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Set Vars

Overview​

The Set Vars action is used to define or update global variables in a Traffic Policy's runtime context. Subsequent actions or expressions can reference these variables for conditional logic through expressions or dynamic interpolation.

Configuration Reference​

This is the Traffic Policy configuration reference for this action.

Supported Phases​

on_http_request, on_http_response, on_tcp_connect

Type​

set-vars

Configuration Fields​

  • varsarray of map[string]any of size 1Required

    vars is a list of maps that have a key of string and a value of any valid CEL type

    Each map must be of exactly size 1, and represents one variable where the key is the name of the variable

Behavior​

The set-vars action allows you to define your own global variables to be used in future actions or expressions. After being defined, they can be accessed using the "${vars.<name>}" syntax within CEL interpolated strings. The variables can be of any valid CEL type, including strings, booleans, doubles, null, maps, and lists.

CEL Interpolation​

Strings can also support CEL interpolation, allowing for dynamic values and types. Within string values, you can use the syntax ${<expression>} to evaluate expressions and include their results in the string. CEL-interpolated strings that are exactly of the form "${vars.<name>}" will resolve to the evaluated type. Strings that contain CEL-interpolated substrings within them such as sample ${conn.tls.client.pem} here will convert all CEL-interpolated substrings to strings

Scoping​

The variables defined in the set-vars action are scoped to the Traffic Policy and are not accessible outside of it. Variables defined in each of the three phases (on_http_request, on_http_response, on_tcp_connect) are scoped to that phase, and cannot be accessed in other phases.

Referencing other variables and macros​

CEL-interpolated strings may reference all other variables and macros available to traffic policies. This also includes variables previously defined in the same or previous set-vars actions. This allows for powerful dynamic behavior and customization of your Traffic Policy.

Examples​

Basic Example​

The following Traffic Policy configuration is an example configuration of the set-vars action.

Example Traffic Policy Document​

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CEL Interpolation Example​

The following Traffic Policy configuration is an example of using CEL-interpolation with the set-vars action.

Example Traffic Policy Document​

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Setting Vars based on Previous Vars Example​

The following Traffic Policy configuration is an example of setting vars based on previous vars with the set-vars action. Variables are determined in the order in which they are listed in the configuration list.

Example Traffic Policy Document​

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