Example: Creating Custom Configuration Syntax with Commit Script Macros

This example uses the following hardware and software components:

• Device running Junos OS.

• Junos OS Release 16.1R3 or later release when using a Python script.

Table 1 shows a macro containing custom syntax and the corresponding expansion to standard Junos OS command-line interface (CLI) syntax.

protocols {
    mpls {
        apply-macro blue-type-lsp {
            10.1.1.1;
            10.2.2.2;
            10.3.3.3;
            10.4.4.4;
            color blue;
            group-value 0;
        }
    }
}

protocols {
    mpls {
        admin-groups {
            blue 0;
        }
        label-switched-path blue-lsp-10.1.1.1 {
            to 10.1.1.1;
            admin-group include-any blue;
        }
        label-switched-path blue-lsp-10.2.2.2 {
            to 10.2.2.2;
            admin-group include-any blue;
        }
        label-switched-path blue-lsp-10.3.3.3 {
            to 10.3.3.3;
            admin-group include-any blue;
        }
        label-switched-path blue-lsp-10.4.4.4 {
            to 10.4.4.4;
            admin-group include-any blue;
        }
    }
}

In this example, the Junos OS management (mgd) process inspects the configuration, looking for apply-macro statements. For each apply-macro statement with the color parameter included at the [edit protocols mpls] hierarchy level, the script generates a transient change, using the data provided within the apply-macro statement to expand the macro into a standard Junos OS administrative group for LSPs.

For this example to work, an apply-macro statement must be included at the [edit protocols mpls] hierarchy level with a set of addresses, a color, and a group-value parameter. The commit script converts each address to an LSP configuration, and the script converts the color parameter into an administrative group.

Following are the commit script instructions that expand the macro in Table 1 and a line-by-line explanation of the script:

XSLT Syntax

Lines 1 through 8 (and Lines 43 and 44) are the boilerplate that you include in every XSLT commit script. For brevity, Lines 1 through 8 are omitted here.

Line 9 assigns the [edit protocols mpls] hierarchy level to a variable called mpls.

Line 10 selects every apply-macro statement at the [edit protocols mpls] hierarchy level that contains the color parameter. The sample configuration in Table 1 contains only one apply-macro statement. Therefore, this <xsl:for-each> programming instruction takes effect only once.

Line 11 assigns the value of the color parameter, in this case blue, to a variable called color.

Line 12 assigns the value of the group-value parameter, in this case 0, to a variable called group-value.

Lines 13 through 15 generate a transient change at the [edit protocols mpls] hierarchy level.

Lines 16 through 23 add the admin-groups statement to the configuration and assign the value of the color variable to the group name and the value of the group-value variable to the group value.

The resulting configuration statements are as follows:

Line 24 selects the name of every parameter that does not have a value assigned to it, which in this case are the four IP addresses. This <xsl:for-each> programming instruction uses recursion through the macro and selects each IP address in turn. The color and group-value parameters each have a value assigned (blue and 0, respectively), so this line does not apply to them.

Line 25 adds the label-switched-path statement in the configuration.

Lines 26 through 28 assign the label-switched-path a name that concatenates the value of the color variable, the text -lsp-, and the current IP address currently selected by Line 24 (represented by the “ .” ).

Line 29 adds the to statement to the configuration and sets its value to the IP address currently selected by Line 24.

Lines 30 through 34 add the admin-group include-any statement to the configuration and set its value to the value of the color variable.

The resulting configuration statements (for one pass) are as follows:

Lines 35 through 42 are closing tags.

SLAX Syntax

The equivalent SLAX script is:

Python Syntax

The following Python syntax produces the identical configuration changes:

For more information about this example, see Example: Configure Administrative Groups for LSPs.