FIT Expression and Function

Overview

Variable

Global Function

Expression

String Interpolation

Overview

In FIT YAML, there are several sections where variables can be defined and further used in expression and string interpolation.

GDR variables are also supported.

Variable

Naming Convention

Variables can be defined in line pattern and eigen variables.

•Variable names are case-sensitive.

•Variable names must begin with a letter of the alphabet or an underscore( _ ).

•Variable names can contain letters and numbers.

•No spaces or special characters are allowed.

•The variable names should not have any duplicates.

•Variable names should not be identical to the names of built-in functions or built-in keywords.

If the variable name being defined is not valid, the current decode process will be terminated.

Variable Level

Variable Definition Type

Variable Level

Definition

Line Pattern Variable

SubFI/Device Level

Defined in feature.configlet.match_rules.patterns .

Eigen Variable

SubFI/Device Level

Defined in feature.configlet.eigen_variables .

Device GDR Variable

Device Level

All device GDR variables.

Interface GDR Variable

Interface Level

All interface GDR variables. Physical interfaces only.

FIG Variable

FIG Level

A unique hash value for FIG groupby eigen variable

Variable Data Type

There are seven data types can be defined in line pattern or eigen variables. Besides that, device/interface GDR variables can also be utilized.

•Device

•String

•Number

•Bool

•IP

•IPv6

•Mac

•Time

Global Function

Function

Definition

Example

OrderIndex(string: deviceVarName, bool:asc=true): int

Get the order of current device in the feature intent group.

Can only be used in network_intents.ni_inputs.devices.[R1].device_condition.

OrderIndex("$priority")==0

OrderIndex("$device.priority")==0

Combine(paras any[] values): string

Combine multiple values into a sorted string.

Can only be used in feature.configlet.

Combine($ip1, $ip2, $bgp, $remoteBGP)

IP(string: ipString, string: maskString): ip

Create IPv4 object.

IP($ip,$mask)

IP($ipWithMask,"")

IPv6(string: ipString, string: maskString): ipv6

Create IPv6 object.

IPv6($ip,$mask)

IPv6$ipWithMask,"")

Ternary(bool: condition, any: value1WhenTrue, any: value2WhenFalse): any

Ternary.

SameSubnet(ip ip1, ip ip2): bool

Check whether the given ipv4 subnets are the same.

The mask length should be the same.

SameSubnet(ipv6 ip1, ipv6 ip2): bool

Check whether the given ipv6 subnets are the same.

The mask length should be the same.

Num(string: str1): number

Create a number object.

Num("90")

Str(any: obj)

Create a string object.

Str("SampleString")

Expression

The expression here is a statement written using a subset of C# language specifications.

There are several sections in FIT YAML that support the usage of string interpolation.

FIT YAML Tag

Type

Variables Level

Multiple Variable Values

feature.configlet.match_rules.relation

Feature Decode

Device level variables

Will generate commands for all possible values combinations.

feature.configlet.eigen_variables.expression

Feature Decode

Device level variables

Will generate commands for all possible values combinations.

feature.cross_relation.qualification

Feature Decode

Device level variables

Will generate commands for all possible values combinations.

network_intents.ni_inputs.devices.[R1].device_condition

NI

Device level variables

Will generate commands for all possible values combinations.

network_intents.ni_inputs.devices.[R1].parameters.[xx]

NI

Device level variables

Only the first value will be used if multiple values are available.

flash_probes.qualification

Flash Probe

Device / Interface level variables

Will generate commands for all possible values combinations.

flash_probes.generate_condition.variables.parameters.[xx]

Flash Probe

Device / Interface level variables

Only the first value will be used if multiple values are available.

String Interpolation

Introduction

•https://docs.microsoft.com/en-us/dotnet/csharp/language-reference/tokens/interpolated

•The expression is supported in "{ }".

•To include a brace, "{" or "}", in the text produced by an interpolated string, use two braces, "{{" or "}}".

If string interpolation is not valid, current decode process will be terminated.

Examples

There are several sections in FIT YAML that support the usage of string interpolation.

FIT YAML Tag

Type

Variables Level

Multiple Variable Values

Examples

feature.configlet.commands

Feature Decode

Device level variables

Will generate commands for all possible values combinations.

show standby interface {$intfName1} {$standbyName1}

network_intents.path

NI

FIG level variables

Only the first value will be used if multiple values are available.

xxxx/xxxx/General_BGP_{ $crossRelationHash }

flash_probes.name

Flash Probe

Device / Interface level variables

Only the first value will be used if multiple values are available.

BGP_Flapping_{ $intfName }