scripts
- play_arrow Troubleshoot Event Policies and Event Scripts
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- play_arrow SNMP Scripts
- play_arrow SNMP Scripts Overview
- play_arrow Create and Execute SNMP Scripts
- play_arrow SNMP Script Example
- play_arrow Troubleshoot SNMP Scripts
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- play_arrow Configuration Statements and Operational Commands
ON THIS PAGE
XSLT Overview
Commit scripts, op scripts, event scripts, and SNMP scripts can be written in Extensible Stylesheet Language Transformations (XSLT), which is a standard for processing Extensible Markup Language (XML) data. XSLT is developed by the World Wide Web Consortium (W3C) and is accessible at http://www.w3c.org/TR/xslt .
XSLT Advantages
XSLT is a natural match for Junos OS, with its native XML capabilities. XSLT performs XML-to-XML transformations, turning one XML hierarchy into another. It offers a great degree of freedom and power in the way in which it transforms the input XML, allowing everything from making minor changes to the existing hierarchy (such as additions or deletions) to building a completely new document hierarchy.
Because XSLT was created to allow generic XML-to-XML transformations, it is a natural choice for both inspecting configuration syntax (which Junos OS can easily express in XML) and for generating errors and warnings (which Junos OS communicates internally as XML). XSLT includes powerful mechanisms for finding configuration statements that match specific criteria. XSLT can then generate the appropriate XML result tree from these configuration statements to instruct the Junos OS user-interface (UI) components to perform the desired behavior.
Although XSLT provides a powerful scripting ability, its focus is specific and limited. It does not make Junos OS vulnerable to arbitrary or malicious programmers. XSLT restricts programmers from performing haphazard operations, such as opening random Transmission Control Protocol (TCP) ports, forking numerous processes, or sending e-mail. The only action available in XSLT is to generate XML, and the XML is interpreted by the UI according to fixed semantics. An XSLT script can output only XML data, which is directly processed by the UI infrastructure to allow only the specific abilities listed above—generating error, warning, and system log messages, and persistent and transient configuration changes. This means that the impact of commit scripts, op scripts, event scripts, and SNMP scripts on the device is well-defined and can be viewed inside the command-line interface (CLI), using commands added for that purpose.
XSLT Engine
XSLT is a language for transforming one XML document into another XML document. The basic model is that an XSLT engine (or processor) reads a script (or style sheet) and an XML document. The XSLT engine uses the instructions in the script to process the XML document by traversing the document’s hierarchy. The script indicates what portion of the tree should be traversed, how it should be inspected, and what XML should be generated at each point. For commit scripts, op scripts, event scripts, and SNMP scripts, the XSLT engine is a function of the Junos OS management process (mgd).
Figure 1 shows the relationship between an XSLT commit script and the XSLT engine.
XSLT Concepts
XSLT has seven basic concepts. These are summarized in Table 1.
XSLT Concepts | Description |
|---|---|
XPath | Expression syntax for specifying a node in the input document |
Templates | Mechanism for mapping input hierarchies to instructions that handle them |
Parameters | Mechanism for passing arguments to templates |
Variables | Mechanism for defining read-only references to nodes |
Programming instructions | Mechanism for defining logic in XSLT |
Recursion | Mechanism by which templates call themselves to facilitate looping |
Context (Dot) | Node currently being inspected in the input document |
