Brocade Virtual ADX OpenScript Programmer’s Guide (Support Manual do Utilizador descarregar pdf (Página 12)

4 Brocade Virtual ADX OpenScript Programmer’s Guide

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Using Perl on the Brocade Virtual ADX

Architecture of the OpenScript engine

Because script parsing is highly CPU-intensive it is performed entirely on the management

processor (MP) of the Brocade Virtual ADX. If the compilation succeeds on the MP, the script is

downloaded to the application processor (BP) for installation. The BP prepares the script by

generating machine byte code and binds it by inlining it in the packet processing path for the virtual

server and service. This process is displayed in Figure 2.

FIGURE 2 OpenScript compilation and installation process

Using Perl on the Brocade Virtual ADX

The Perl implementation on the Brocade Virtual ADX is based on Perl Version 5.12. It preserves the

core syntax and semantics of the core language as specified at the perldoc site:

http://perldoc.perl.org/5.12.4/perlsyn.html.

Perl variables

Perl variable scoping on the Brocade Virtual ADX

• Any lexical variable declared as “my” within a script is re-initialized on every run. Variable

scoping is limited to the script it resides in. This means that variables are not visible to

other scripts.

• A state lexical variable behaves like a C language static, with persistent value across

reruns. It is never re-initialized like “my”.

USB

OpenScript Engine

IPC

Compile

Scrip t

Machine

Bytecode

Data Trac

Control Plane

Data Plane

CLI

Preprocess &

Compile

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Brocade Virtual ADX OpenScript Programmer’s Guide (Support Manual do Utilizador Página 12